Hello Everyone,
Perhaps you can help me identify what might be the problem with my central heating. The upstairs radiators behave normally but downstairs take time to get warm and don't get really hot unless upstairs are shut off. The more upstairs radiators that are switched off the hotter the downstairs ones get (mainly at the top...the bottoms can still be cool). My old boiler broke down too many times so I recently had a new one fitted. The radiator problem developed over time prior to getting the new boiler.
I've read a lot on-line so I know that you will need a lot of info to help with the diagnosis. I will set out some bullet-points below so I don't tie myself up in knots trying to tell the story.
Facts....
1. Normal two storey oblong-shaped house (approx 15 years old) with longest walls front and back.
2. Airing cupboard on landing fairly central but nearer to the front of the house.
3. Nine downstairs radiators and eight upstairs.
4. New Grundfos Alpha 2 Auto Adapt Pump fitted upstairs in airing cupboard several months ago. BG Engineer said the old one was gunged-up and recommended a powerflush. He also said I had too many by-passes in airing cupboard and recommended removing two of them. No other engineer (and many have visited over the years) ever mentioned this. I didn't take him up on his offer due to the £800 cost.
5. New W/Bosch 24Ri (Heat Only) Boiler very recently fitted in utility room downstairs. Chemical and power flush carried-out and magnetic filter fitted. I was told that system was pretty clean in any case. Took time to get all rads working as before but eventually chased the air out.
6. Sealed system. Pressure gauge normally hovers around 1 bar.
7. All radiators have TRVs except one in hall and one on landing which have normal wheel valves (another two by-passes apparently).
8. Dot and Dab walls with 10mm pipes feeding each radiator. One pipe each side.
9. I've bled radiators, checked the pins under the TRVs are free and closed the upstairs lockshields to approx half-turn from closed. I set the downstairs lockshields to between one turn and fully open depending on how warm they got.
10. Upstairs the feed pipes to the radiators get really hot really quick (as do the radiators) and the return pipes are marginally cooler. Downstairs it takes a while for the feed pipes and radiators to get warm/hot and the return pipes remain quite cool.
Assumptions....
1. Having reads lots on helpful forums like this and speaking to the guys who installed my new boiler I now think the radiators are fed via manifolds.
2. In my mind I assume that there are four manifolds. One feed and one return for upstairs and the same for downstairs.
3. If these assumptions are correct then it would seem there is a blockage in the downstairs return manifold or in the return pipe leading away from the manifold. That would mean that there is little or no flow through the downstairs radiators and the heat they eventually receive is by conduction or convection.
Questions....
1. Are my assumptions probable?
2. Given that the manifold and return pipe away from the manifold would be of wider bore than the 10mm pipes to and from the radiators, would it be likely to block whilst the smaller bore pipes remained clear? Then again, it would be too much of a coincidence if all the 10mm return pipes to the manifold had a blockage.
3. I assume the manifolds (if I have any) would be under the the floor on the landing. Is lifting floorboards the only way to find them? Are they likely to be anywhere else?
4. If my assumptions are correct, is it also safe to assume that the ground floor radiators did not benefit from the chemical and power flush?
Sorry if this story is long-winded but I'd be very grateful for any and all answers and comments that could help me resolve this issue. I probably wouldn't tackle this job myself but if I can make a reasonable diagnosis and find the manifold (if there is one) then I could save myself a lot of money.
Thanks in advance.
Perhaps you can help me identify what might be the problem with my central heating. The upstairs radiators behave normally but downstairs take time to get warm and don't get really hot unless upstairs are shut off. The more upstairs radiators that are switched off the hotter the downstairs ones get (mainly at the top...the bottoms can still be cool). My old boiler broke down too many times so I recently had a new one fitted. The radiator problem developed over time prior to getting the new boiler.
I've read a lot on-line so I know that you will need a lot of info to help with the diagnosis. I will set out some bullet-points below so I don't tie myself up in knots trying to tell the story.
Facts....
1. Normal two storey oblong-shaped house (approx 15 years old) with longest walls front and back.
2. Airing cupboard on landing fairly central but nearer to the front of the house.
3. Nine downstairs radiators and eight upstairs.
4. New Grundfos Alpha 2 Auto Adapt Pump fitted upstairs in airing cupboard several months ago. BG Engineer said the old one was gunged-up and recommended a powerflush. He also said I had too many by-passes in airing cupboard and recommended removing two of them. No other engineer (and many have visited over the years) ever mentioned this. I didn't take him up on his offer due to the £800 cost.
5. New W/Bosch 24Ri (Heat Only) Boiler very recently fitted in utility room downstairs. Chemical and power flush carried-out and magnetic filter fitted. I was told that system was pretty clean in any case. Took time to get all rads working as before but eventually chased the air out.
6. Sealed system. Pressure gauge normally hovers around 1 bar.
7. All radiators have TRVs except one in hall and one on landing which have normal wheel valves (another two by-passes apparently).
8. Dot and Dab walls with 10mm pipes feeding each radiator. One pipe each side.
9. I've bled radiators, checked the pins under the TRVs are free and closed the upstairs lockshields to approx half-turn from closed. I set the downstairs lockshields to between one turn and fully open depending on how warm they got.
10. Upstairs the feed pipes to the radiators get really hot really quick (as do the radiators) and the return pipes are marginally cooler. Downstairs it takes a while for the feed pipes and radiators to get warm/hot and the return pipes remain quite cool.
Assumptions....
1. Having reads lots on helpful forums like this and speaking to the guys who installed my new boiler I now think the radiators are fed via manifolds.
2. In my mind I assume that there are four manifolds. One feed and one return for upstairs and the same for downstairs.
3. If these assumptions are correct then it would seem there is a blockage in the downstairs return manifold or in the return pipe leading away from the manifold. That would mean that there is little or no flow through the downstairs radiators and the heat they eventually receive is by conduction or convection.
Questions....
1. Are my assumptions probable?
2. Given that the manifold and return pipe away from the manifold would be of wider bore than the 10mm pipes to and from the radiators, would it be likely to block whilst the smaller bore pipes remained clear? Then again, it would be too much of a coincidence if all the 10mm return pipes to the manifold had a blockage.
3. I assume the manifolds (if I have any) would be under the the floor on the landing. Is lifting floorboards the only way to find them? Are they likely to be anywhere else?
4. If my assumptions are correct, is it also safe to assume that the ground floor radiators did not benefit from the chemical and power flush?
Sorry if this story is long-winded but I'd be very grateful for any and all answers and comments that could help me resolve this issue. I probably wouldn't tackle this job myself but if I can make a reasonable diagnosis and find the manifold (if there is one) then I could save myself a lot of money.
Thanks in advance.
