Cold day

FWDixon

Another day below 30 and my house is an icebox. Local HVAC guy came out yesterday to install a new circulator (Taco 007-F5) and pressure relief valve on the boiler. Didn't help with the heating at all, just the new circ doesn't get stuck now.



For some reason, I can only maintain a 35 degree temp difference (indoor/outdoor) max. This is fine when it's in the 30's, but when it gets any colder the house becomes an icebox.



Before and after the circ change, when it is on the return line is cold and the boiler temp dips below 130 even though the aquastat is set at 160-180 with a 15 diff. The same rads that were half-heating before are still half heating, and all of the rads the bottoms never get hot, just the tops (except for the cold ones).



I'm at a loss, thoughts?

Mark Eatherton

Could be a number of things...

Undersized pump, air bound radiators, undersized heat source, excess infiltration, restrictor orifice plates.



Show us how your radiators are piped first. In the bottom, out the top, in in the bottom out the bottom, or in the top out the bottom.



Was it originally a gravity circ system?



How many square foot of house?



How large a boiler?



What fuel source?



Continually exposing a non condensing heat source to the possibility of condensing is NOT a good thing.



Off hand, it sounds as though your heat source is undersized compared to the connected loads.



ME.

kcopp

I think you are over pumped....

Do the primary loop w/ a 15-58 Then install another one on the primary loop. The primary should be full size. the piping off the main loop should be 1 pipe size less that 1/2 of the main. so if the main loop is 2" your piping off the primary loop should be 3/4"

FWDixon

re

Show us how your radiators are piped first.

In at the Top, out at the bottom

Was it originally a gravity circ system?

I haven't a clue



How many square foot of house?



1451, 26.3' square, 2 floors.



How large a boiler?

Burnham RS-112 with a Wayne P250AF conversion burner. 125MBTU





What fuel source?

NG



Continually exposing a non condensing heat source to the possibility of condensing is NOT a good thing.

I know! I'm really getting concerned about what's happening to my boiler.



Off hand, it sounds as though your heat source is undersized compared to the connected loads.



Other info:

I've done two heat load calcs on my old house, and the average is roughly 56MBTU (Manual J put me between 44MBTU and 49MBTU depending on Tightness, slant fin had me a 64MBTU). I have about 54MBTU of heating area on my existing rads, and about 4750 HDD (70 deg)(Manual J) with the coldest nighttime temp being around 13 on average.

FWDixon

Piping

I only have one loop,



http://www.heatinghelp.com/files/posts/22761/heating%20system.pdf

I have 1" OD pipe connecting the boiler to the original supply and return lines (2.5" OD) The original pipe is reduced on the downstream side of the flow control valve and upstream of the circulator.

kcopp

i know....

you need to re-pipe. I saw the other post.

Mark Eatherton

Time to grab a stop watch and calculator...

It would appear that the boiler is oversized if anything, IF it is firing at its rated capacity (which I doubt because if it were, it would be hot and short cycling).



Using a stop watch with only the boiler running, determine how many seconds it takes for on revolution of the 1 or 5 Cu Ft dial. Take 3600, and divide it by the number of elapsed seconds. Multiply that answer times the volume per revolution (1 or 5) and then multiply that answer times the caloric content of per cubic foot of your natural gas. Take that number and multiply times .8 to determine the output, and then divide that number by the square footage of your home. If it is less than 30 btu/sq ft/hr, someone needs to come and turn the firing rate up on your boiler.



Get back to us.



ME

Gordy

Am I missing something

Hvac guy comes to fix heating system. Throws a couple of parts on. Some needed maybe.



Hvac guy leaves heat still not performing as expected.......is he coming back? Did you only ask to fix the stuck circ, and pressure relief valve.



If he knows system is not performing well, and that you want it fixed, and he is not coming back to fix it after said parts did not help, or he was not thorough enough to do what was needed.......how is he in business?

Mark Eatherton

Not undersized piping...

Your near boiler piping is reasonable.



The rule of thumb is the main pipe divided by 2, and then one pipe size less than that. 2.5" OD = 2" ID, divided by 2 = 1", next size down is 3/4" (1" OD).





ME

FWDixon

Re

This is all being run through a home warranty company, so there are no guarantees as to what they will pay for. For example, they covered the pressure relief valve but not the air vent (which has corrosion on the pipe and the tech wanted to replace) because it is attached to the plumbing and not the boiler directly (but so is the pressure relief valve). Also, I have a feeling they contracted the cheapest person they could because the HVAC company never returns calls or shows up when they are supposed to (called them today to let them know we were still cold, and they said a guy would be out at 2, never showed, never got a hold of them again).



Unfortunately, I'm having a hard time finding a knowledgable radiant heating company in my area (locator tool on here and on hvac-talk returns no results, yellow pages don't have any either). Ultimately, I am probably going to have to call in some favours through my cousin who is a plumber, but I want to know where to point him before hand (I can get work from him for parts only, as I can swap labour with him on jobs).



The warranty claim was boiler firing but rads cold.

