Cold rooms at furthest pt from boiler. Solutions?

Jells

My tenants are still complaining saying it was under 60 in their bedroom last night! The graph shows no clear vent failure artifacts. The graph I posted from earlier in the week showed the index riser to the thermostat and the furthest riser peaking perfectly simultaneous, which in theory means my venting is correct, right? I don't recall what the port is on that radiator in the thermostat room, but it looks like my only tool left is to close down its port more.

neilc

slow the venting where the thermostat is for slower thermostat satisfication,longer run time,
speed up the cold bedroom for more heat, during the runtime,
has main venting been discussed and looked at?

neilc

Jells said:

@neilc Problem is I don't really know what pressure it was, the gauge was frozen at 12. But if the venting is so wide open the new 3psi gauge doesn't budge, how was it ever building up enough pressure to jam the vents? The Ptrol just cuts the flame if pressure gets too high, right?

is there the possibililty that the boiler is too small?
have you calculated the building EDR and compared it to the boiler spec?

or is the boiler older? and possibly leaking up the chimney? and not building pressure?

have you tried pulling the vent from the far cold rad and starting the boiler and seeing if steam gets there? I could see making up a small manual ball valve to replace the vent so you could do this as a one man show, start the boiler, go open the manual ball valve, and you can close it when or if steam arrives, (instead of hustling back to the boiler switch).

sorry if these are redundant, I didn't go back and reread the whole thread

Jells

@neilc the main vent for that front bedroom, a Gorton 2, is behind a wall in a basement apartment so it's a little problematic to screw with unless I'm certain it's having issues. The nice synchronous cycling that I showed this week seems to indicate that the main on that line is just fine.

Right now I'm looking at another odd artifact. The master bedroom radiator on 1 is cold 40 minutes after the riser next to it went hot. The vent was a MoM with no port in it! I just swapped it out for a Hoffman 1A with the cap taken off. The valve is definitely open, I don't have a theory for what is failing in this radiator. Can the shut-off valves clog?

neilc

if you had that pressure up from that other picture, before you checked the pigtail,
then you may have damaged vents, they might work, sometimes, and stick other times,
see if that new vent helps master,
might want to get eyes on the main under it,
what about that EDR question?

Jells

neilc said:

, what about that EDR question?

The boiler is from 2012, sized & installed by a former member of HH, J-Star. I think he knew what he was doing.

Zipper13

I think this was already mentioned, but here's my two cents: my thermostat is in the same room as the first radiator on the loop. The last couple winters since we moved in, the spare room upstairs and the kitchen on the first floor were ALWAYS freezing. both are the two last radiator in the loop This year, I insulated the steam mains in the basement and poof!, the spare room and kitchen rads heat in step with the other rads! those rooms are far more comfortable now. I was skeptical of the benefit, but it's been worth it in comfort so far. not sure if you're insulated, but if not I'd start there - materials aren't dirt cheap, but it's a relatively cheap DIY step to take if you haven't already.

Jells

I'm still wondering about the notion that zero detectable pressure is not a problem in the system distributing properly. My gut says that it's a little like keeping a bicycle upright when you're not moving.

I put the smallest possible port on the MoM in the thermostat room. it seems to have lengthened the cycle from hour and a half to two hours, but the first floor radiator in the front bedroom is still only getting half warm despite the riser next to it that it's on being hot.

neilc

now I'm gonna ask why such a long run time?
are you doing a night setback?

or I'm thinking you need to look into that main vent you can't see, and the others, start with the speed venting again

Jells

neilc said:

now I'm gonna ask why such a long run time?
are you doing a night setback?

or I'm thinking you need to look into that main vent you can't see, and the others, start with the speed venting again

The runtime is solely an artifact of the room with the thermostat and a rad with a MoM #4. It lengthened when I changed it from a 5 trying to lengthen the time to get steam up to the 3d fl.

The closer I look at this the less sense any of it makes. I feel this zero detectable pressure thing is a problem not a good thing. How can steam get everywhere when there's no pressure at all? I took off the vent of the 1st fl bedroom rad today as a heat cycle started, and watched the the temp climb in the riser pipe next to it and it ever so slowly start to move through the rad. I put a piece of cellophane in front of the hole and it wavered intermittently, it sure wasn't getting a steady blow.

So I was still watching my rads and risers during that same heat cycle, and the 1st fl LR rad is hot while the riser next to it is still cool. It's just starting to warm when the boiler shuts down. Huh? I check out the boiler and it's definitely off due the thermostat, but the thermostat room never got heat! ****?

