Can't Heat 4th Floor Apartments in Front

Jeremy_16

Hi everyone,



We manage a 4 story brick building with 4 apartments per floor (2 in the back

and 2 in the front per floor). We have one pipe steam heat with oil fuel. The

boiler (see pics) is located near the back of the building so the mains that go

to the 2 stacks of apartments in the back are shorter than the mains that run

to the 2 stacks of apartments in the front of the building. The mains to the

back apartments are about 20-25 feet long after they exit the boiler room (the main

vents on the short mains probably are not working, but the back of the building

has no problems heating so we haven't touched them). The mains that go to the

front 2 apartments are about 55-60 feet long after they exit the boiler room.



We used to have an old heat timer that was probably out of calibration and the

building used to overheat (heat ran day and night). We have since installed the

MPC Platinum Panel by Heat Timer with an internet communication panel and space

sensors in each unit. The building runs cycles like the normal heat timer, but

it takes feedback from the space sensors and will not run a cycle if the

average temperature is above the set average. Our set average is 70 degrees

during the day and 67 degrees at night. The system works very well in mild

weather and usually works ok once the weather is consistently cold. However, if there is a sharp drop in outdoor temperature, we sometimes run into problems.



At 11:00 PM the night cycle starts and the boiler turns off and will not run

cycles until the average temperature in the building drops to 67 degrees. This

works very well on most days. It keeps the building cool at night for sleeping

weather. In the morning the heat timer runs a boost cycle (the cycle gets

longer the colder it is outside. It sometimes runs for 1.5 hours if very cold)

When the temperature drops from a day with a high of about 45 to 50 degrees to

the next day where the temperature is 20 to 30 degrees the two apartments in

the front of the building on the top floor do not heat up. They keep falling in

temperature and it is very difficult to get them to heat up (even with the heat in bypass for 2 hours). Additionally, the

front top floor apartments are always cooler than the rest of the building, but

usually within 3 to 4 degrees of the average.



What happens is that starting at 11:00 PM the boiler turns off for heat, the

pipes get cold, temperatures in the building fall. The front units are cooler

to begin with because the sun is on the back side of the building during the

day. Since the boiler stays off for a longer time at night now, the pipes get

cold. In the morning the boiler starts up, and temperatures climb in most of

the units with the boost period, but temperatures barely rise in the top floor

front units. (They then start to fall throughout the day) The other units in

the front usually heat up with the back ones, but are still a bit cooler than the back ones.



We tried to solve this problem by doing a few things:





1. We made sure that all supply valves were open and replaced some radiator

vents in the units. (All radiators are able to heat up and hold steam)



2.We installed new main vents at the end of each run to the front of the

building (see pics of old vents and new vents).



3. We even installed master vents on the top floor to help get the air out and

the steam up the apartments faster. (see pics).



What else can we do to get these apartments to heat up along with the rest of

the building? Any help is appreciated.





Hopefully that wasn't too long, I just wanted to provide as much pertinent

information as possible. If you need any more information, please let me know.





Thanks,



Jeremy





 

Jamie Hall

Can you confirm

a couple of assumptions I might make?  That is -- the third floor front apartments heat OK, just like the rest of the building?  And the front apartments are all on the same riser, or same two risers?  If they there are two risers (one for each stack) for the front apartments, do both top floor front apartments behave the same way?



You see... what I'm looking for is what, if anything, is common between the two top floor front apartments, which is not shared by the rest of the apartments.



For some reason -- and we'll figure it out, I'm sure -- the two top floor front apartments aren't getting steam from a cold start.  Logically something is in common for those two, shared by nothing else -- and that something is preventing steam from getting there under certain conditions.  It is most likely that somewhere in the piping there is a sag or loop which is allowing water to collect, and keeping steam from getting by... but there are other possibilities.

jpf321

insulation and resistance

Jeremy --



I'd like you to have a look at my Excel venting sheet (link in signature) .. it's not enough to simply vent all the rads .. you are going to need to provide some resistance to the back apts to equally send all the steam to all places in "roughly the same time" ... in my system, I have a pair of mains (insulated) and it takes roughly 4minutes extra to go an extra 10ft of main length (2in pipe). since your mains are so drastically different, that could be 20minutes just to get to end of the front mains. all the while, the back rads are busy on their way to satisfying avg building temp.



using the excel sheet .. i would play with the minutes to vent column (which really translates to resistance) and i would raise the minutes to vent higher for the back mains and lowest runs ... the lowest minutes to vent values should be your highest front locations. please note that if you set all minutes to vent to be the same value, this should equate to all rads getting heat at the same time. additionally, since you have added additional venting, i think you should use each "vented segment" as a different piece of equipment in the first column.



and just a note, although it does look pretty good from your pictures .. try to insulate everything you have access to using 1" fiberglass pipe insulation.



let us know.

