Downstairs radiators not warming well

[bewsh]

Alright guys?

A mates parents are having trouble with their radiators down stairs. The boiler is a Baxi Combi 80HE, I've changed the pump and balanced the system, but the problem is the same.

I think the pipework is undersized so not getting enough flow, what do you guys reckon?

The boiler is upstairs, flow/return come down the wall of the lounge in 22mm then reduced to 15mm hep under the crawl space below the lounge, this 15mm is then feeding all of downstairs, a total of 5 radiators, all large doubles, 3x 1800, 2x 1400 radiators.

I've told him that 15mm hep has an even smaller internal diameter, and suggested re-piping in 22mm.

Any other problems I should be looking at before re-piping it?

Cheers!

 

[joni os]

Old rule of thumb:- 15mm pipework good for up to 15,000 Btu. Extend flow and return in 22 mm. and flush system whilst you are drained down.

 

[Simon F]

has it always been a problem?
or has it developed?
does sound undersized on the pipes

 

[bewsh]

All worked previously, it was my mates grandparents house before. But all radiators, valves and downstairs pipework was renewed by some company.

 

[jtsplumbing]

Have you had valves off ground floor rads see if any crap stuck in them ??

 

[gassafe]

All worked previously, it was my mates grandparents house before. But all radiators, valves and downstairs pipework was renewed by some company.

Always frustrating when they say it all worked fine before... It makes it harder for them to understand the need for us guys to upgrade / replace pipework!!

 

[quality]

There is an estate where I am that have 8mm to the rads and work to an acceptable degree, maybe a restriction somewhere

 

[Matty7]

How about trying a flush through of the system? Like above posts said maybe a restriction, sludge etc!

 

[bewsh]

Nah system has already been flushed.

I'm going to just chuck 22mm circs in the crawl space downstairs, I had another look and they have used the coils of 15mm hep, so it's all over the place, so going to use straight lengths this time.

 

[Jay Jay]

It may have been flushed but all the crap may be on the downstairs circuit ,yes putting bigger pipe will help but if it's microbore unless you flush with an immersion heating element on flushing machine this will confirm rad temp--I don't understand why people don't use them as using the boiler drags muck in to main hex etc

 

[gassafe]

It may have been flushed but all the crap may be on the downstairs circuit ,yes putting bigger pipe will help but if it's microbore unless you flush with an immersion heating element on flushing machine this will confirm rad temp--I don't understand why people don't use them as using the boiler drags muck in to main hex etc

Use a filter with your machine... Will catch it for ya...