Some radiators not getting hot after recent work

[Jack Cruwys-finnigan]

Hi, I have got some trouble with my heating system.

We recently had our very old heating manifold replaced by our plumber. One of the ports had sheared due to corrosion over the years. See attached pic of manifold. Our plumber was not able to source the same part, as they are not made anymore and has instead used a series of Hep20 4-port manifolds to create something similar to what had been cut out.

Since this procedure, we have had many issues with our hot water and heating. After a lot of tinkering the plumber was able to get the hot water back on - he thinks this was due to air in the system - and this now works perfectly. The heating however is still not working that well. He has told me that he has worked many more hours on this job that he expected to and that any further work will have to be quoted for – I understand this and is completely fair. Therefore I am trying some solutions myself.

We have 7 radiators and only 2 of them get really hot, 2 of them get a little hot and 3 don't get hot at all. He says there is air in the system that will gradually need to clear over time as we run the heating, hopefully working its way into rads to be bled off.

Nothing has changed over the last week or running the heating and hoping for change. Yesterday, I used a hose attached to the bleed valve to blast water (and hopefully air) from the radiators/pipes leading to said radiators out of the hose to clear any air locks under the floorboards. I was able to draw hot water to all the rads that weren't receiving hot in the past - I also heard quite a bit of air pass through the hose too. I was very happy with myself at this point. This lasted for about as long as it took me to put the bleed valves back on and turn the heating back on and see that the problem still persisted. The only improvement being is that hot water now reaches the flow valve of the rad, but seems to refuse to enter and flow through.

I have tried shutting the lock shields on all other rads to divert heat solely to the colds rads with no avail.

Is there anything else I can try before I have to start forking out for the plumber to come and troubleshoot/replace things again?

Some things to note:
• I have a one pipe system (according to my plumber)
• My heating is not pressurised
• I live in a bungalow and therefore do not have loads of drop to force water round the system
• My pump is on its highest setting (3/3)
• My heating has been plumbed in 10mm microbore
• Everything was working fine before this manifold was replaced – all rads used to get as hot as they needed to.

Thanks in advace

Jack

 

[motorbiking]

Its possible that your radiators are not all on a flow and return loop and that some be in series?

 

[Exedon]

If your plumber thinks a 10 mm manifold system is one pipe it's time for a different plumber!
Assuming all the rads worked before it should work again .
Picture of new manifold would be good.

 

[Jack Cruwys-finnigan]

I’ll take a pic when I get home. Had a new plumber round today for a look at it and he’s not sure it was done correctly. Will be phoning the original plumber tonight and asking him to come back round and check his working.

The new ‘manifold’ is now just a collection of 22mm 4 port valves in a row. I have to say it’s not amazingly tidy work and wasn’t supported at all, which I have amended myself as it’s very heavy and was just dangling.

 

[Harry Bloomfield]

Aside from the above problems, and assuming an air lock - try turning all of the radiators off, but turning one on at a time, to force air out to each radiator in turn, combined with bleeding.

 

[Jack Cruwys-finnigan]

Thanks for your suggestions everyone - it turned out that the replacement had been carried out incorrectly.

The original manifold was split into two chambers internally, thus creating a separate flow and return. The plumber had just replaced it with a run of ports with no set flow or return, so it was a miracle heat was getting to any of the rads.

It's now been sorted... by another plumber.

Attached are pics of the original work. All it took was to switch some of the pipes round and create a block between the F & R.

 

[Exedon]

I did indicate originally plumber didn't quite hack it lol.
Pleased you have it sorted .

 

[conny]

Well done to the plumber who figured out what was what with that lot!

 

[Harry Bloomfield]

Well done to the plumber who figured out what was what with that lot!

Checking things out via measuring resistance might have provided clues - no conductivity through those plastic fittings.

 

[Exedon]

Dead easy to trace a manifold system.
It's all in pairs blow down one pipe and you have found other end!.

 

[Jack Cruwys-finnigan]

Great tip!