Radiators running cold after service

mramirez

Hello everyone,

one pipe steam system. 

Two mains, 40’ and 20’
(Attached a diagram)

i recently purchase a home and noticed that the radiator in bedroom 1 was cold. 

I called a local contractor for service and by the time he left I had 3 cold radiators.he also raised my pressuretrol main to 5.

That led me to this forum and getting to know my system and trying to fix it myself.

I lowered the main to 1 and diff to 1.5

I replaced both main vents from Gorton 1965 to a gorton #2 on my long main and a gorton#1 on my short main.

I replaced all radiator vents to maid o mist. Except for the kitchen which has a Hoffman 41.

Short main has been running beautiful. 

On Saturday after 3 hrs of the system running  I got heat to the cold side. All three radiators were about halfway hot. But as soon as I lowered the heat they were the first to go cold.

Yesterday I raised the entryway and bedroom radiators 1/2” with a pitch and ended up hearing gurgling and water hammer at the start of the heating cycle. 

Tonight I will check the level of all the pipes with a pitch. 

But hoping to hear from the community on possible fixes. 

dabrakeman

My first question would be what did the service guy actually do when he came? You said you had one cold radiator issue before he came and 3 when he left.

It sounds like you took some reasonable first steps improving your main venting and lowering the pressure settings. Pictures of your boiler and near boiler piping taken from a distance back and a few angles is always helpful so all can understand what you are working with. Also take a photo of your pressuretrol showing the settings. Pressure should never go over 2psi and that only after all the radiators are full.

- Do you know if your 40' main is all counterflow (rising continuously from the boiler to the end of the main or parallel flow (highest point is at the boiler)?
- Anything going on with pitch between the living room radiator and the entryway? Some pictures of the main along this area would help. The fact that all the cold radiators are in a row (last three on that main) would make one suspect something in this area.

Generally radiators being cold are due to water being trapped somewhere blocking the steam. Need to look at it that way and see where this might be possible. Boiler could be undersized (unlikely) or underfiring for some reason. Do the flames look strong and blue from the burners? You could compare your total sqft radiation to the boiler size as a sanity check but I would first follow the steam and condensate paths.

ethicalpaul

First, good job getting your pressure and venting improved and recognizing the bad service you received from that guy. Based on your description, especially your statement that after you raised a radiator you could hear gurgling, here's my shot in the near dark:

- You have an area where the main pipe is sagging and collecting water. That was preventing all steam from passing that point
- When you run your system for a LONG time, eventually the water will get "steam hot" and steam will actually start to pass through it as the trapped water stops being able to condense all the steam that is hitting it
- After you raised the radiator, it possibly lifted the main a bit and made the trapped water be less, more easily allowing the steam to eventually pass. The gurgling sound is a dead giveaway that you have a water trap either in the main or maybe in all of the affected radiators' supply piping.

You need to find any areas of your main (and potentially also the radiator supply lines for those cold radiators) and correct the pitch so that there are no sags that can form these water traps.

Based on your partial success with raising the one radiator, I would attempt to raise more radiators on that main to try to correct the sag from above. Start with the cold one closest to the boiler (on the main, not as "the crow flies". Or depending on what's going on the one previous to that might affect things!

Raise it like 1/2" and then call for heat and see if you can hear or feel air escaping from the radiator's vent. The MoM "D" size vent is massive, so if you eliminate the water trap you should have NO PROBLEM feeling the air escape from that vent at the call for heat.

You can even put tape on that main's #2 main vent to better force the steam to your radiators to save time. As you call for heat, monitor each of the radiators on that main line. While you are there, start a call for heat and see if any air is even escaping from that Gorton #2 when the boiler starts making steam.

If/When you are getting steam to that first cold radiator, then try lifting the next one, and so on. If your main is readily accessible from below, you can also check the pitch and look for the sags from there, or in some combination with the "from above" approach. It's just that lifting radiators a little bit and checking is pretty easy--doing that from below might be more challenging depending on the basement.

I experienced this same issue in my house where the settling of the house created such a trap, but luckily for me it was only on a single radiator supply pipe and I was able to relatively easily re-run it and abandon the trap in the floor. If you're in NJ I'll even come over and help.

neilc

along with boiler pictures,
post a picture of the rad you lifted,
show both ends,
along with lifting the rad, you also want to lift the vent end of the rad so the rad itself pitches back down to the supply valve and pipe,

mramirez

My first question would be what did the service guy actually do when he came? You said you had one cold radiator issue before he came and 3 when he left.-The service guy changed the rad vents with hoffman 1A, but mentioned to not worry about the dials because the numbers dont mean anything. Then he said i raised your pressure to 5 because it was "...too low for this type of system."
He spent about 3 hrs in the basement banging on pipes. unfortunately, i could not focus on him as my house was gettin kitchen cabinets and insulation removed that same day.


- Do you know if your 40' main is all counterflow (rising continuously from the boiler to the end of the main or parallel flow (highest point is at the boiler)? 40'main is parallel flow.

- Anything going on with pitch between the living room radiator and the entryway? Some pictures of the main along this area would help. The fact that all the cold radiators are in a row (last three on that main) would make one suspect something in this area.-I will attach pictures in the next post

mramirez

Attached are the pictures of the main vent.
I raised the cold radiator in the entryway 3/4 inch with a pitch towards the valve and last night I kept the heat at 72. This morning the half of the radiator remained hot. I also raised the radiator in bedroom1 3/4 inch but it did not heat. 

leonz

Do you own an eight foot bubble level? This pipe does not appear to have any slope.

All you may need is adjustable pipe hangers attached to the joists to carry the pipe and allow you to
to create the correct pitch/rise and run.

Did you put that piece of lumber and wooden block there in the second picture supporting that elbow????????????????

mramirez

I was putting up hangars on the pipes when I stopped to take the picture. I was using the wood for support. 

dabrakeman

Looks like you are on the right track of making sure all your piping is pitched correctly to not trap any water but you might also want to check whether the new Gorton #2 main vent is actually venting and not stuck closed for some reason. You can just quickly take it off and see if you can blow through it.
Usually it is a great vent but easy enough to check.

mramirez

Confirmed the gorton#2 is working.  

my current plan is to raise the cold radiators up to 1”  over the course of two weeks. If that doesn’t remedy the situation, I will begin raising the main pipe over a month. Creating more of a pitch towards the return. 

dabrakeman

You mentioned your 40' main is all parallel flow. So, you have measured with a bubble level that you do indeed have continuous pitch of the main away from the boiler, particularly from radiator #6 (last working radiator) takeoff onward? Unless it is very obvious that you have pitch you may have to take the insulation off temporarily to get an accurate measure (I know, PITA). Raising the rads could possibly take away from parallel flow pitch of the main so be cognizant of that. When you mentioned moving on to "raising the main" again keep your continuous parallel flow in mind so any raising would likely be upstream of the non working radiators.

mramirez

Used a 1’ and 6’ level. Found a pitch issue. My 100 yr old house settled to the right of the picture. 

Moving on to raising the living room radiator 1/2 inch to hopefully raise the main from above. Then going to put up some hangars to assist. Going to move at a snails pace to try and not crack anything.