All pipework replaced - still little to no heating downstairs

[Stu Davis]

Sounds like a circulation problem and i would have thought an air lock would be the problem.
I would check the pipework to the boiler and see of the flow is red hot and the return cool, if so definate circulation problem or blockage

 

[knightime]

*UPDATE* The central heating system has now failed - no heat in any if the rads...

 

[Tonycane]

This should make it easy for your next engineer to diagnose. Keep us posted

 

[knightime]

Hopefully Tony, and will definitely keep you posted!

 

[dave1]

I know its been said already but defo get the filter checked, I've normally found however that if that's blocked you get a bit of banging coming from the boiler. Good luck with it

 

[knightime]

Cheers Dave - I'll get the plumber to check the filter too. You know you normally get that central heating 'sound' when it's on (water flowing through pipes sound), well that isn't there anymore - will keep you all posted!

 

[knightime]

*UPDATE*

Ok, so a new plumber came in, replaced the pump and checked the filter on the return valve (which was clear of blockages).

Whilst it initially appeared that the new pump was working (and in fact it is working - it's firing away once it drops temperature, which it wasn't doing before), the rads upstairs and downstairs aren't working as they should be.

Let me clarify - the downstairs rads aren't heating up at all, even though the flow pipe from upstairs to downstairs is scalding hot! Non of the flow pipes to those rads have any heat in them. Upstairs, all the flow pipes to the rads are burning hot. However, whilst the batchroom radiator and the one in our bedroom are 'warmish' (thermostats and lockshields are fully open), the rads in both the boys rooms are cool to the touch i.e. little to no heat at all.

I've told my plumber that I'll be monitoring it over today and tomorrow, but to be honest, that fact that the downstairs rads are stone cold (they've all been bled and are full of water), clearly a new pump has only solved a part of the problem.

Incidentally, I checked the two 22mm copper pipes coming out of the boiler (flow/return) - one of them is scalding, the other is very hot. The return pipe from downstairs back to the boiler is cold.

If anyone has anything they'd like to add to this thread, something I can relay back to the plumber for him to investigate on his next visit, please let me know and I'll pass the message on to him.

Cheers!

 

[jonnyswamp]

Look for a manual bypass valve that maybe fully open
If there is one it should be near boiler/airing cupboard

 

[newcastle phill]

I still think there is a pjping issue. Is it or some parts an old 1 pipe converted into a 2 pipe system or setious air lock. How old is the system. Sorry havent looked through all posts as been busy ?

 

[Subby]

Rads need balancing if return pipe at boiler is very hot and some rads are cool

 

[knightime]

*UPDATE*

The plumber came round today and removed the Spirotrap MB3 that had been fitted to the return pipe as he wanted to elimintae it from the equation. Unfortunately it didn't work. He's ruled out any issues with the boiler and believes that there must be an issue with the pipework that was done.

His reasoning is that both the flow and return pipes connected to the boiler are both scalding hot - in particular the return, which is much hotter than the flow! He thinks there must be a piping 'loop' issue, and the flow is just returning without circulating. The only thing he can't get his head around (and neither can I), is why the central heating worked for one day.

He will be coming back on 8th April to begin pipework connection diagnosis. I'll be taking pictures and assisting him, and will continue to update this post.

Cheers!

 

[knightime]

**UPDATE**

So, 2 months now without central heating...

The plumber is coming around again tomorrow to take a look at the pipework, but I've noticed something weird that I want to know if anyone can help with...

So I took up the floorboards in the bathroom and identified the flow and return pipes the original plumbers cut into. These of course lead from the boiler to service the central heating.

This morning I turned the central heating on and left it to run for an hour. The flow and return pipes that are directly connected to the boiler were both scalding hot. I went upstairs and identified the flow pipe, which was also scalding hot. But the return pipe was cold!!! How is this possible? If, as the plumber suspects, there's some issue with the original pipework and the flow is leading straight back to the boiler via the return and isn't circulating properly, how can the return pipe directly attached to the boiler be hot, but the return pipe upstairs in the bathroom be cold???