Jeremy_16

Response to Jamie

Jamie,



The third floor front apartments heat ok. They aren't as hot as the back, but

only a degree or two below the average (not 10 degrees or more below the

average like the top floor front apartments when the weather changes). (See

temperature data and boiler cycle time data in pictures below)



Apt 7, 8 are back 3rd floor.



Apt. 9,10 are front 3rd floor.



Apt. 11,12 are back 4th floor (top floor)



Apt. 12A, 14 are front 4th floor (the top floor hard to heat apts)





If you look at the data from 12-15 to 12-16, the top front apts (12A and 14)

fall in temperature over night between 12-15 and 12-16, they come up a bit in temperature in

the morning with the boost, but starting at 8AM or 9AM on the 16th they start

to drop again. This always happens when the temperature drops quickly. You'll

see that on the 16th, the boiler ran throughout the day, but the temperatures

in apts 12A and 14 keep dropping. Once they drop more than 7 degrees below the

average space temperature they are thrown out of the equation by the heat timer

(this works well if someone leaves a window open or likes to cook often, but

not when you can't heat the cold apts)



There are a few risers and radiators in the front units. I attached a diagram

to show where they are. The first riser along the very long main to the front

of the building is located between the kitchen and one of the bedrooms. The

farthest riser is in between the bedroom and livingroom. The farthest riser is

where we put the master vent.



The front units are mirror images that share the same livingroom and hallway

wall. Neither of the top front units share the same riser or even the same

main. What they have in common is that they are the farthest apartments piping

wise from the boiler. All apartments below them have exposed risers coming up

through the apartments that are not insulated, but the top floor does not have

risers in the rooms because the radiators connect directly in at the top of the

riser. Would that make a big difference? Also, parts of the mains may be

missing insulation once they are in the walls after the boiler room. I would

need to check to verify though.



The radiators in apt. #12A and #14 are all able to get hot. I put the boiler in

bypass mode for about 2.5 hours today and the radiators got hot all the way

across. However, I kept the building on so long that the back apartments were

near 80 degrees and the hard to heat apartments were still only mid to high

60's.



Any other information you need please ask. Thanks for the help thus far.



-Jeremy

Jeremy_16

response to jpf321

jpf321,



Thanks for your response. Are you

suggesting that I try to slow the venting in the back of the building so the

front has more time for the steam to get to the risers? If so, how would you

suggest I do this? (buy radiator vents with a slower venting rate or something

else?) We are renovating an apartment in the back of the building so I have

access to some of the mains that go to the back of the building. One back main

has an area where there used to be a main vent, but is now plugged (that should

slow down the steam) and the other main has a vent that looks like the old main

vent that used to be in the front of my building (see pictures from original

post). That vent seems to be painted over so it probably doesn't work anyway.



I guess I’ve been trying to speed up

the front, rather than slow down the back. That way the boiler will run for

less time. I will take a close look at that excel sheet tomorrow with fresh

eyes. I will probably have some more questions for you though.



All parts of the main that I have

access to are insulated (I’ll double check to make sure). There may be some

areas along the main that are not insulated. If I can access them, I will

surely add insulation. Should I open up areas to insulate if I find that some

portions of the pipe are not insulated? Would this make a dramatic difference?

If yes, then I would consider opening some walls.





Thanks,

Jeremy

Jamie Hall

Do the

different floors have different risers, or do all the apartments in a stack (say, 12A and the apartments under it) all share the same risers?



