radiator not working

CapeCod

I'm sure this question has already been asked a 1000 times but I have a radiator not working and I need to get it fixed before I sell my house. Can't find anyone to come out and take a look at the moment because everyone is busy with AC work I guess. I've had air locked radiators in the past and usually have been able to fix it but this one just is not working. I have a continuous operating system with home run piping to each radiator in the house. Things I've tried so far:
1) Bleed out the radiator
2) Shut off supply and return to all the other radiators and bleed out radiator in question
3) swapped TRV on radiator with a known good one

Nothings is able to kick start the flow again for some reason. The radiator is on the first floor, close to the boiler in the basement. All other radiators in basement, 1st floor and second floor are fine. Any other ideas please? thank you!

EdTheHeaterMan

There is a blockage. If you have individual isolation valves on each supply & return pipe to that radiator, you can remove the pipe and test the lines. If not isolation valves then you need to drop the pressure and remove the suspect pipes from the system and add valves to test those pipes for a blockage.

CapeCod

Thanks - I was hoping there was one more easy thing I could try....might have to call a professional!

EBEBRATT-Ed

@CapeCod
When you bleed it do you get air or water? If you get air it's air bound. If you get water it's not an air issue, it's a flow issue.

Try shutting the return to the rad and bleed it with the supply open. Then shut the supply and open the return and do the same thing. Open both valves when done

pedmec

why type of heating system piping plan is it. maybe take pic of piping with good view. would help maybe identify whats going on instead of guessing at it.

CapeCod

CapeCod

Thanks again for the replies so far. Hopefully these pictures give a better idea of what is going on. There is a separate branch that runs to 3 different radiators that were added after the original install. That branch has a manifold where I can shut off each of the 3 individual radiators separately and a drain valve at the end of the manifolds (both supply and return). I believe I did as Ed suggested.....shut off the return completely and drained out the supply side. Then I shut off the supply and drained out the return side. I got some black water at first but that's about the only weird thing I noticed. It seemed to drain pretty well and I didn't hear any hissing of air. I just drained til the water stopped. Now it is heating up and I guess I'll see if any heat comes through?

EdTheHeaterMan

In order to PURGE the pipe and radiator of the problem section of pipe, you can place a pressure hose on the boiler drain located on the return. A washing machine hose with two female ends will get you there. With all service valves closed turn on the pressure and charge the return. As long as there is no place for that water to go because all branches and the yellow handle on the return branch ball valve are closed, there will be pressure and NO outlet. there will be no flow. I'm trying to be as clear as possible.

Next open the valve to the problem radiator. Now you will have pressure in the loop with the radiator. The radiator will have pressure in it, and once filled with pressure there will be no movement.

With the radiator pressurized, you can now open the supply side of the loop in question. as long as all the supply side valves are closed you will then have pressure on the supply side and have no water movement.

With ONLY this circuit pressurized with water, when you open the boiler drain to the supply end of the system on the end of the manifold you will get a PURGE of water and air pressure and all the blockage will be forced out of the system.

You will want to put a bucket under that supply side boiler drain to catch all that blavk water that will be coming out.

I think I might have the answer to why there might be a blockage

Does that PEX tubing have oxygen an oxygen barrier? If not then you are getting oxygen migration thru the tubing that is working on any ferrous metal in the system. That is causing oxygen to act on the metal and basically rust away. This rust is forming black and or red mud to develop in the system. A typical circulator pump can not move heated water thru the mud. You see, the water will take the path of least resistance. as the mud accumulates in the pipe, there is more resistance to flow. That allows more mud to build up which increases resistance to flow, that allows more mud to accumulate, that reduces flow that allows more mud to build up... You see where this is going. Eventually there is so much mud that you need to PURGE that pipe with high enough pressure that the blockage will be FORCED out of the pipe.

The correct fix to this problem is to replace all the PEX that is not "o2 barrier" with PEX that is "o2 barrier". I know this is not great news. But you may have recourse if you can get in touch with the original installer of that PEX pipe and require them to install the correct product.