When I spoke to him just now he seemed as baffled by this as I was. Can anyone shed any light as to what might be going on? Once again the boiler is a Potterton Main Combi 30 Eco. The plumber asked me to look in the manual for an automatic bypass section but I couldn't see anything in there about that. The boiler isn't making any strange noises when the central heating is on and the pump has already been changed.

Cheers!

 

[Tonycane]

I would be chopping the flow and return and make a loop, add one rad at the end of the loop just to verify circulation. I'm still thinking it's a pipework issue.

 

[knightime]

The plumber believes that the pipe with the green paint is the flow as the other pipe had a Spirotrap on (which he removed last visit).

Both pipes are scalding when the heating is on.

 

[Howsie]

Get someone else in, this long without heating is unacceptable.

 

[knightime]

Here's the main flow an return upstairs in the bathroom.

The lower pipe (furthest away from the sink) is the flow as it gets scalding hot within 3 minutes of the central heating being on. The pipe above it is the return, which remains cold during the test I mentioned in the previous post.

 

[knightime]

I have Howsie - this is the 2nd plumber I'm on!

 

[knightime]

Cheers Tony - i'll pass that on to the plumber tomorrow!

 

[Tonycane]

Can't see the pic, can you get to the pipe work directly above the boiler and show a pic?

 

[knightime]

Hiya Tony - the original plumbers couldn't access the pipework directly above the boiler as the bath is in the way - they had to cut the flow and return which came out from the boiler just in from of the sink, then used push connectors to join them to the new plastic pipework.

 

[newcastle phill]

Well if its a 2 pipe system i fail to see how it can be just returning without providing any heat to rads.
As I asked earlier...Is part an old 1 pipe system.
Sounds like the flow to upstairs is coming back into the flow somewhere else and not the return lol

 

[Tonycane]

I had an install with a similar problem, was 22mm speedfit on the first floor, the first 22mm speedfit tee off the flow blocked. Found the speedfit pipe insert had come loose and completely blocked the flow causing the same issues you have. I cut the flow and return and put a speed fit loop in connected to one rad to prove the boiler was doing good it's job and then passed it back to the installer. Just something to consider.

 

[knightime]

lol - you're probably right with the flow thing Tony! What I can't understand is why it worked for one day (the day the original plumbers left), but why the next day it failed!

I also don't understand how the flow and return pipes that I can see on the boiler are both hot, but in the bathroom only the flow is hot, while the return is cold!!!

It could have been that waaay back it was a 1 pipe system - the plumbers removed a lot of redundant pipework - but the 2 pipes above the boiler have been there since we moved in - 16 years now - so I'm assuming it's a 2 pipe system. All seems very strange to me...:ack2:

 

[knightime]

Thanks again for that Tony - I'll certainly pass on your experience to the plumber before he turns up tomorrow!

 

[Tonycane]

Flow and return being hot is the heat building up in the boiler and creeping up the return abit because it has nowhere to go.

 

[knightime]

Ahhhh, so it's possible for the flow to affect the return directly on the boiler side i.e both pipes hot, if the flow has nowhere to go?

 

[Tonycane]

Normally overheats first but it will get warm. I bet the boiler modulates down then goes off because it's sensing the return temprature

 

[knightime]

That's the thing Tony - it doesn't - and it doesn't make any noise/shut off/show error codes - it just chugs away like everything's fine! And that return pipe directly connected is as hot as the flow pipe, but that doesn't reflect on the flow/return upstairs. Sorry to keep repeating myself but it's proper confusing me at the mo lol!

 

[Tonycane]

Jesus, if I was local I would pop in just to see this ball ache!

 

[knightime]

Lmao - wish you were too buddy!!!

 

[knightime]

The answer is there somewhere - will keep you posted once it's all sorted (soon I bleedin' 'ope!)

