Boiler Issue - Reduced Flow of Hot Water

jonny2510

We have an oldish combi-boiler (Potterton Puma).

Recently, when filling the bath, the hot water has come out really slowly (nothing else using the water at the same time), then full flow for a few seconds, then slowly again for a while, then fast again etc.

The shower (not electric) has now started behaving similarly - reduced flow/scolding hot, then normal, then cool, then scolding again (it's never done this before)

Does this sound like a common problem, that I can fix, or am I going to have to call a plumber out

HandyMan

What's the flow rate like at the other hot water draw off points?

cyclonebri1

You will need to call someone in. There is a valve that diverts the hotwater to the hot taps on demand and is probably not operating correctly.

You can prove or rule this out.
1st determine which is the HW flow pipe at the boiler
then determine the CH flow pipe.

Let everything cool down and switch a HW tap on full. If you get any heat into the CH flow pipe, the problem is likely to be as suggested. It could be other things but then you will definately need assistance. I only suggest this as the house my daughter bought last year had a 13 year old combi which did exactly the same and eventually gave no HW but all flow into the CH. :money:

jonny2510

HandyMan wrote: »

What's the flow rate like at the other hot water draw off points?

All affected I think.

The kitchen sink *seems* to take longer to fill.

The bathroom tap seems to go scolding hot(with reduced flow), much quicker than usual (too hot to wash hands under - which hasn't really been a problem before)

cyclonebri1 wrote: »

You will need to call someone in. There is a valve that diverts the hotwater to the hot taps on demand and is probably not operating correctly.

You can prove or rule this out.

Thanks, I'll give this a try. At worst, it'll help the engineer in diagnosing things quicker.

Many thanks for the responses.