UPDATE: Is a Vacuum the problem?

matthewb84

Hi Everyone,

Is a vacuum possibly causing a cold radiator?

Please see attached system diagram.

The Living room radiator that 99% of the time is cold sounds like its breathing, in and out sound. Can the 3 lines off the main(closest to main vent) + the single line (closet) create a vacuum strong enough to prevent Living Room radiator from heating? All four of the hot radiators are hissing constantly once hot from either a coupling or steam vent itself. All off the hot radiators plus the main vent are after the living room branch.

Water hammer happens once system shuts down. I am thinking once the system shuts off, the vacuum diminishes and the steam flys up the Living Room line? There is also sometimes a noticeable expulsion of air at this time too.

Is a good way to test this shutting down 1, 2 or 3 of the runs closet to the main vent?

Radiator vents are a mix of brands throughout the years (older house)

Blown Main vent was replaced with a Ventrite #35 (maybe too small?). Main vent blew after high PSI from install.

I am NOT a professional. Hope for a little help!

Previous posts for reference:

https://forum.heatinghelp.com/discussion/comment/1463874

https://forum.heatinghelp.com/discussion/163277/last-year-banging-this-year-short-cycle-help

EBEBRATT-Ed

I didn't read the old posts but it sounds like a pipe without enough pitch on it. Get a level and check the radiator pitch and the pitch of every pipe leading to that radiator

matthewb84

@EBEBRATT-Ed

It's raised up and pitched. I had it higher at one point but didn't see a difference. Looking from the basement I had it up about 1 inch total at on point, with a pitch.

Picture attached.

Thoughts?

Jamie Hall

That breathing sound is often caused by water lying in the pipe feeding the radiator -- which will also keep it from getting much steam. Are you sure that all the "horizontal" segments of pipe feeding that radiator have at least the proper pitch?

And no, it is doubtful that the other radiators can create enough vacuum -- particularly once they are hot. If they have fast vents, though, they can form the easiest path for steam and keep the problem radiator from getting much -- again, until they are hot.

matthewb84

@Jamie Hall

Yes its pitched via level, but I will raise the far side even more in case there is some build up in there.

Your second comment makes sense here, will shutting down 1 or 2 of the Hot radiators make a difference to see if its the easiest path logic?

Another example. Had some friends over Friday night. They stayed in BR #1 and BR #2 respectively. I stayed in the Living room with the door closed, stat is in this room.

System ran for at least 3 hours with BR 1 and 2 guests complaining it felt like Arizona while Living room radiator didn't heat at all.

Jamie Hall

I wasn't thinking of the radiator -- the pipes?

EBEBRATT-Ed

need to check the pitch on the steam main and radiator run out. Sometimes old piping sags and holds water , hangers loosen up over time

matthewb84

@Jamie Hall @EBEBRATT-Ed

Good points, I will check the entire run next. Besides the drop from the 3rd floor (guessing its straight down) there are 3 steps down. 1. the longest just after the 3rd floor drop 2. a short drop to clear the floor joist and 3. the last drop to the main.

I will make sure all are pitched.

Fred

When is the last time this system had any maintenance? It sounds like an array of issues, all of which need to be addressed
- Hissing from vents and Couplings
- vents blown from high pressure
- Banging and panting (means water sitting somewhere in the system)
- A Vent-rite 35 as the only main vent.
Not enough main venting
When is the last time the Pressuretrol was taken off and the pigtail cleaned out? It sounds like it is probably completely clogged and the Pressuretrol can't see the system pressure to control it, OR the Pressuretrol has failed, or is set way too high.
There has to be pipes that are sagging or pitched incorrectly. Radiators can be pitched fine but the pipes are equally critical. There should be no hammer or "breathing" sounds.
Any couplings that hiss need to be tightened or replaced.
Vents should not hiss. They should close once steam hits them.
This is not a vacuum issue. It needs a number of items corrected.

matthewb84

@Fred

Thanks for the help here.

I think main venting is definitely an issue, however, not sure if landlord will get that corrected soon or ever so I will work on the couplings and radiator vents respectively. Hoping that will make a difference.

I am tempted to correct main vent as best I can myself but haven't crossed that line yet.

The boiler was replaced last year including the Pressuretrol. It was set way too high which blew the main vent. It has been adjusted and currently sits at 1.5 with a .5 diff. Is it possible the Pressuretrol is dirty from the recent install? It seems to be working properly with the adjustment and new main vent.

acwagner

Do all your vents "pant" or "breath" or just this one problem radiator?

If they all do, then your boiler might need to be skimmed. That's the case on my boiler. I have a new boiler too and I'm still working to get all the oils/debris out. I know when it's time to skim when my vents start "panting". The water line in the boiler is all over the place by that point.

matthewb84

@acwagner I will check the water glass when I return home Tuesday, before the new main vent was installed It was blowing water all over so the water always appeared clear. It could very well need to be skimmed.