 

[Howsie]

I have Howsie - this is the 2nd plumber I'm on!

Yikes! Where abouts are you based?

 

[knightime]

I'm in Worthing Howsie!

 

[mfgs]

I am down in Worthing for a couple of days next week. If you haven't got it sorted and you want another opinion I could stop by and take a look for you.

 

[Masood]

What I can't understand is why it worked for one day (the day the original plumbers left), but why the next day it failed!

If a lump of sludge or other debris was dislodged during the work they did, it may not have worked itself into a position where it could block the circulation until some hours later...

 

[knightime]

Fantastic mfgs - will keep you posted - thanks!

 

[knightime]

Thanks Masood - could be right there!

 

[Howsie]

I have Howsie - this is the 2nd plumber I'm on!

Same applies. Get a new one and lock them in until it's fixed.

 

[knightime]

I hear ya! This is the same plumber who replaced the pump and removed the trap - he's a really nice guy and open to suggestions, but seems to be stumped with this problem. If he's not able to rectify it tomorrow I'm gonna let mfgs take a look at it!

 

[Tonycane]

Sorted?

 

[knightime]

Re: All pipework replaced - still little to no heating downstairs ****FIXED****

***UPDATE - CENTRAL HEATING NOW WORKING!!!***

And...here's the culprit! It seems this bypass pipe was part of the original installation many moons ago, which explains a couple of things - a) why the heating took so long to get to downstairs prior to any work being done (lived with it for 16 years!) and, b) why the heating worked on day 1 after new pipework, but started failing the day afterwards!

The plumber said that the water wanted to travel the least distance it could, and as this 'loop' was directly above the boiler (under the bath and missed by the plumbers who put in the new pipework as they said they could access under the bath), it was pushing 85% flow through the bypass pipe, but only 15% to try and heat the whole house. This explains why the flow and return pipes connected directly to the boiler were roasting hot, but the return pipe that was cut and connected in front of the bathroom sink was cold. It also explains why the boiler was shooting up in temperature immediately the central heating was turned on.

So there you have it - we now have heating to the house that's better than it ever was, all thanks to this forum, my nosiness and a plumber who was willing to go that extra mile to help us out :hurray:!

Thank you guys so much for all your helpful advice and patience with this post - we got there in the end!!!

Warmest regards, Brian

 

[Tonycane]

Can't see the pic, glad it's been sorted. Seems obvious now

 

[rpm]

:hurray: :21: arty: arty: arty:

 

[oz-plumber]

Thanks for sticking with us over your issue and keeping us informed.

It's just woeful that the bypass valve was put in such a location.

Happy you got it sorted.

Even happier that you found a Plumber that was willing to work with you to try and resolve the problem.

 

[jonnyswamp]

Post no 58 3 weeks ago, lol
Glad it's sorted and keep hold of you're new plumber, he's worth his weight in gold

 

[Howsie]

Don't use this plumber or the other plumber again. Woeful.

 

[mfgs]

Glad you got it sorted, but it really shouldn't have taken this long to figure out.

 

[knightime]

Guys, you're all absolutely right - it should never have taken this long to rectify. The first plumbers kinda just wanted to get 'in and out' as quickly as possible, whereas the last plumber was open to all suggestions you posted on this thread, as well as humour my curiosity and look deeper into the problem. Defo a keeper :lol:! Thanks again!!!

 

[knightime]

Look for a manual bypass valve that maybe fully open
If there is one it should be near boiler/airing cupboard

jonny - we found it, and indeed it was the culprit! But it was underneath the bath and not in 'plain site'!

 

[Howsie]

Guys, you're all absolutely right - it should never have taken this long to rectify. The first plumbers kinda just wanted to get 'in and out' as quickly as possible, whereas the last plumber was open to all suggestions you posted on this thread, as well as humour my curiosity and look deeper into the problem. Defo a keeper :lol:! Thanks again!!!

How long did it take the last plumber to find it?