EdTheHeaterMan

Here is a rough diagram of your system of only the parts needed to illustrate the PURGE

By closing all the valves except for the 2 needed to force water thru the problem loop and 2 boiler drain valves, the high pressure water has only one place to go. (illustrated by the blue dotted line). The pressure of only gravity on the blockage that is exerted by just draining the radiator may not be sufficient to clear the blockage.

Larry Weingarten

Hi, Here's a close up of the Roth tubing. It looks like it has the EVOH barrier, so hopefully non-barrier tubing isn't the problem. It would be interesting to see what comes out of the system on flushing!

Yours, Larry

EdTheHeaterMan

@Larry Weingarten I was looking at that tubing and I can't see the complete info. and I'm not familiar with Roth. Is that the semi opaque translucent tube with gray water coloring inside like Wirsbo HePEX or is that grey the color of the tubing like the old Quest water pipe. That brown line on the opposite side of the tubing might help Identify

I hope you are correct for @CapeCod's sake

Larry Weingarten

Hi @EdTheHeaterMan , I had to put together info from a couple of sites as Roth wasn't being very clear on what their five layer tubing is, but the duoPEX S5 looks very hopeful. I'd like to see more of the marking on the tube just to be sure also! I'm trying not to be un-cautiously optimistic.

Yours, Larry

CapeCod

Thanks again for taking the time to post your thoughts...very much appreciated! I hope to have some time this afternoon to read through everything carefully and follow up. I have a utility sink about 25 feet away so I can supply water from there with just a garden hose hooked up to the return side to flush?

I will try to get some more details on that pex to hopefully rule out the O2 issue.

EdTheHeaterMan

CapeCod said:

Thanks again for taking the time to post your thoughts...very much appreciated! I hope to have some time this afternoon to read through everything carefully and follow up. I have a utility sink about 25 feet away so I can supply water from there with just a garden hose hooked up to the return side to flush?

I will try to get some more details on that pex to hopefully rule out the O2 issue.

I like to push blockages back to the source and out the other end. That is why I chose to pressurize the return. If there is a blockage that does not blow out, (nothing comes out the other open drain valve) you can try pressurizing from the supply side (in reverse) to see if that helps remove any blockage.

CapeCod

Well - good news / bad news so far. I checked the pex and there is an integrated O2 barrier but unfortunately I still can't get the flow
going after pressurizing the return side. It wasn't exactly gushing out but there was a steady stream of water. A little greyish but not black like the first couple quarts that came out initially. I did try the reverse yesterday and pressurized the supply side. Water actually started coming out of the drain valve which seems to indicate the blockage is right at the supply valve to the radiator in question. Maybe a defective valve that is not fully opening? I'm going to start looking for more phone numbers of people to call to have a look as I'm running out of time before closing on the house. I'm really curious to see what the problem is here......

EdTheHeaterMan

I'm wondering what type radiator you have. Is it a radiator that has a union fitting on both sides? If it does, Then you can loosen the unions and remove the radiator to see if there is an orifice in either the valve side or the union only side. Those orifice plates were there when the old gravity flow piping system was used. If the home was repiped from that type of old system, and the orifice plate was not removed, then that may be the restriction.

That orifice plate may be removed completely to get your radiator to heat.

CapeCod

I've actually got Myson panel radiators so I'm not sure that would be the case. Finally found someone to come out Friday so hopefully the mystery will be solved then! Will let you know!

EdTheHeaterMan

Myson Panel rad may have a built in valve. It is there if you wish to use a TRV actuator. (Thermostatic Radiator Valve) If you do not use the TRV actuator then the factory supplied manual cap will be able to fully open the valve. If that cap is lost or missing, then that radiator valve is probably closed.

See the red cap on the right. That will depress the valve to the open position. (if that is the model radiator you have)

CapeCod

Hello Ed - Just closing the loop on this one as I finally got it to work. It turns out the valve body to the TRV had seized or something and that was blocking the flow. I was able to order a new one and installed it myself. I've learned a lot dealing with this system in the 10 years I've had it....now I'm selling my house so I think I'm going to miss it.