From this graph, it can definitely be said its not the main vents, the furthest main is now ahead of the closest. There's no longer missed cycles. I'm not sure about the temp difference, but it may simply be the 2 different models of the Engbird puck. Both are simply taped to the riser. I have 2 sensors of a different make arriving tomorrow.

Jamie Hall

First place, it is pressure difference, not pressure by itself, that drives steam heat. Most residential steam heating systems which are adequately vented will operate on no more than 1 to 2 ounces of pressure at the boiler, until the radiators are filled.

Now. Doing some pretty off the wall guessing here, but what I'm reading suggests that yes, you have adequate venting -- for the boiler. Second, based on that run time, unless it is a big setback -- 5 degrees or more -- you don't have enough heat input into that room, never mind any of the others. Third, though the boiler was sized and installed by @JStar -- one of the better men, in my opinion -- has anything -- anything -- changed anywhere in the system since he did the sizing and installation? Fourth, how much water are you adding to the system? How often?

Bottom line -- the various problems you are mentioning look very much like you simply aren't generating enough steam to feed the radiation -- or that some of what you are generating is going somewhere it shouldn't.

Jells

@Jamie Hall no, nothing has changed. Which room are you saying is short of heat, the 'index' room? Maybe I don't understand something, but isn't the long cycle is totally an artifact of my using the tiny #4 port? If I opened up that 'index' rad the cycle would speed up. What is considered an optimal cycle time?

What part of this do I have wrong: If in any given cycle the furthest rad is not getting filled with steam, assuming the main vents are adequate and the rad vent is functioning, I can open up it's port, close down the index port, or both.

bburd

Have you clocked the gas meter to see if the boiler is getting its full rated fuel supply? Low gas pressure can cause the symptoms you describe. This can be caused by problems with the gas company’s system or with the meter, regulator(s) or gas valve.

As @Jamie Hall said, it sounds like you are not generating enough steam to fill the entire system, a problem which typically means the radiators closer to the boiler get enough heat, and those further away do not.

ethicalpaul

The pressure is there, but your meter is too coarse to see it. Force a big recovery and see if your radiator vents all close. Some time after they all close you may see the pressure rise. Get a gauge with a scale of a couple inches of water column if you want to see the pressure.

BobC

sagging gas pressure can be a problem.

A few years back i became concerned about my gas pressure, it turns out the pressure was deopping from 3.5 to 2". The gas company ended up running a new pipe into the house - problem solved.

Bob

Jells

Surely some math could determine if I have a BTU problem. Like how long it takes to get to the furthest riser from time of heat call. I ask again, what is the optimal cycle time?

I realize I didn't answer the question about makeup water. I do not know as it has an automatic fill. The last tech suggested changing to one that meters the water.

There's surely something I'm not getting here. This can't be this complicated with unlimited variables. If this were my house like most of you I could fiddle to my hearts content, but this is a 4 family rental during covid, there's only so much fiddling I can do in people's apartments.

Far larger buildings than mine are steam heated, this must be soluble by some means other than the traditional oversizing of the boiler and open windows in most of the building.

Jamie Hall

Jells said:

Surely some math could determine if I have a BTU problem. Like how long it takes to get to the furthest riser from time of heat call. I ask again, what is the optimal cycle time?

I realize I didn't answer the question about makeup water. I do not know as it has an automatic fill. The last tech suggested changing to one that meters the water.

There's surely something I'm not getting here. This can't be this complicated with unlimited variables. If this were my house like most of you I could fiddle to my hearts content, but this is a 4 family rental during covid, there's only so much fiddling I can do in people's apartments.

Far larger buildings than mine are steam heated, this must be soluble by some means other than the traditional oversizing of the boiler and open windows in most of the building.

Indeed, some math could determine if you have a BTU problem. And it's all addition and table lookups. Find the EDR of every radiator (that's the table look up). Add them up (that's the math). Compare that to the square foot rating of the boiler (that's also math -- an inequality/logic). Square foot rating equal or greater than EDR? OK. Square foot rating less than 1.3 times the EDR? No good. In between? Problematic, but with good venting and thorough insulation, works. Now compare the gross BTUh rating of the boiler to the firing rate, converted to BTUh. Firing rate less than gross BTUh? Adjust the square foot rating accordingly and recheck the EDR/square foot inequality.

The question on makeup water wasn't just for fun. If you have a serious steam leak, the makeup water will show that -- and it can account for all your symptoms. You need that number.

There are not unlimited variables. From the thermodynamics point of view, there are, in fact, only two: steam production rate and steam consumption rate (condensation). From the plumbing/distribution point of view -- assuming adequate steam production -- it's a matter of arranging the venting and piping. Not that hard, and well understood.

None of this is hard, but you seem to be lacking in some of the most fundamental parameters here.