I'm beginning to think that, curiously, a combination of insulation, or the lack of it, and venting may be what we are looking at -- but I want to sleep on it.

jpf321

running out ...but ..

a quick response before i head out for the evening.



have a go at the excel sheet .. and set all your times to a constant to start .. perhaps 5mins. that is, your desire to vent the entire system (including having hot rads) within 5mins .. this is not going to be the real-life effect so don't get too excited .. but the theoretical model .. then have a look at the various "CFM to vent" needs for the various system elements.



please remember that steam is going to travel the path of least resistance .... it you want it to head towards the front first (or in a balanced manner) then you should probably work to slow the rear .. and yes it may mean putting smaller vents in the rear... the excel sheet has recommendations for both Gorton rad vents and Hoffman 1A adjustable vents. my email address is in the sheet, you can contact me directly if you like.



i would not open any walls to insulate until such time as we have worked on a better balance. to begin with, it might be useful to time the system as it stands currently .. i did see pipes in your pictures that were not insulated .. (black pipes shown in rooms with rads) .. those look like they are accessible



time until boiler header get steam_____

time until each main end gets steam_______

time until each rad get steam______



this will provide you a baseline and allow you/us to understand improvements as they are made.

nicholas bonham-carter

putting the 16 unit system in good order

if it were my newly acquired building, i would :

1. install a vaporstat, and 0-16 oz. gauge, setting the pressure at 8 oz. max. 

2.wrap insulation strips around any exposed mains any where between boiler and radiator.

3. buy and install at least 2 gorton#2's [on antlers]  for each dry return, or end of counter-flow main. check that steam is getting to all main pipe ends in the basement at the same time.

4. clean the sight-glass, and verify that the water is clean, and pure.

5.temporarily turn off the night setback during the investigatory period, as well as any auto/over-fill setup. i would have a wire with 2 alligator clips so i could short the control system, making the boiler run constantly for the tests.

6. after getting the steam at correct low pressure to the furthest risers in the basement simultaneously, i would move to the top floor, and see that steam is arriving at the top floor radiator shut-off valves simultaneously. check the intermediate floors after the top. the goal is to enable steam to arrive at all radiators on all floors virtually simultaneously. any big radiator vents could be saved for any slow top radiators. in the lost art of steam heating, there is mention made of steam travelling through pipes at a speed of 60 mph, so it should not take to long for it to get to the stop valves of any radiator. disregard any measurement of room temperature until you have the steam moving quickly.

7.once the steam is in the right places as quickly as possible, then it is time to start making whatever control system you have turn the boiler off and on at the right time. it may not even have the right control, for the purpose, but you won't know that until you have the steam working properly.

in the next few weeks i would watch the waterline for loss of water, or getting too dirty, and act accordingly.--nbc

Steamhead

Jeremy, these guys are right

when they say to speed up the front main rather than slow the rear one.



Measure the length and diameter of both mains and tell us what vents you now have on them. This will give us a starting point. You may need something like what you see in the picture below.

Jeremy_16

The stacks,

like apt. 12A and apartments underneath, share the same risers.

jpf321

take steamhead's info over mine

I'm an enthusiastic newbie .. i try to do the right things .. but if steamhead says to speed up front rather than slow rear .. let's work on getting that done. Have a look at this article, written by another "authority" and give it some thought as well: [url=http://www.heatinghelp.com/article/11/Hot-Tech-Tips/1551/Taking-Another-Look-at-Steam-Boiler-Sizing-Methods-by-Dave-Boilerpro-Bunnell]http://www.heatinghelp.com/article/11/Hot-Tech-Tips/1551/Taking-Another-Look-at-Steam-Boiler-Sizing-Methods-by-Dave-Boilerpro-Bunnell



after thinking some about steamhead's comment .. it's not so far off of mine .. the general answer is to balance the system to ensure that steam arrives everywhere pretty much simultaneously .. I think that in the end, it will mean a "slower" back (relative to front)...however, since you have the back setup already .. lets speed the front (relative to back) from the current back setup .. rather than change the back to come down to the current front setup...same premise .. different starting point...as Einstein stated it's all about relativity. I guess I just learned a valuable lesson once again .. always look towards speeding up rather than slowing down relatively speaking...again, generally, you want to make all paths equally attractive as paths of least/equal resistance...and let's start with the current back and speed from there.



get back to us with the main lengths and diameters as steamhead suggests.



i did have other question out of my curiosity .. in the floorplan you provided, where it the t-stat located? do all apts have the same floorplan? are the t-stats located in the same place in each apt?

Jeremy_16

A few Questions and Responses

Nicholas Bonham-Carter,



Thanks for the suggestions. I have a few questions for you or anyone that can

answer:



1. We have a vaporstat already. Not sure if it is set correctly. Please take a

look at the picture and advise on where to set MAIN and DIFF. on the gauge if

it should be different from where it is now.



