hot water won't enter radiator

BobR

I have a gravity fed system. Just recently did a bathroom renovation. Had the radiator removed and sandblasted and reset. Now hot water won't go into the system. I've bled air from the radiator and water does come out of the valve. The original floor was removed and replaced we new sub floor, concrete and tile so it's about 3/4 to 1" higher than before. The heating guy did pull the radiator to look for debris from sand blasting and inspected the valve and and it is open and functioning. I'm not sure what the next step should be. Would the floor level change impact a closed hot water system? Thanks.

EBEBRATT-Ed

Lowering the radiator could cause a problem. I wouldn't think raising it would. I would suspect it is still air bound. You only mentioned 1 pipe. Is this hot water or steam??

JStar

Can you post a picture of the radiator and any piping that was changed?

BobR

Ebebratt-Ed: This is a hot water system. One pipe in, one out.

JStarr: Here is a picture after the reinstall

JStar

Was the supply pipe ever connected on top of the radiator? Is this exactly how it looked before? Has anything else changed in any other parts of the system?

JStar

Also, was anything accidentally stuck in the return pipe? When you bled it, did the water get hot? Did the hot water come from the supply or return? To test if the return is clogged, you can close the supply valve and bleed the radiator again. If hot/warm water comes out, the return is open.

Fred

Did they stick a rag in each end of that radiator when they sandblasted? More important question is did they take any rags out when they were finished?

Gordy

Not only rags in the rad, but what about the open pipes during the period of renovation until the rad was set. Also looks like some return piping was replaced.

Paul48

When he pulled the radiator, did he check the valve to make sure it was working correctly?

BobR

these are all great responses and I appreciate it. Let me answer:

Paul 48, we did pull the radiator and the valve was working according to the heat guy.

Gordy; the pipes were capped at the time the radiator was pulled. Very good eyesight, the return pipe was replaced with a longer pipe since the floor was raised about an inch.

Fred: I'm not sure if they put rags in the radiator when they sandblasted it. When it was returned I didn't see anything sticking out of the holes.

JStarr: this is how the pipes looked before, but I would say that it seemed to pinch toward the supply valve not the return. I never put a level on the radiator before we pulled it but from memory and a picture to support my thought it tilted toward the source. Seems odd that it would work that way. Subsequent to the picture I shared, the heat guy returned and pulled the radiator, checked for obstructions and tested the supply valve then when he reconnected, he placed 3/8 " tile under the legs on the bleeder valve side thinking that it would help air rise to the bleeder valve. When I open the bleeder valve water does come out but it's cool, not warm. If you bleed it long enough, the water does warm a bit but not like it did before. No parts have been changed.

Thanks again for the comments.

nicholas bonham-carter

If you bleed the radiator, and it becomes warm, then wouldn't that point to an airlock, or obstruction in the return?
This case is similar to another one here on the wall, a while ago, but I can't find it. It may have involved using dish soap, to dissolve the air into the water in a difficult to purge line. Would anyone else remember?--NBC

Marz

Maybe one side needs to be isolated in order for the air to come out. Is there a shutoff somewhere on the return in the basement?

BobR

Not that I've seen.

Gordy

This should not be that big of a hassle. Are you absolutely positive there is not another isolation valve else,where that is still closed?

j a_2

I agree ....something has been overlooked.. If it did work prior then it should definitely work now...

BobR

Gordy: I'm positive, absolutely, there is not additional valve. I've followed the pipes in the basement to where they rise to the bathroom on the second floor. Nothing but the radiator and the return pipe were touched. As I indicated earlier, the new floor is higher than before and so the return pipe was changed. The bleeder valve side of the radiator was raised slightly higher than the supply side where I think it was lower prior to the removal
of the radiator. I'm not sure that makes a difference or not. The heating guy says it could cause an air lock when the bleeder valve is lower since the air won't rise to that spot. I'm starting to think that it is the supply valve. The hot water stops at the valve. Even though the heat guy could see that the valve is working the heat stops right there. I"m getting water from the bleeder valve.

Marz

The water coming out of the bleeder is probably coming up from the return pipe rather than the supply pipe.

JUGHNE

This is still a gravity system with no pump? What pressure or height is showing on the gauge at the boiler. And do you run the same water temp as previous?

Paul48

OK.......Re-pitching a cast-iron radiator to "get air out" is silly. If the radiator was half full of air, it would still function in a gravity system. Only half the radiator (bottom half) would get hot. I still think the valve is closed. The handle turning does not mean anything. It may be broken closed.

JUGHNE

Did you take the valve apart. If you remove the bonnet/stem/handle assembly you should be able to see straight down the riser pipe. The rubber washer or the disk holding it may be broke off and plugging the valve seat. It would appear to be opening when viewing from the side port but the rubber washer could be permanently seated. Without a pump not much pressure available to push.

j a_2

Yes why even would you use a valve unless you used 2 of them...even then why.? Original ones some used restricter offices..Back to the basics in this one

JStar

My guess is also that the inside stopper in the valve broke off and is laying on top of the pipe opening. Drain the system, open the valve from the top and check it out.

BobR

this is all great advice and I appreciate the input. I'll get back with the technician, or a different one, and discuss looking at the valve. I think that is the best approach. Interesting that the pitch of the heater has no relevance to water circulating. (Thanks Paul48) Thanks so much for everyone's input. I'll report back what we find. Not sure when I can get this completed, and with warm weather now here, not sure if this is the time to turn on the furnace.

JUGHNE; pressure gauge is at 10, no pump pure gravity feed. Ran it at the same temp. No we did not disassemble the valve.

RobG

Can you post some photos of the system? Boiler and radiator.

j a_2

Wondering if I missed a post of the pictures....

nicholas bonham-carter

BrooM, why don't you take out an advert on the site here, and you wouldn't have to read all these posts, and post a "Verano" reply!--NBC

BobR

If you're still listening, I did find a contractor who did a great job at diagnosing the problem and fixing it. It turned out that the plug used to cover the water intake for sand blasting the unit was stuck inside the radiator. The technician pulled it out, added a new valve and hooked it back up to the system and it works like a charm. All your help and insight have been invaluable. Thanks for responding! All the best, and my apologies for taking so long to report back to you.

leonz

Glad to hear that the problem was found and fixed and a new valve was installed to replace the old one.

If you run in to air problems again while bleeding air squirt a tiny amount of dawn in the open to air tank if it has a hot water return loop back to the boiler or if you have to drain the boiler down to change or clean the Low Water Cut Off if it is a wet contact conductive LWCO.

delta T

Btw, if you have pictures of the boiler we would all love to see! Its rare to see a gravity system still in operation, we all love nerding out over this stuff....

Glad its working for you!