3 Radiators Not Working

[Chris Orrick]

Hello all,

I'm hoping someone out there may be able to help as I'm gong around the bend trying to understand why only 3 radiators won't heat up!

My story: Around September 2021, 2 of the 3 radiators were not working and since the cold weather was coming and since the boiler usually gets it's annual service around Sept / Oct, we asked a local chap to come and have a look. He suggested that a power flush would be his first call - which he did. The problem still existed after the power flush.

He did also say that my youngest son's radiator was turned off (I think he must be a polar bear as it hasn't been on in quite a while) and that this may be causing a blockage.

He drained the system and then put various cleaning chemicals into the system to try and dislodge any 'gunk' that may be in there - this didn't work either.

Ultimately he says that he may have to lift the flooring to replace the pipes as he feels the pressure may not be right or there is a blockage.

I'm really not too keen on lifting floors, so I changed the 3 radiators myself for new ones (just to see - and because they look better anyway) and when I opened both the TRV and lockshield, water flew into the radiators - so wondered if that means that there isn't a blockage?

All 3 of the radiators still wont heat up - none of the pipes on either side are hot, or even warm?

I'm just a diy'er and not that experienced around rads and heating, but happy to try and learn.

Thank you for your comments in advance

Chris

 

[Deleted member 120897]

Hi Chris,

has the system been balanced at all? This would have been my 1st port of call, before any flushing. If water entered the radiators, it would suggest no blockage. Any reason in the first place why they didn’t heat up? Did they previously? Have the TRV pins been checked for sticking?

 

[Chris Orrick]

Hi Chris,

has the system been balanced at all? This would have been my 1st port of call, before any flushing. If water entered the radiators, it would suggest no blockage. Any reason in the first place why they didn’t heat up? Did they previously? Have the TRV pins been checked for sticking?

Thank you for your response - I believe that the system was balanced - but could not swear on it.

The radiators did previously work and I cannot recall of any particular reason why they wouldn't work, although my wife seems to think that they stopped working after I removed the bathroom towel rad for decorating (but this could just be complete co-incidence?)

I've never checked the TRV pins - will get on to Google to check out how to do this, but find it strange that 3 pins would get stuck at the same time?

Sorry I should have mentioned that the radiators that are not working are the original ones and that we have had probably 5 additional radiators installed over the years around the house.

Do you feel there is anything in the chap saying that there could be pressure issues meaning that the radiators are not getting hot? He seemed to suggest that there might well be a 'junction box' under the floor somewhere which may not be pushing sufficient water through for the radiator to get hot?

Can completely understand how people can get sooooooo frustrated with this stuff.

Thanks again, kind regards - Chris

 

[SJB060685]

Have these three radiators ever worked?

 

[Chris Orrick]

Have these three radiators ever worked?

Thanks for your response - yes they have all worked previously.

 

[cjg]

is it an one pipe system ? had new rads fitted wrong ?

 

[SJB060685]

Have you ever experienced problems with air getting into the system? If these radiators once worked it’s not a balancing problem (unless someone has fiddled about). The pump could also be struggling. Are these radiators furthest from the boiler?

 

[ShaunCorbs]

Have you tried turning all but the faulty ones off to see if they heat up ?

 

[cactus]

Have you tried turning all but the faulty ones off to see if they heat up ?

Not to hijack but I've a similar issue that I'm unable to post my own thread about.

What happens if they do heat up in this scenario?

 

[John.g]

Possibly pump head (pressure) too low. If still no flow, leave only one rad opened up, if flow established, shut this rad off and go to next one until all OK. If you have a external pump post a close up view of it. If you have a sealed system ensure boiler pressure not < 1bar when cold, if open vented ensure small (feed & expansion) tank in attic "full" of water.

 

[cactus]

Possibly pump head (pressure) too low. If still no flow, leave only one rad opened up, if flow established, shut this rad off and go to next one until all OK. If you have a external pump post a close up view of it. If you have a sealed system ensure boiler pressure not < 1bar when cold, if open vented ensure small (feed & expansion) tank in attic "full" of water.

I am getting flow in most rads, two upstairs rads on one leg heat up nearly just fine, there are 3 downstairs that barely get warm and the other upstairs ones are pretty warm if all the others shut off, but barely warm if they're all open. I feel that perhaps I've got a block in a pipe, judging what's been going on. I can feel BIG cold spots in the downstairs rads, so I'm going to pull them off, blast them through with water to remove the sludge, chuck in some x400/x800 (Whatever is best) and then run the system to see if that improves, if not, I was planning on hiring a Norstrom proflush to flush the system.

 

[John.g]

Just prior to removing the rads you might consider (with boiler shut down) shutting off the valves on one of the downstairs rads, remove the vent complete or if installed, the plug at the other end, open one isol valve fully and let the water flow into a container for say exactly 10 secs (but no longer than 30 secs) and measure this amount, shut off this valve and repeat with the other valve open and compare measurements, before commencing each test, top up boiler pressure to exactly 2 bar, this test may show if the problem is either a blocked flow or a blocked return, but not guaranteed if the bottom of the rad is full of sludge. If a open vented system test time can be 30 secs or so.

 

[cactus]

Just prior to removing the rads you might consider (with boiler shut down) shutting off the valves on one of the downstairs rads, remove the vent complete or if installed, the plug at the other end, open one isol valve fully and let the water flow into a container for say exactly 10 secs (but no longer than 30 secs) and measure this amount, shut off this valve and repeat with the other valve open and compare measurements, before commencing each test, top up boiler pressure to exactly 2 bar, this test may show if the problem is either a blocked flow or a blocked return, but not guaranteed if the bottom of the rad is full of sludge. If a open vented system test time can be 30 secs or so.

I want to say it's the flow. I followed a plumber parts video to remove an airlock. It gurgled and BLACK water came out. I also felt some warmth, but after re-pressurizing the system and opening the lockshield, the rad went cool quite quick, which makes me think the flow is at fault. The hall rad is getting hot to the touch, its now just the dining room, which is getting slightly warm, but just barley, and the near cold living room. I've put in some x400 as I'm going away tomorrow, so I'll see how or if that helps remove anything, who knows.