Brand new heating system

[Oops123]

Hello, I am wondering if any of you knowledgeable people on here could give me some advice please.
We live in a 4 bedroomed house which is nearly 20 years old. We moved in 2 year ago and the hot water, water pressure has never great. The heating system in the house was the vented type with a water tank in the loft and a hot water cylinder in an upstairs cupboard. We have a main bathroom and an en-suite.
We decided to get a new combi boiler fitted ( Baxi 800 combi 2 ) and most of the radiators replaced as most of them were only single radiators.
So altogether we had 14 radiators replaced and a new combi fitted with Hive controls.
This system was recommended by our gas fitter.
Since this system has been fitted a majority of the downstairs radiators only get really hot at the top and the house is not much warmer than it was before. I would expect the house to be much warmer considering we have nearly all double convection radiators in every room now.
The gas fitter has been back on numerous occasions after we have told him about the issues. He has carried out balancing on a couple of occasions, done a full power flush with inhibitor added and none of these have made any difference.
Plastic pipe is used to feed the radiators (10 &15 mm) .
The fitter got paid straight away ( the job was finished end of September ) and seems to be lost for any kind of solutions to this problem now.
Have any of you came across this before as I would appreciate your help very much as I don't know which path to go down next.
Also with the weather the way it has been, it just seems like we have wasted our money.
Thanks very much in advance for any help you can give
Cheers.

 

[Deleted member 267285]

So if all are working upstairs, I would be turning these off at the trv to ascertain if the flow then is directed to downstairs only with results. If it does, then I’d say it is just balancing. If they don’t work, then you have a restriction somewhere.

 

[Oops123]

Cheers for that mate. Would the power flush not have dislodged anything stuck in the pipes or do you mean the pipe may be kinked somewhere. Thanks

 

[Deleted member 267285]

Could be kinked, could be stubborn blockage - depends if all new piping.

 

[MNW67]

Plastic pipe is used to feed the radiators (10 &15 mm) .

Isn't that quite restrictive. If you carry out the test suggested above and the downstairs radiators do actually get hot properly, could it be that the pump doesn't have enough power to feed all the radiators at once.

 

[Madrab]

1st question would be what size is the combi? How many bathrooms - with 14 rads it sounds like you are in a reasonably sized house.

As suggested, did they install new mix of pipework sizes? TBH though, the installers should be the ones to sort this out, you shouldn't have to resort to having to come onto a forum to get your system sorted, you paid good money and it should be working and be fit for purpose.

The only procedures anyone here would be able to talk you through should be exactly the same procedures that the installers should be doing to try and sort things out, with their eyes shut. Did the system ever heat up fully and properly, or did they leave it like that?

 

[Oops123]

Hello mate,
The house has one main bathroom and an en-suite in our bedroom.
As for the combi I'm sure it's a 30Kw
They mostly used the existing pipe work but moved the combi from the kitchen to the utility room ( only moved to the other side of wall where it was situated originally ).
Your right about coming on here and asking questions but I'd rather have some good info from you lads, when I have to go back to the fitter and start asking questions.
The system has never worked properly since the installation. I've had the Hive replaced and balanced twice. He tried to fob us off by telling us this was normal that radiators are boiling at the top and luke warm at the bottom in a new system but every person I know who has this kind of heating, has and even distribution of heat on the radiator.
Appreciate your answer mate thanks for taking time to help me out.

 

[ianmcd]

and most of the radiators replaced as most of them were only single

you cant just replace existing radiators with larger ones without correctly sizing the pipe runs to each rad

 

[Notch7]

Maybe the problem is pipe layout.

Older houses with a solid ground floor often have the main pipework spine put in under the upstairs floorboards and the down stairs radiators are fed by drops.

I've got that in my house and the groundfloor rads only work if the lockshield is nearly off in the upstairs rads.

I think you might want to try and work out how the pipework system is configured.

Maybe try turning off all the upstairs rads and seeing if the ground floor ones get hot.

 

[Notch7]

this was normal that radiators are boiling at the top and luke warm at the bottom in a new system

Thats Billy Bullsh1t

There is always a bit of temp variation but in the properly working rad there should be a temp gradient from one side to the other, not much top and bottom.

My guess if it's only hot at the top is the rads are getting almost no flow

 

[Oops123]

I'm no professional but that's exactly what I thought. The house is concrete floor downstairs, so I think what you maybe suggesting about the pipe work coming from upstairs will be correct. It's just frustrating the life out of me. If it hadn't been for some rooms being cold and poor hot water pressure, I think I should have just got a water pump and left the heating well alone. Thanks for the help.

 

[Madrab]

OK, as suggested, the installer cant just throw larger radiators onto the wall and hope they work, especially when they are fed by 10mm pipe. I'm taking a guess that the downstairs rads may be mostly supplied by the 10mm pipework? Can you confirm the make and size of the combi?

What is your largest rad downstairs on 10mm pipework > (Height mm x Length mm).

Also as suggested, the rads shouldn't be lukewarm at the bottom, yes they will be cooler but not lukewarm.

Unfortunately, it sounds like you have an installer that knows how to chuck a boiler on the wall but doesn't know the first thing about central heating design. A combi may not have been the best option either if you have 2 bathroom that may be used at the same time. Unfortunately you have also paid them in full, even though the system hasn't ever worked properly which isn't ideal either.

 

[Oops123]

Thanks for the reply,
Im starting to feel like a bit of an idiot, as I would have expected the fitter to know all of the requirements needed when installing the system.
I hope I haven’t been taken for a ride and the system is never going to run correctly.
I am away till next week but I will give you the info when I get back .
Cheers.

 

[Oops123]

Hello mate,
The biggest radiator downstairs 1600mm x 600mm double convector. The combi is a 30 kw Baxi 800 combi 2.
Cheers.

 

[Madrab]

The biggest radiator downstairs 1600mm x 600mm double convector

2.8kw rad ..... and that has 10mm feeds? Oh my ....