FWDixon

Timer

Thanks for the tip, will do this when I get home from work and report back.

I agree the boiler seems as though it is oversized and should be more than able to handle the load....



Note to self, next time there are CI rads in a house, get a qualified tech to check out the system before closing.....

FWDixon

Pipe

Ah, makes sense. Your response was a little too germane to that other thread to be coincidence



Will re-read your post now that I understand why you made it.

FWDixon

OK

good to know. It's the smallest piping on the system as well as the newest, so I wasn't sure.

Gordy

Okay I see

Was there a home inspection done before sale?

FWDixon

Yes

There was, and the inspector reported no problems with the boiler, but as it was mid summer he didn't check the heating system.



What I found shortly after closing was the aquastat was set to 140 hi and low, dust in the blower on the burner, debris in the flue, and that all the data plates were painted over, which made me start to question a lot of things with the system.

Mark Eatherton

Somethings not right with your drawing...

I've not come a cross a down feed gravity system in hydronics. Not to say it doesn't exist, but a quick check of Dan;s library didn't produce a drawing for it. (EDIT: FOund this on the site http://www.heatinghelp.com/article/332/Gravity-Hot-Water-Heating/72/Gravity-Hot-Water-Heating-FAQ



Your drawing still looks like a one pipe monoflow system.



Questions: How old is this house, and when did electricity come to your neighborhood, and where are you located?



END EDIT,



http://www.heatinghelp.com/files/articles/1206/347.pdf



If in fact it is piped the way you show, it is more likely a monoflow or diverter tee system.



Are you positive about the drawing?



ME

Harvey Ramer

My experience

with the style heat exchanger that you'll find on the RS boiler is that when they start condensing on a high mass system, it will virtually stall the heat transfer. Enough so that it doesn't catch up.

Should add a boiler protection valve.



That piping is really strange. I don't really believe it can work with forced circulation unless you do some repiping. Or slow the flow down to a snail's pace, literally!



Harvey

FWDixon

Keep in Mind

that I did the piping diagram off of a what knowledge of gravity systems I had and crawling around in the attic and crawlspace and inferring what was in the walls based on the layout of the radiators, so it may not be 100%. All I can say for sure is that the supply goes up to the attic from the boiler, branches out to each of the 4 upper rads, then upper and lower are connected somehow, and then each of the lower rads have a return that comes back together in the crawl and then to the boiler. There is another smaller pipe teed in to the return near the boiler that appears to be the return for the upstairs bath, so I guessed the office also used a similar dedicated return pipe that tee'd in to the main return pipe (I'll check this next time I'm in the crawl, it's a tight fit for a guy my size).

I can hear water moving through the pipes now when the circulator comes on, whereas with the old pump I had to place me ear on the pipe (that was comfortable when it was cold, but got painful quick on the hot pipes), so the new circulator I presume is moving water at a great flow rate than the old one, which is not what I want it to be doing. I am almost wanting to pop the flow valve open and turn the circulator off and see what the system does using gravity only, but worried about damaging the boiler.

Harvey Ramer

A better diagram

would help a lot. As accurate as you possibly can.



If it was indeed a gravity system with the supply going into the attic and then branching off and feeding down to the radiators, there was most likely an expansion tank located in the attic. If they converted it to a pressurized system they most likely removed it. Look for a pipe sticking up and capped off. Remove the cap and install an air eliminator in that location. Then you either have to turn the system pressure up to 18 to 20lbs or move the circulator to the supply side pumping away from the expansion tank.

The top of the system could be airbound, especially the office zone... if the diagram is accurate?



Before you make any changes though, verify all information and testing procedures that Mark and the other Pro's asked you to do. They are all very important.



Harvey 

FWDixon

Any idea

how to determine the route of the pipes through the walls without cutting in to the walls?



I was thinking a non-contact thermometer or better yet a thermal imager (I have the former, want to buy the latter but need to save up).

Harvey Ramer

If you

look at where a pipe goes into a wall and where it comes out of the wall, you can get a fair idea.



Harvey

Mark Eatherton

DO that….

DO open that flow valve and do turn of the circ. It won't hurt the boiler. See if your comfort conditions improve. Previous owners may have been suffering with the system all along hoping somebody would come by and buy their problems…



These systems were designed around a 30 to 40 degree differential, meaning if you flow out at 180, you would return above 140, which is safe for the boiler.



ME

FWDixon

Calculated BTU

I got about of 18 ft^3/sq ft/hr. That may explain a lot.....

FWDixon

I am not

100% on the drawing, or that it's a converted gravity system (as that doesn't jive with the time of the house) but a downfeed was the only thing that even resembled the way the visible parts of my system were plumbed and someone told me that it sounded like a gravity system. I initially told it was a monoflo on another site, then they said monoflo wasn't around in the 30's. The branching piping in the crawl and attic also didn't match the monoflo diagrams I could find.



Anyway, except for how the top and bottom floors are connected, I am fairly certain on the drawing as the branching pipes are visible in the attic and crawlspace and line up with the rads on the repsective floors.



