Main 24 HE DHW pressure?

[longdogs]

Hi

I went to change a bath filler for a customer today as they said that very little hot water was coming from it. When first opened, the water comes out fine but then reduces to a mere dribble. Basin taps and even kitchen taps are similar although not quite as obvious. Cold side of it fine.

It's as though the pressure builds up until the taps is opened and then pressure instantly reduces. Water is hot.

They have a Main 24HE combi boiler. When I mentioned my thoughts to the customer they said that the last time they had their boiler serviced, they thought the engineer had reduced the pressure to stop the boiler leaking??

I am convinced the problem is the boiler and not the taps and have told them to get a boiler man in but just wanted to ask if anyone had any thoughts on the subject. I don't want to charge them for changing the filler and it does'nt solve the problem.

Thanks.

 

[Agile]

If a boiler problem then the flow will be equally low at all hot taps.

You shsould measure in litres per minute!

Tony

 

[longdogs]

Thanks Tony

I can see that all taps are really slow without measuring the flow, bath filler is most affected. Can you explain why the engineer would have reduced the 'pressure' rather than fixing the leak? I think that's the bit I don't get.

thanks

 

[Agile]

People dont understand flow and pressure.

He may have reduced flow by partially closing the DHW inlet valve.

You can open that, fourth from left.

But he may have done that to cover up a blocked plate HE and the DHW results may be very poor.

Tony

 

[longdogs]

Thanks Tony

I came away a bit confused as language was a bit of a problem. I wasn't sure if it was the boiler leaking or maybe a fitting somewhere in the pipe work. They just said he 'reduced the pressure on boiler because it was leaking'. Now I know that it could have been the boiler, I will advise them to get someone in.

Cheers!

 

[Agile]

Pressure cannot be reduced, only the flow limited.

Any leak will be proportional to the pressure!

People get very confused about using slightly technical words like pressure and flow!

To me its simple and obvious!

Tony