2. I'll take a look at what mains I can see tomorrow and plan on adding

insulation to any accessible section that isn't covered. Should insulation go

around the header as well?



3. Right now we only have one main vent at the end of each long main to the

front. We have since sealed them in the wall, but left a little panel for

access. If needed, we could get in there and install more vents. I attached a

picture of one of the main vents we installed. I believe it is a Hoffman #76. I

know you recommended the Gorton #2, but is the one we have ok as well?



The master vent at the top of the stack is a Hoffman#75.

Jeremy_16

Steamhead:

I've been reading Dan Holohan's books. That's when I realized about trying to speed the front up rather than throttle back the rear units. However, what I have done so far doesn't seem to have been enough.



I will measure the length and diameter of the mains tomorrow. Should I take the measurements of diameter from the area closest to the main vents? I'm not sure if the main diameter gets smaller as it gets further from the boiler room. The diameter of the mains in the boiler room look larger than near the main vents at the end of the run.



I included a close up picture above of one of the main vents that we installed in the front of the building. I'll put it in here as well. Its currently inside the wall, so I did my best to read it off of the picture I took. It says No. 76 Main Vent Vacuum Valve. ITT McDonnell & Miller. Under their website it's listed under Hoffman Specialty Model 76 under vents then steam: [url=http://www.hoffmanspecialty.com/HS-General-Catalog.asp]http://www.hoffmanspecialty.com/HS-General-Catalog.asp



The master vent at the top of the stack is Hoffman #75 Main Vent Air Valve.



Are the vents currently installed the right kind? Do I need more venting?



Thanks for all of the help.

Jeremy_16

jpf321:

Thanks for the article. It has some good information. I

think I'll probably need more main venting. In another post I listed the type

of main vents we have in the building and asked if anyone thought I should

change them, add to them, etc.



I'll get you the guys the main lengths and diameters ASAP.



 To answer your questions: All front apartments have the same floor plans.

They are all two bedroom apartments (2 per floor  and mirror images of each other). The back of the building contains

one bedroom apartments. When you say, "are the t-stats located in the same

place in each apt" is t-stat, thermostat?





-Jeremy

jpf321

measure are precisely as possible

yes t-stat = thermostat and I guess what I meant to say was temp sensor since I realize they are connected remotely.



measure as precisely and with as much detail as possible .. the goal is to get a proper figure for the air which is within the system. measure from the header of the boiler to the end .. you already mentioned mains towards back at about 25ft and towards front @ 50ft ... but try as best you can to determine the diameters and lengths ..

for example ..

front main .. header + 35ft @ 2in + 15ft @ 1-1/2in + 10ft @ 1-1/4in

front main current vents: 1piece hoffman 76 at far end and ????

do the same for rear main.

you are really trying to paint as detailed a picture as possible of the system piping short of actually drawing it out. feel free to post pictures liberally as well.



(this chart may help you to measure AROUND (outside circumference - column 3) the pipe and then determine pipe-size (inner diameter - column 1))

DavidK_2

I'm no expert,

but your vapourstat does not seem to be set properly. It looks like you have 14 oz cutout, but virtually no differential. Do you have problems with the boiler short cycling? You need some differential between cut in and cut out pressures. It appears to be a subtractive vapourstat, so you might try 14 cutout, and 7 differential (which would have your system working between 7 and 14 oz of pressure - this might be higher than you need)



If somebody else suggests different numbers, use them - I'm no pro.

I'm pretty sure no differential is wrong so since nobody commented on it I thought I would.



Assuming your mains are well vented, I'd suggest bigger vents on the radiators in the cold rooms. This should allow them to fill with steam faster. The conventional wisdom is that vent size should depend on radiator size - probably a good rule of thumb, assuming that the radiators were properly sized for the heat loss of the room. But if a room is still cold, then more venting can help if the radiators never fill with steam during normal operation..

Jamie Hall

Oh good!

That's one of the older vaporstats -- hang on to it.  They are very very reliable.  You do have it set higher than need be -- try setting the main at 12, and the differential -- which is subtractive -- at 8.  That may turn out to be a tad low, but it's a place to start.



The general buzz also seems right as far as it goes; try getting more venting on the front mains and risers (I'd go for Gorton #2s, both for the main vents and the top of riser vents).  The Hoffman 76 is a very very reliable vent -- but it isn't all that fast, particularly compared to the Gorton #2.  This may help speed things up in front.



