cold radiator cold feed

richarddowling

Replaced valve and trap. Disconnected radiator that once heated OK and hear gurgling sound in return line. First time I fired up boiler in early winter, whole radiator heated. has not worked since. All traps on same feed line working OK.

Fred

Is there proper pitch on the radiator and return line from that radiator? Sounds like water sitting in it.

aircooled81

Why did you replace the valve and trap?
What did you meen by 'disconected radiator'?
Did you replace the trap because it (radiator) was not heating, or routine maintenance? Any chance you could open the trap or remove it to blow down the return line, and see if thats clear?

richarddowling

Checked pitch to drain as is Ok. Also blew air through radiator. hardly any water drained out. I replaced valve and trap as routine maintenance since I believe 3 they were original and previous owner had not. I was blowing steam into the return since trap failed open. I just removed radiator from valve and return line connection to drain any possible water. I have not tried to blow down air down return line. Will do that next. Is there any way to vent water from return line or isn't that recommended? i.e. tap in a small removable plug?

Jamie Hall

If water isn't draining freely from the return line, it is either pitched incorrectly (moderately likely) or plugged (highly unlikely). The former would normally show up as poor heat in the radiator -- since in two pipe systems the return is also the only way for air to get out -- and might sometimes show up as a water hammer.

There should be no need to vent water from a return. It's got to get back to the boiler, after all.

JUGHNE

With that rad valve off and the top of the trap open with the element removed, then if the steam is up then nothing should come out of the trap body, right? Providing all other traps close on steam.

So if you see no steam there then you could carefully open the rad valve to see if air was venting out the trap and eventually steam shows up.

Be careful and have someone close to the T-stat or boiler switch.

richarddowling

Pitch is good. I have steam in feed pipe in basement and both radiators on 2nd floor. Is this steam condensating down below in feed pipe and they are full of water? if so, can I tap the pipe to drain it and add a plug or small valve? I do get some hammering in feed pipe when boiler is on. Only using 1psi of feed.

Jamie Hall

Pitch is good? Are you really sure? If the pitch is good, draining won't do a bit of good. It will drain all by itself. If it's hammering -- even a little -- the pitch isn't good. Water is accumulating somewhere, and until you find it and correct the problem permanently (I'm sorry, but your drain idea will work for exactly one boiler cycle) you won't have progressed.

richarddowling

Pitch on radiator is good. I'll need to check pitch on condensate lines more carefully. But is steam feed line pitch also an issue? When it cools, is condensate supposed to go back to boiler?

vaporvac

Yes, condensate is meant to return to boiler.

richarddowling

So I disconnected cold radiator. Blew about 20 psig of air into it and it flowed out condensate opening no problem. Decided to blow air down steam feed and did this for about 20 seconds while boiler was running and then after 5 seconds, I heard steam pressure building in feed and then had steam visually flowing out of radiator inlet feed valve. I believe I have a water pocket in feed line. I don't get hammering though(?) I can see a wrong pitch in basement, but it is in a spot that is way up in corner of crawl space where it feeds into wall. Not sure what I can do. Can't be much water, but enough to block 1.5 psig of steam on feed. Any suggestions?

Fred

If the supply pipe pitched the wrong way where it turns and ties into the riser, it doesn't take much water to completely close off that elbow, blocking steam from getting through. The only real solution is to correct that pitch. It may be in an inconvenient spot but it still needs to be corrected.
With the radiator disconnected, can you pull that riser up, from the floor easily? If so, is it enough to correct the pitch in the basement? If it does, you can put the radiator up on small blocks to allow you to pull the pipe up and connect it at that higher level.

richarddowling

I'll try to raise the pipe from above and put the radiator on blocks. Not sure how much "give" the pipes have, since i'll have to raise drain line also. (2 pipe system) Thanks Fred.

Fred

richarddowling said:

I'll try to raise the pipe from above and put the radiator on blocks. Not sure how much "give" the pipes have, since i'll have to raise drain line also. (2 pipe system) Thanks Fred.

Shoot. That certainly makes the situation more difficult.

EBEBRATT-Ed

What @Fred said to do is correct if you can do it. Try raising the radiator on both ends but maintain a slight pitch toward the return, you don't need too much pitch with a two pipe system. Even raising the radiator 1/4 inch or more can help the problem.

You could also shut the boiler off remove the radiator trap cover and pour water into the trap and see if it drains freely.

richarddowling

Was able to raise the radiator pipes about a 1/2 inch, put radiator on blocks and I am getting steam into radiator now!! Thanks Fred!!

Fred

richarddowling said:

Was able to raise the radiator pipes about a 1/2 inch, put radiator on blocks and I am getting steam into radiator now!! Thanks Fred!!

That's great News!