Radiators not heating

charlie83

I need some help/advice figuring out why some of my radiators not heating up.

I have a new steam boiler installed over the summer. One pipe system. Everything pitched right. All new near boiler piping with drop header. New main venting. New vents on rads.

I started boiler up and let it run to check balancing before winter. Only a few of radiators get hot. I can’t figure out what is wrong. I took rads off to check the valves. They open and close but they don’t look like they are all the way open. How far up is the seat holder connected to the stem supposed to go up? I looked inside and they are open but look low (see pics). I can barely fit my finger in between the opening. Could this cause radiator not to heat? Should I change the valves?
There is very little sludge inside the radiators. And I removed the vents to check for blockage but they are free of blockage.

Any suggestions or advice is much appreciated.

STEAM DOCTOR

Did you have this problem with the old boiler? Have you tried to clock the gas meter?

charlie83

We just moved in few months back. This will be first winter. Don’t know if they all worked before. How do you clock the meter? What purpose does that serve?

nicholas bonham-carter

Take the vent off the cold radiator, and turn up the thermostat.
As it starts from cold, listen for unusual panting from the vent tapping, indicating a low spot trapping water which the steam is struggling to get through.
Also tell us about your main (not radiator) vents, as well as the setup of your thermostat, (is it set for steam)?
Pictures and details of your boiler will help as well.—NBC

JohnNY

You could clock the gas meter to make sure the boiler is taking in all the fuel that is necessary to make steam. When I come across this, I'm immediately suspicious of the size and output rating of the boiler itself. A wide picture of the boiler and close-up of the ratings plate/sticker would be very helpful for a start.

1Matthias

Question..I know you said that you replaced the main vents, but what size vents did you replace them with? This almost sounds like an undersized venting issue and/or a boiler size issue.

JUGHNE

In your other posting you calculated your EDR with help from Fred and based the boiler size on that 450 EDR number??

You might have a low gas pressure problem and/or air venting being under sized.

charlie83

I have 2 big mouths on 2” 62’ main. 1 big mouth on 2” 40” main. Boiler was sized to edr. Haven’t clocked the gas meter. I had opened wet returns via unions thinking maybe they are clogged but they aren’t clogged. A little sludge but not clogged. Thermostat is a Honeywell TH4110D1007. I do know the boiler short cylcles, on for about 5-10 mins then shuts off. Could that be that the thermostat needs to be changed to a different one? I have pressuretrol set cut in .5. Should I worry about the 80yr old radiator valves. They seem to only open half way from what I see.

Fred

The valves look to be open to about normal. Do you have any gate valves on the mains, that were installed as part of the new near boiler piping? If so, are they open or closed? They should be open. The fact that you say the boiler short cycles for 5 to 10 minutes and then shuts off is concerning. How long does the boiler run before that happens?
Also, make sure the Thermostat is set (or programed) for steam , 1 or 2 cycles per hour. They come from the factory with a default setting for forced air which is 5 cycles per hour. If you have the manual for the Thermostat, look up how to change that setting. If you don't have the manual, google the model number and download the owner's manual.

JUGHNE

You need to determine if the short cycling is because of the T-stat or the pressure control. Can you see any pressure shown on the gauge?
Your T-stat guide may have a section called installer setup; I am looking at the TH5000 series, a step up from yours, but perhaps the same basic setup.
System type may be the first item...heat only #2.
Then stage 1 heat cycle (cycles/hour)…..try #1 for steam systems.

Check that and let us know, please.

charlie83

So I changed the program to steam on thermostat and that seemed to do the trick. All radiators are heating now. But it did short cycle 1or 2 times when I initially started boiler up from cold. But it has been running for longer allowing steam to reach all the radiators. The 0-30 gauge has been pinned to 0 the whole time. Could the gauge be toast?

I clocked the gas meter. 3 times I clocked 11 secs on 1/2ft. Input on boiler plate is 177k, and output is 147k. Is it over or under firing?