I am still concerned, though, that there is a bit more to it, and I think I would be inclined to go to some lengths to make sure that the front mains are well insulated.  I would also be inclined to insulate the risers, if you can get at them.  It is surprising how long it can take steam to make its way through a cold pipe, good venting or no.

Jeremy_16

thanks for the chart and info.

The space sensors in the units are in between the kitchen and the hallway on

the inside hallway wall about chest high. They aren't thermostats though. The

heat-timer controls the heat cycles. If you are unfamiliar with its operation,

here is how it works:



There is an outdoor temperature sensor placed outside on a north facing wall

(to avoid direct sunlight) and an indoor system temperature sensor that is

placed on either the furthest radiator riser or one of the dry returns (it's

usually hard to wire it to the furthest radiator). Regardless, you set the

indoor system sensor at whatever temperature the system sensor reads when the

last radiator in the system or hardest to heat radiator begins to get warm. In

my building that is 160 degrees (although for some reason heat does not seem to

be reaching the last radiator now). The heat timer then runs the burner in a

precycle up to 160 degrees (in my case the boiler runs for about 12 to 16

minutes to get up to a system temperature of 160, it then runs a cycle, see

below).



At that point it is assumed that heat is established (heat has traveled through

all mains and up all risers and has arrived at all radiators) Then the heat

timer runs a 60 minute cycle with an on and off period (example 10 minutes on

50 minutes off). It stays on for longer amounts of time depending on how cold

it is. You need to set day and night temperature cut offs and heat adjustment

(letter A to P: the higher the letter, the longer the cycle). During the day,

the heat timer will not let the burner turn on if it is above the cut off

(default is 55 degrees). If it is 40 degrees outside it calculates a formula

(55 degree cut off minus 40 degrees outside = 15 degrees). If you are set on

letter D heat adjustment, there is a chart that determines that 15 means run

the boiler with a 4 minute cycle. If it is 30 degrees outside it would take 55

degree cut off minus 30 degrees = 25. According to the chart it will run for 9

minutes. It is an exponential scale.



If that paragraph above seemed kind of complicated the whole point is that you

match the heat loss of the building with the increased heat cycle times as it

gets colder (the more heat loss the more heat you need) You change the heat

adjustment until the cycle time seems comfortable. My system is upgraded so I

can go on to the heat timer website to control my system remotely, view

temperature data, cycle times, etc. Check it out: htcontrols.com or check out

the main website at heat-timer.com



The internet control management system is very convenient. It can even send

text messages or e-mails if your burner locks out, if heat does not establish

after 1 hour, if the average temperature drops below a certain set amount, etc.

There is a lot of additional equipment you can attach to it. If you have any

questions, let me know.



But anyway, the space sensors act only as a set back to make sure the building

does not overheat, they do not call for heat.

Jeremy_16

David K and Jamie,

I thought something might be wrong with the vaporstat

settings. Although, we are getting steam in the building without short

cycling... Can someone explain how you come up with the vaporstat settings? I

get that you need high pressure to low pressure in order for the vents to open

and close, but how do you know where to set it and what to change it to if it's

not right.



Jamie, what if we kept the Hoffman 76 and added additional Gorton #2 as well on

the main? That should work, right? Although I guess we would have to do some

additional piping. Is it bad to mix main vents?



UPDATE: It's still well below freezing today and the third floor FRONT of the

building, while still getting heat, is about 5 degrees below average. Basically

the front of the building is a bit colder than the back, but the top floor

front is A LOT worse. It doesn't help with balancing that the sun shines on the

back of the building all day either and not on the front.

nicholas bonham-carter

venting choices

the hoffman vents are quite a bit more expensive, and less capacious than the gorton #2's, which offer "more bang for the buck". as you can never have too much venting, use those generously. with the high velocity of steam at low pressures, there should be no difference in arrival times for front and back, if the air can get out equally quickly.

i agree with the suggested vaporstat settings, as you need  some residual steam in the lines as the boiler re-fires, in order to avoid the sucking in of air. naturally, when the heat-timer is satisfied, the vents will open to enable the subsequent vacuum to be relieved, and prevent possible rise of the boiler water up into the wet returns.