Jells

J-Star did all that calculation and I'm going to assume that he was competent and did it correctly when he sized and installed the boiler.  Perhaps I do need to put a metering makeup water valve on. I still do not know what my target cycle time should be at a given outdoor temp. 

But I disagree with there being limited number of variables. Just the fact that if I open up the vent valve of the third floor living room (the one above the index room) it would reduce the length of the heat cycle, and thus the amount of heat going to that apartment's front bedroom, shows that all of this is all very interconnected and interdependent.

PC7060

Per @Jamie Hall - you need to get
some data points, start with the simplest measurement point, gas consumption of boiler versus rated btu/hr. 

1. Read the 1/4 foot dial to determine gas usage over 1 minute when firing (1 full rotation = 1/4 cubic foot gas). 

2. Multiply the cft/min * 60 to get cft/hr 

3. Multiply cft/hr value * 1032 to determine BTU/Hr

4. compare this value to the rating on your boiler to make sure the boiler is running at rated value. 

Post the results. 

Jamie Hall

I don't disagree that steam systems -- and indeed pretty much any system more sophisticated than an open fire -- are at some level complex and interconnected, with a number of minor variables.

And I also expect, from what I know of the man, that @JStar 's work was excellent and accurate.

Which, however, does not mean that a) there are only two fundamental variables at play -- heat input and heat output -- and b) those variables don't appear to have been given any serious consideration, despite the fact that both of them are easily determined. Concern about cycle length etc. and etc. is all very fine, but until those two fundamental variables have assessed is pure window dressing and of no value at all.

Jells

I did the BTU count. 8 cu ft in 3.5 min, works out to 142k BTU/hr. Seems reasonable. But there's no obvious set firing rate on the boiler, it looks like the EZ-Gas burner can be tuned from 50k to 275k/hr.

bburd

@Jells ”Reasonable” compared to what? Since it appears you do not know the connected radiation load, but the boiler was sized by a respected steam specialist:

What is the boiler’s nameplate gas or oil input / firing rate?

Jells

bburd said:

@Jells ”Reasonable” compared to what? Since it appears you do not know the connected radiation load, but the boiler was sized by a respected steam specialist:

What is the boiler’s nameplate gas or oil input / firing rate?

Problem is he installed an aftermarket burner on the boiler. So there is no 'nameplate' rating that I could find looking all over the boiler body. Just a BTU range on the burner.

bburd

The burner installation should have nothing to do with the rating plate attached to every boiler at the factory by code. But if it’s not there, it’s not there.

If you know the boiler model, you can get the capacity data from the manfacturer’s website.

Jells

I guess I'll look harder. Pic is on the 1st page, where would I look?

bburd

Probably on the right or left side of the boiler jacket. The rating plate is hard to miss, usually about 6” x 6” and riveted or glued on. 

Boilers designed to burn gas often have a sheet metal cover over the burner and controls, which must be removed to see the nameplate; but your boiler does not appear to have a cover.

neilc

or you have your calculated your btu usage, input,
*80% steam efficiency, = BTU output , , ,
vs the EDR calc for the building ,

someone correct my math and algebra,
142k BTU/hr / 240(?) = EDR(?) at 0.59(?), well this can't be right, but you get what I'm thinking

bburd

@neilc We are trying to figure out whether the boiler is underfired. The op clocked his gas meter but does not know the system’s EDR or the boiler rating.

neilc

right,
and we know the input,
but we don't know the asbuilt firing rate, or EDR,
without JStar's notes it seems getting or estimating the EDR is the next step.

go back to my algebra, if my numbers are correct, then firing rate / gas consumption is low, very low
I am not confident in my algebra though.
(trying to back door into this)

bburd

A steam boiler firing gas at 140,000 Btuh can support a radiation load of about 350 ft.² EDR, assuming insulated steam pipes (standard 1.33 piping and pickup factor) and nothing unusual in the installation.

neilc

IDK where I got the 240 from,

bburd

140,000 Btuh input * 0.80 combustion efficiency on gas / 1.33 piping and pickup factor = 84,210 Btuh delivered to radiators / 240 Btuh per sq ft steam EDR = 350 sq ft. 

neilc

and I still hate algebra

and math,
and reading comprehension,
and spelling,
and

neilc

neilc said:

someone correct my math and algebra,
142k BTU/hr / 240(?) = EDR(?) at 0.59(?), well this can't be right, but you get what I'm thinking

it was that stupid little "k",
and all those zeroes, and then some,
goodnight

Steamhead

Jamie Hall said:

You're not the first to break a sight glass. Why people learn to always have a spare before they mess with it.

The glass won't break at all, unless you DON'T have a spare!