JUGHNE

The 0-30 gauge was toast when it was still in the box, worthless for the application but code requires a gauge that will register double of the pop off relief valve.

You are better served by a 0-3 PSI gauge from WIKA #33020 from the gaugestore.com. It needs to be on a pigtail to guard it from direct steam contact. Leave the 0-30 in place.
Could we see pictures of your boiler installation?

3600 X .5 (dial size) X 1050 (approx. BTU content of 1 cubic foot of NG) = 1,890,000 divide by your time of 11 seconds =
171,818 BTUH input. (Provided this was the only appliance using gas at the time.)

So you are close to your 177 input.
I would guess this is enough for your application as most rads were oversized for the job.

Is your piping insulated and did you have this checked by someone with a combustion analyzer.

Pictures?

Fred

@charlie83 , are you sure the boiler is short cycling? Do you have a Cyclegard Low water Cut off on that boiler? If so, that unit will shut the boiler down periodically for a few minutes to check the water level. That is not Short cycling, it is the design of the Cyclegard, which is why most people switch them out for Safegard units.

New England SteamWorks

Also: Was the boiler skimmed? If not, priming and surging can cause steam to move (or not move) in unusual directions and cycle the low water cut off

charlie83

Fred: yes there is a cycle guard lwco. Should I change it to a different one? If so, which one? Is that something I can do on my own? I would assume the boiler must be drained first to do that.

New England SteamWorks: boiler hasn’t been skimmed yet. When I skim it, should I wait for boiler to get hot but not steam, open skim port, and add water slowly?

Fred

@charlie83 , That Cyclegard is probably a part of the reason the boiler shuts down and seems like it is short cycling. You don't have to drain the boiler to change it out. The Safegard does not shut the boiler down like the Cyclegard does and most people use the Safegard. The Probes are the same so you just have to change out the box and leave the probe in the boiler. If you replace it, just be sure to get the one for your voltage, (either 24 volt or 110 volt).

Skimming the boiler is very important to getting the water level to stabilize. The water in the sight glass shouldn't bounce more than 1/2 to 3/4 inch. You may have to skim multiple times to really clean it out. Heat the water up, fill the boiler until water starts to trickle out of the skim port and let it trickle (very slowly) for as long as you can, at least a couple or three hours. Repeat as necessary.

hboogz

charlie83 said:

So I changed the program to steam on thermostat and that seemed to do the trick. All radiators are heating now. But it did short cycle 1or 2 times when I initially started boiler up from cold. But it has been running for longer allowing steam to reach all the radiators. The 0-30 gauge has been pinned to 0 the whole time. Could the gauge be toast?



I clocked the gas meter. 3 times I clocked 11 secs on 1/2ft. Input on boiler plate is 177k, and output is 147k. Is it over or under firing?

How did you clock the gas meter? Would love to know.

Also, did you change your T-stat, or adjusted this one ? Honeywell TH4110D1007 ?

Glad you got it working.

Harry.

BobC

To clock a gas meter follow these instructions

Bob

charlie83

@hboogz I clocked the meter how @BobC attachment shows. Just make sure all other gas valves for appliances are shut off. And I changed the setting on the tstat to steam, and changed the lwco to a safguard. No more short cycling. I also skimmed the boiler for a few hours. Water was coming out clear and Sight glass was clear by time I was done. But now sight glass in a little murky again. Probably need to do another skim.

hboogz

BobC said:

To clock a gas meter follow these instructions

Bob

Thank you @BobC

hboogz

charlie83 said:

@hboogz I clocked the meter how @BobC attachment shows. Just make sure all other gas valves for appliances are shut off. And I changed the setting on the tstat to steam, and changed the lwco to a safguard. No more short cycling. I also skimmed the boiler for a few hours. Water was coming out clear and Sight glass was clear by time I was done. But now sight glass in a little murky again. Probably need to do another skim.

Awesome @charlie83 Happy that worked out for you and thanks for sharing!