just make sure that the hoffman vents are not the "75/76-H" model which has a vacuum check valve in it. how many mains are there? if they are more than 50 ft. long i would put 2 gortons on each, and can be mixed with the hoffmans. the hoffmans could also be moved to the shorter mains, and the gortons put on the longer ones. the point is use plenty of vents!--nbc

jpf321

pressure discussion

Jeremy --



I asked similar questions about how to determine optimum pressure recently .. have a read through this thread: http://www.heatinghelp.com/forum-thread/128681/Understanding-working-steam-pressure



FYI, I'm still not sure if I understand how to obtain optimimum pressure, however last night I turned my vaporstat down to 3oz with a diff of "bottom scale" .. in my case, due to ignition delay, this differential allows the pressure to drop a few oz. before the fire starts up again. I had been running at 8oz and 4oz .. but I keep dropping it. The way I understand it, as soon as the vents close, no more steam can enter anyway, so why build any pressure at all, I'm trying to trigger cut-out as soon as I begin to sense pressure. And yes, all my rad vents are closed due to steam at 3oz. My longest run is 55ft @ 2in + 20ft @ 1-1/4 into a 27sqft EDR Burhnam Radiant.



BTW, my vaporstat was much more precise at 8oz than at these low pressures .. a setting of 3oz really doesn't trigger until 4.5/5oz. and the bottom scale diff actually causes the needle to be jumped below 0oz.



What I'm particularly please at however is that last night when it was at 16degF with 10mph winds .. my boiler shut-down on pressure but did not start up again (t-stat was satisfied) and it was the shortest cycle I had so far (41mins) with no recycle based on pressure .. but perhaps I just got luck on that cycle. Anyway I ramble.

Jeremy_16

Question about Hoffman 75 or 76-H Vents

One of the main vents I have is Hoffman No 76 Main Vent Vacuum Valve (pictured below). The other is Hoffman 75 Main Vent Air Valve (pictured below). So is the 76 the wrong type to have? I have no idea why there are two different kinds installed. May have been a mistake.



I'm going to post some main measurements in my next post. From measuring so far I think the main to the front could be up to 60 or 70 feet long after the first take off from the boiler header.

Jamie Hall

Pressure settings and vents

First off, let me reiterate -- that vaporstat you have is one of the old mercury ones.  Hang on to it.  Don't let anyone talk you out of it.  It is worth its weight in gold, and then some!  It is much much better than the new ones.  There is only one better pressure controller available, and it's rather expensive -- Gerry Gill makes it.



The optimum setting for pressure is something of a guessing game, once you get in the ballpark.  The idea is to have enough pressure to get the steam reliably to the end of the system -- and 8  to 10 ounces should do that -- and no more.  On some buildings (and yours may be one) it may be necessary to go as high as 14 to 16 ounces on the cut out (for reference, the Empire State Building runs with a 24 ounce cut out!).  The differential controls the length of time between when the burner cuts off and when it cuts back on again.  You don't want it too short, but you don't want it longer than a minute or two, either.  You sort of have to feel your way on it.



On the vents: no reason not to keep the 76.  It's a fine vent, and just about bullet proof.  The best thing to do is to add the Gorton #2 along side it, and just about any combination of Ts and nipples and elbows which will fit your space will do it, so long as the vents sit upright and are above the main (no loops or dips in the piping permitted!).  Sometimes the odd union in between vents, or between the vent piping and the main, can make life a lot easier.  You'll hear such arrangements referred to here on the Wall as "antlers" or "menorahs" --  for obvious reasons.



The problem child apartments would be on the shady side, and on the top floor.  That is the worst possible heat loss in the building!



We'll get there.  No fear.  Just keep the tenants happy... !

Jeremy_16

Main Length and Pipe Diameter

One picture below diagrams how the main runs from the boiler room, underneath one of the front stack of apartments, to each take off riser.



I included as many pictures as I could of the mains so you can follow them in the pictures. The pictures are ordered from near boiler to the end of the main (pics ends at the main vent). I could not get pictures of the middle of the run because the pipes are in the wall. The bad news is that the middle of the run is not insulated. The pipe sits uninsulated in a small space in the wall. Should we open walls to insulate or only as a last resort if more venting does not improve the situation?



It was a bit difficult to get the diameter of the pipes, but my measurements should be pretty close. I start my measurement of one of the mains to the front of the building from the first take off upward from the boiler. Is that the best place to start?