@Fred @Jamie Hall @EBEBRATT-Ed

System operated from a cold start this morning - ran about 90 minutes before I shut it off before work. The four radiators that are usually hot were hot and the living room was cold the entire time.

Once the system was shut off the living room radiator began to heat, you could hear the vent, venting in a constant manner (very different from the up and down during run times) for over 3-4 minutes till it tapered off. The steam made it to the valve and into the 1/2nd chambers in the radiator whereas during the 90 minutes the steam never made it to the valve.

Would it make sense to drop the pressure down to 1 with a .5 diff? Currently stands at 1.5 with .5 diff.

I plan on coming home with tools to fix the leaky joints and valve stems then trouble shoot each radiator vent.

Kahooli

I'd turn one of the bedroom vents upside down and see if the Living room radiator heats.

Also, not having a room heated properly should be grounds for getting your lease terminated depending on your municipality. Talk to your landlord, if they refuse to have the PROBLEM fixed, then look at your options.

Fred

I am almost certain that pigtail that the Pressuretrol is mounted on is likely clogged. I am also certain the boiler needs to be skimmed and that you most likely have a supply pipe to that problem radiator that is sagging or pitched the wrong way (in the basement if this is on the first floor). Those things need to be addressed.

matthewb84

@Kahooli Good point! I will look into it.

@Fred thanks again for the advice. 3rd floor to basement. I am going to laser the run and see if I can find any dips or sags.

Thank you both for your help here.

Fred

If the problem radiator is on the third floor, try raising both ends of the radiator up a half inch or so. That will give you some pitch on any horizontal pipe under the floor. They you you can repitch the radiator

matthewb84

Hi Everyone-

Here is my latest update. I swapped radiator vents putting the fasted vent on the cold radiator and the adjustable on the ones that were getting plenty hot.

With a cold start - I could definitely hear more air coming out of the cold radiator for a longer period of time. When the other four radiators became hot this escape of air seemed to stop with still no heat at all.

At that point I checked the pitch. From the outer wall in the basement to the first elbow back to the boiler (8 feet ish) theres at least a 6 inch pitch. After the elbow a 5 feet length with a healthy pitch, but not as a aggressive. I used a laser and there are no dips or sags unless something is hidden in the wall as it goes to the 3rd floor.

In addition to checking the pitch, I raised the cold radiator +3/4" on top of the already 1/4" lift and re pitched.

Nada!

Again, when I turn off the system, you can hear the steam rushing up to the cold radiator, which lasts for about 20-30 seconds. With my hand on it I can even feel it rushing though the pipes.

Time to call in the big guns it seems to address the ideas above... I'm all out of do it your self ideas.

acwagner

I'm looking at your photos again. I noticed that your living room radiator take off looks kind of low on the system. Is that the boiler in the background? Can you measure from the floor to that take off and the height of the waterline from the floor? It's possible water is getting into your dry return and causing all the breathing and preventing the radiator from heating.

matthewb84

@acwagner I will be able to measure later today but here is the picture of the system. You can see the LR take off and the boiler to the right. What you see in the above picture is a water heater.

Fred

@matthewb84 , I see the large main and two smaller pipes, one on the side of the riser to the large main and one about midway in the Main, before it turns but I only see one wet return. Where do those two smaller pipes drain? That long pipe over to the riser seems pretty level too. Seems like there should be a little pitch, away from the riser out of the boiler and a drip leg that drops into the wet return so that condensate doesn't have to run back down the boiler riser.
Also, is the header, above the boiler at least 24" above the boiler water line?

acwagner

Ok. I thought that take off was at the end of the system. I see now it's the first one. So that first part of the system is counterflow, as in the steam goes in one direction and water goes back to the boiler in the opposite direction. Can you take a picture of the boiler rating plate? You may have to remove the front cover on the boiler to see it.

Also does the pipe get larger in that vertical section from that long horizontal piece coming from the boiler? Hard to tell but it looks like it is 2.5" at that vertical section.

I'm thinking the problem lies in that long horizontal piece. You could be getting water in there because of a number of reasons and the steam and water are fighting it out making the breathing noises. Still trying to figure out why that radiator won't heat at all. Does that pipe run out get hot? Does the valve? Or is the whole thing cold?

mikeg2015

Kahooli said:

I'd turn one of the bedroom vents upside down and see if the Living room radiator heats.

Also, not having a room heated properly should be grounds for getting your lease terminated depending on your municipality. Talk to your landlord, if they refuse to have the PROBLEM fixed, then look at your options.

Check your state or city, but normally you have to keep paying rent, notify them by certified mail of the issue. Get a thermometer and take a picture of it. Document every conversation you have in person or phone.

There may be an option as some point to withhold rent but put it in an escrow account, and mail them a copy of the statement.

Just some ideas, but you may need to lawyer up early on.