All pipework replaced - still little to no heating downstairs

[knightime]

Hi,

Yesterday we had all the pipework for our central heating replaced, as we were having an issue with the rads downstairs not working (after a recent rad replacement and power flush).

When the guys left yesterday all the rads were working - we had full heat in all rads - boiling hot! We had the central heating on till around 10.30pm before shutting the system off.

However this morning, when the central came on, only the hallway rad was on, and it was barely hot. The rads for the dining room and the lounge were stone cold.

I dialed back the lockshields for the rads upstairs, as they were left fully on, and am confident they're nicely balanced as there's good heat coming out of them. The flow pipes into the rads upstairs are roasting hot.

The flow to the rad in the hallway is hot, not roasting, but hot. I've checked the pins on the TRVs on the two rads in the other rooms and they're pushing down/popping up ok i.e. not stuck. The lockshields on the rads downstairs are also fully open.

I checked the main flow pipe from the boiler to the heating downstairs - the pipe is boiling hot. But the return is cool to touch - not stone cold but not warm either.

I'm trying to get hold of the plumber but he's not answering, so will try again later.

In the meantime does anyone have any suggestions as to why, with new pipework, and with the rads working fine yesterday, they've suddenly stopped?

Any advice would be greatly appreciated!

 

[Best]

If your original pipe work was badly installed, soldered etc, or simply undersized, then it is good to have it all replaced. But an embarrassing mistake if pipe work was okay and pump is faulty.
Classic sign of a part working faulty pump is as you describe - heat not going to the furthest rads, particularly on drops, but flow pipe sometimes getting hot.

 

[knightime]

I really appreciate all the advice received so far.

From everything I've read, and from what you've said, it appears the pump is the issue - I didn't realise you could still have heating upstairs even if the pump wasn't working! Is there a way to visually check (listen to?) to see if the pump is working properly, or does a pro need to look at it?

 

[Best]

Usually just I replace the pump if everything else seems ok.
Faulty pumps can be spotless inside and appear to be pumping strongly but are the problem.
A weak pump or a pump with blocked impeller will take the easiest circuit.

 

[knightime]

Here is the pump in question...

 

[jonnyswamp]

You say he used plastic pipe as a replacement, what size are the feeds to your rads?
If 10mm are they fed from manifolds?

 

[knightime]

Give me a mo jonny and I'll check...

 

[knightime]

Jonny, they're 10mm fed pipes with 'T's going off to the rads, but not manifolds...

 

[Tonycane]

Was the existing pipeWork plastic or copper?

 

[knightime]

It was all copper Tony - basically the pipes that run from the boiler and under the bath were cut just in from of the sink and replaced with plastic. The only new pipes the replaced made of copper are the flow/return pipes going from the landing upstairs and down into the kitchen. They used both 22mm and 10mm plastic to replace all the other old copper. The more I read the more I believe it's nothing to do with pipework but with the pump itself - perhaps when they originally took it off to flush through the system it wasn't put back on properly, or it was faulty to begin with. Either way everyone is saying that for heat upstairs/no heat downstairs (which is such a common issue), the pump should have been the first thing to check.

 

[knightime]

Sorry - typing on phone - hope that made sense!

 

[Tonycane]

Get the pump changed to rule it out.

 

[SimonG]

Jonny, they're 10mm fed pipes with 'T's going off to the rads, but not manifolds...

There's tees on 10mm pipe?

 

[SmokeyJ]

Hi knight just read your thread. I had a similar issue with a Potterton Performa 24 boiler. All rads downstairs but 1 cold upstairs were ok, it turned out to be a clogged filter in the boiler return valve. I'm sure your boiler still uses the same return valve as the Performa. If so there is a gauze filter inside the return valve under the boiler. It is inside the valve body behind the blanking cap/filling loop connection and sure it is not mentioned in the manual. It would be worth getting another engineer in for a second opinion and check if the filter is blocked.

 

[knightime]

@simon - yep, 22mm main feed, T off to 10mm to the rads.

 

[SimonG]

But they didn't tee off 10mm to other rads?

 

[knightime]

@smokey - my wife and I were just having that discussion - yes, we're going to cancel him tomorrow and start looking for another plumber for that 2nd opinion - whoever we get I'll pass on you message re the filter!

 

[knightime]

Simon - I now wish I'd taken pictures when the boards were up. The main feeds from/to the boiler were all 22mm. Where they then T off to the rads they used 10mm pipes, and they T off, also 10mm, to all rads.

 

[SimonG]

So just to confirm that there is 10mm pipe that has been teed into to feed other rads?

 

[knightime]

UPDATE: the plumber came round, he checked the pump which he said was working fine. His opinion is we need a new boiler (ours is only 4 years old!). So we're now looking to get second/ third opinions, but any more advice is extremely appreciated!

SimonG sorry for not replying to your last post sooner. There is one 10mm pipe that has been teed into to feed another rad from one upstairs bedroom to another - they copied the flow of the old pipework when they replaced it with the new pipework.

 

[Best]

How did he check the pump? I have never been able to say for certain a pump that appears otherwise in perfect working condition is faulty or not, without replacing it.

 

[Riley]

UPDATE: the plumber came round, he checked the pump which he said was working fine. His opinion is we need a new boiler (ours is only 4 years old!). So we're now looking to get second/ third opinions, but any more advice is extremely appreciated!

SimonG sorry for not replying to your last post sooner. There is one 10mm pipe that has been teed into to feed another rad from one upstairs bedroom to another - they copied the flow of the old pipework when they replaced it with the new pipework.

What is his reasoning for new boiler??? On one hand he says the pumps fine and on the other the boilers shot??

 

[SimonG]

Shouldnt tee off 10mm its too small and cant carry enough heat. If its plastic as well it will be even more restricted.

 

[SmokeyJ]

Cowboy comes to mind.
Did he check for the return filter??

 

[jtsplumbing]

Do the pump & filter B4 anything else, simple to do on your boiler, Then if that fails to solve the problem ! its time to look at pipe-work

 

[knightime]

Just a quick update - we've got a different plumber coming to us on Thursday, but in the meantime the rad in our bedroom is now not receiving any heat, and the rads upstairs are barely warm - it's now 9.36pm and the central heating has been on since 4.30pm! I'll pass on the message re the pump and filter and will update. @Riley - yep, we thought the same thing! There's clearly no flow at all, although the boiler is putting out hot water (the flow pipe to downstairs is scalding hot!) I need to keep documenting this for anyone in the future who experiences the same issues. Really appreciate all the advice given to us so far!