11 ft. @ 4.5 inch outside diameter then 70 ft @ 3.5 inch outside diameter. At the end of the run is a Hoffman #75 Main Vent Air Valve. At the end of the other main run to front (similar in length is a Hoffman #76 Main Vent Vacuum Valve).



I also included pics of the main vents again here. Let me know what this tells you. Any advice is appreciated.



Thanks,

Jeremy

Jamie Hall

See my just previous reply to you, but also

You surely do need more main venting.  The good news is that it looks as though you have enough space to put a nice antler on; use the spread sheet to figure how many Gorton #2s you need on each main, and then start putting things together!  As I said in that previous post, you can keep the 75 and the 76; they won't hurt anything.



The bad news is... get the vents on, and see what happens.  But I'm going to bet that you are going to want to open up that wall... and insulate those mains... don't get out the SawZAll until you try the extra venting, though.

jpf321

looks like...

using the spreadsheet... it looks like 70ft @ 3.5" + 11ft @ 5"(being liberal) requires 2.147cfm @ 3minutes to vent...this equates to 2pcs of Gorton #2.



it would require 5pcs of hoffman #75 or close to 6pcs of hoffman #76 to sufficently vent.



you can see now jeremy how much more venting power the Gorton's have. if you still have questions about how to use the spreadsheet, please contact me directly.

Jeremy_16

Jamie,

Thanks for the info. Is either the menorah or antler setup better than the other? Should either of them be pitched to allow any condensation to escape if it gets up there, or just keep the arrangement level?



It really is tough that the front is shady and the furthest from the boiler. I really need to speed up the mains.

Jeremy_16

Going Forward

I plan on adjusting the vaporstat and increasing the venting to start.



It seems that most people on here prefer the Gorton #2 vs. Hoffman 75 or 76 because the Gorton#2 vents faster. Are there any disadvantages to the Gorton #2 vs the Hoffman 75 or 76. Jamie, you commented that the Hoffman 76 was a very very reliable vent. Is the Gorton #2 the same caliber? What are the pros and cons of each?



I am not as concerned with the cost of the vent as much as reliability and effectiveness. This is a 16 unit tenanted apartment building and I need to make sure everyone has acceptable heat.



The main vents only have a small access panel to allow me to get to them. They are otherwise walled off. I do not want to have to go back in there anytime soon after adding additional venting.



Is the advice to go with Gorton #2 vents for the mains still the same?



If the above does not help, then I guess I'll be opening some walls to insulate the pipes better. Thanks to everyone for the help.



-Jeremy

nicholas bonham-carter

hoffman 76 vacuum vent

that 76 has a disk on the top, which can be removed when the cage is "unscrewed". it will not relieve the vacuum without the removal of the disk. the gortons are much more capacious, and if they are to be mounted in a hard to return to spot, add an extra one, to keep the escape air velocity down as low as possible. this avoids a buildup of debris in the vent. an antler and menorah of 3/4" pipe are equally effective, and i like to put a ball vave under each vent, so as to make later changeouts safer, and easier.

reliability of vents i would think is related to obstruction, from dirt, and i have had good luck with both hoffman, and gorton, as long as they are protected from water-hamer.

you can wait until the system is running perfectly, venting-wise, before insulating the hidden risers. if they are protected in the interior walls, they are not so critical, as if they were out in the open, or in an outside wall.--nbc

jpf321

without knowing the pros/cons...

I think Steamhead's signature picture speaks for itself.



You may also want to look at Rod's post in the thread about my system regarding "Main Vents".. it also includes drawings about how to mount things .. http://www.heatinghelp.com/forum-thread/128365/Looking-for-a-Steam-Pro-for-site-survey-visit#p1179896

jpf321

TRV Video ...

Jeremy -- I just saw this video for the first time .. watch the first 1-2mins .. maybe it will give you something to think about ..

Steamhead

Here are my vent calculations

Since you measured outside diameter, the 4.5" is actually 4" inside diameter and the 3.5" is actually 3".



11' of 4" at 0.9 cubic feet per running foot is 0.99 cubic feet.



70' of 3" at 0.5 cubic feet per running foot is 3.5 cubic feet. Adding the two gives us 4.49 cubic feet of air.



We want to vent that main in about a minute at an ounce of pressure if we can. So:



According to Gerry and Steve,  one Gorton #2 will vent 1.1 cubic feet at one ounce of pressure. Dividing 4.49 by 1.1 = 4.08.