The house was built in 1939, electricity was available at construction, and was built for shipyard workers at the local navy yard.

Mark Eatherton

Problem with the drawing is...

You show the supply coming down from the ceiling, going into the radiator, then coming out of the radiator and connecting to the supply line again. It (radiator return) should be connected to a return line.



Without having any diverters, the water has no real incentive to flow through the radiators.



Water is wet lazy and stupid. It is ALWAYS going to follow the path of least resistance in its efforts to get back to the circulator.



I'd seriously doubt if this was built as a gravity system. I think this is a 2 pipe parallel reverse return down flow system, or a diverter T system and it has always had a pump. 1939 was WELL into pumped systems. But, I've been wrong before… and I plan on being wrong again :-)



At one point in time, there were numerous diverting tee manufacturers on the market. The most prominent one was by Bell and Gossett, but Thrift, Taco and others also made them, and some of them were not as obvious as the MonoFlow T.



Is this system piped in iron pipe or copper tubing?



ME

FWDixon

The pipes

are all iron.



i do know that there is some means by which the supply and return are connected parallel to the radiators as with all the rads turned off i still have flow through the system (this was discovered when the system was flushed).

Ironman

Location?

Where are you located?

FWDixon

i'm in

Portsmouth, VA

Ironman

System

Is this the type of system you have. It's called an "overhead system".



You can find it by clicking on the "systems" tab above and going to "gravity systems - FAQ".

Ironman

Thought So

I thought so when you mentioned the Naval yard. I'm near Staunton, but I don't know of a good hydronics man near Tidewater. Let me do some asking around with my reps and see if I can find someone. You're a little far from me and we're enjoying about 20+ Inches of snow right now with more on the way this afternoon.

FWDixon

thanks

i know you guys are getting creamed up there. thanks for being willing to do that for me, the tech just left and said the boiler need replacing, the flue's too big, gas conversions don't work, the cold rads need replaced with baseboards, and the whole system is done wrong. luckily i've read enough to know that isn't the way to proceed, but damn it's getting frustrating....lol.

FWDixon

i don't know

i thought so, but Mark here has me wanting to go through the system from top to bottom and verify my system schematic.



It may well be some type of monoflo-esqu set up, or something else entirely. I'm going to tackle that over the weekend.

Harvey Ramer

Even with

the radiator valves all shut off, if it is any type of single loop diverting tee system you will still have flow through the system.



Harvey

FWDixon

Second Opinion

Finally got a hold of a guy here who has 35 years experience with oil and gas boilers. Talked him through what I had going on and he said 2 things:



1) He definitely thinks we should be able to get heat to all the radiators

2) We can repair what we have and make the system work, but the RS-series and Wayne conversions are not worth throwing money at to fix if replacement is an option. He recommended a Utica MG-series...only down side is that the utica doesn't have a DHW coil so we would need to buy an external water heater (I would like an indirect at some point).



He also is willing to come by the house and take a look at the system to give us a better idea of what our options are (repair or replace, service and maintenance on exisiting components), and recommended a local plumbing company that has the necessary experience and licensing to do NG stuff (apparently he has all the oil licenses, and will configure the boiler, but can't do NG connections)



So progress....ish. Ultimately it's up to the warranty company, and a new p250AF is a lot cheaper than a couple thousand dollars worth of new boiler stuff.

Ironman

Be Careful

If that is indeed an old overhead system, you can't just go throwing in a pump and a new boiler - particularly a mod/con. The flow in that type system is crucial and adding a circ(s) can mess it up. That may be your problem now.



Just because someone has 35 years experience doesn't mean he understands that type of system.



Mark has that much and is one of the top hydronic experts in the country and he said he never had worked on one. I've got over forty years and have only dealt with one and we work with old gravity systems frequently.

FWDixon

Duly noted

I'm just happy to get a second set of eyeballs on the house. I still have to get up in the attic and look for where the expansion tank would have been originally if it was a gravity system. It is entirely possible it never was a gravity system at all. I have no way of knowing without getting input from you guys (which I'm extremely thankful for btw)

Ironman

Pictures

Any pics of the system would be very helpful.

FWDixon

I will

Break out the nice camera and take a plethora this weekend. Can't wait to squeeze into my crawlspace....it's about 18 inches high, I'm about 16 front to back....

Harvey Ramer

While you are at it,

get some good pictures of the Tee fittings in the system. Might have to pull away some insulation. Where a dusk mask of course. Label each tee and show us the flow directions through them.

 I know it's a tough job but it's not as tough as the dead men had it to put the pipe in. If you think about that while you are worming through the crawlspace it might make it easier.



Harvey

Harvey Ramer

What Ironman said.

You can't force the issue with these systems. You would be ill advised to spend any money till you know exactly what you have.



Harvey

FWDixon

Tees

Unfortunately the only tee's I will be able to access are the ones on the main supply and return lines. All the tee's that actually connect the rad pipes to the supply and return pipes are buried in walls.