Potterton Puma 80E - lukewarm water to bath and shower

[carlm]

Hi

I have a newbie question. I have a Potterton Puma 80e, which was recently serviced.

Central heating is fine, and hot water to basins is fine. However, when using the shower or the bath, the water only gets lukewarm. It's piping hot out of the basin taps in the same rooms.

We replaced the hose and mixer in the aqualisa shower following their advise, but no change.

I've looked at previous posts on this forum, but I haven't found a topic with a problem quite the same as this. Any thoughts anyone?

Many thanks

Carl

 

[baxpoti]

Two things, to check
your running the bath faster than the boiler can keep up with
or the hot water is being blended with cold at the mixer

 

[g60bv]

agreed.
if you have hot water out of one tap. unless your plumbing is really screwed up. it should deliver the same to the other hot taps. try adjusting the flow down on high flow taps. - baths.
do you know if you have an anti-scalding valve in the bathroom. ?

 

[carlm]

Hi

>>hot water is being blended with cold at the mixer

I don't think it's this, as the problem happens with the bath and the separate shower (en-suite) which would imply 2 defective mixers? They're both new too. I can't readily isolate the cold at the shower. Might be able to at the bath though.

>> try adjusting the flow down on high flow taps. - baths

If I turn the bath or the shower flow down really low the water does get very hot. However, turn the flow up and down goes the temperature. For example, on the shower, with the mixer turned as far to the right as it will go, if the flow is a gentle spray it's hot, but any pressure and it goes lukewarm. It's not a power shower, so nothing too demanding I wouldn't have thought.

>>do you know if you have an anti-scalding valve in the bathroom?
Not as far as I can tell. Nothing on the DHW outlet from the boiler and nothing leading to any hot taps

So that sounds like I am trying to draw hot water faster than the boiler can cope with. Can this get worse with time as a result of something wearing out or failing?

On the boiler, I've always though that the upper temperature control dictates the maximum temperature. I've upping this but it made no difference to this problem. Should it?

Another thought - the boiler is fed straight from the mains - would that mains water pressure have any effect?


Thanks again
Carl

 

[Agile]

Your 24 kW boiler can only heat about 8 litres per minute to a temperature that you cannot keep you hand in for more than five seconds.

I am sure your boiler is fine but if you still think there is a fault then measure the flow rate and tell us!

Most thermostatic showers mix about 10% of cold water with the hot. That does not go well with a combi boiler.

Tony