So you should start with four Gorton #2 vents at the very end of the main. You can get away with four of these vents on a 3/4" riser.



The branch lines could use much smaller vents. If you vent the risers near the top, you may not even need branch line vents.

nicholas bonham-carter

cool video!!

these may be the solution, HOWEVER the system must still be balanced, as well as possible, as later balancing can be trickier, with the valves installed.

an analogy would be if your car brakes are dragging, however instead of fixing them, you put in a more powerful engine to overcome the drag!

remember that these valves cannot call for heat, or fire the boiler, as they are more like the new antilock brakes which will slow down that one slipping wheel on the ice

i suspect when you have finally worked the bugs out of the system, the radiators will more simultaneous.--nbc

jpf321

day cycle..not products

actually .. i was referring to looking specifically at the day cycle part of the video .. i wasn't at all trying to suggest that TRVs were a solution in this case. Since Jeremy has mentioned that the rear apts are sunnyside and the front apts are shady. 

c.t.kay

Piping

Check the boiler piping. It is under sized.

Jeremy_16

Question About Additional Main Vents

What is the best way to add the additional main vents? Can I

put them in series on an antler or menorah in the same spot I have my current

main vent? Or is another location more ideal? Which is better: an antler or menorah

set up (or do they work equally well)?



My mains take a 90 degree turn go about 2 feet then take an additional 90

degree turn where the main vent is 6 inches up on a pipe. The main then

continues and eventually goes down into a wet return. (see pics)



Thanks for the help.



-Jeremy

Steamhead

Antler or menorah

will work, as long as all the pipes are pitched so water cannot collect in them. 

Jeremy_16

UPDATE:

We have made a few adjustments to our system that seem to have helped. When we called in a heating company, they told us our boiler was underfired and they upped the nozzle size and made a few other corrections. They also said we did not have the low-high-low fire modulation hooked up correctly. They attached our vaporstat to control the modulation of the fire and put in a pressuretrol to control the operating pressure. That seemed to help a bit, but I decided to follow a lot of the suggestions on this board as well.



I bought some Gorton #2 main vents and placed 2 on each long main to the front of the building along with 1 hoffman #75 that we already had. Each long main to the front of the building now has 2 Gorton #2’s and 1 Hoffman #75. The back of the building (with much shorter mains) currently has no main vents, but the building seems much closer to being balanced. The top floor front apartments could be a bitwarmer (compared to the other front apartments), but they no longer drop to the low 60’s.



My Questions:



1. If I add main vents to the back mains, will it take away steam from the front mains?



2. Steamhead, you recommended 4 Gorton #2’s at the end of the front mains and mentioned that we can vent the main in about a minute at an ounce of pressure. How do we do that if the pressuretrol is set to cut in at .5 PSI and out at 1.5 PSI? Will adding more Gorton #2’s with the current setup still be beneficial? I’m trying to understand why people talk about venting at one ounce of pressure when most systems do not even run that low. Can someone explain this to me? Should I still add the same number of Gorton #2’s with my current pressure settings?



3.   We created a menorah setup as shown in the pictures below. It was difficult to obtain pitch on one side of the menorah. If the pipe is about level will that be ok? If it were slightly back pitched would the vent not work at all? It doesn’t seem like that much water could puddle up in a ¾ inch pipe even if it was only level.



Thanks for the help.

Steamhead

When you say

"each long main to the front of the building",



does this mean you have two sets of the following........



"11' of 4" at 0.9 cubic feet per running foot is 0.99 cubic feet.



70' of 3" at 0.5 cubic feet per running foot is 3.5 cubic feet. Adding the two gives us 4.49 cubic feet of air. "

Jeremy_16

Steamhead:

The first 11 feet of 4" pipe is shared and then the main splits into two different branches that head to the front of the building. Each branch is 3" pipe and about 70 feet long each.



I think the thing confusing me is the venting capacity chart from Balancing Steam Systems by Gerry Gill and Steve Pajek. It seems that at higher pressure, air is vented more quickly. Is that right? If so, why do we use the one ounce scale? Maybe I'm just missing something.

jpf321

venting...

please remember that vents are always open until they get steam to them and that pressure doesn't increase until vents are closed .. therefore a system will always, or almost always, be at 0oz/in at startup and will be at 1oz long before 8oz and will only get to 8oz once vents have already done their job and are now closed in the presence of steam. hope this helps.