Intergas HRE 36/30 - Luke warm water (DHW)

[jc001]

Hi, hope someone out there can help.

Our 8 year old Intergas HRE, serviced annually has started to deliver luke warm (30-degree-ish max) water on DHW. I am located in a hard water area, south Bristol.

From what I can tell..

• Flow switch works (you can hear the 'click' when opening a tap to say 10% of full)
• Boiler has the ability fires at max - confirmed via test mode
• Water pressure and flow appear normal.
• You can run the boiler on max, in test mode, and only luke warm water comes out of the tap (this might be by design?)
• When you fully open the HW tap, the boiler fan does not seem to go to max - perhaps 60% of max.

Can any of the experts provide an insight as to what might be the cause before I call the chap who does the servicing; everytime he comes round he says he does 'not really like this boiler!'

I am thinking faulty temp sensor on DHW, scaled heat exchanger, or fried PCB.

Thanks in advance

 

[picasso]

I would be looking for a passing shower valve or mixer as it sounds like your boiler is doing what its supposed to.

 

[jc001]

I would be looking for a passing shower valve or mixer as it sounds like your boiler is doing what its supposed to.

Many thanks, but sorry, what do you mean? The problem seems to exist at all taps in the house. Can you expand?

 

[picasso]

If your boiler is ramping up to about 60% you would get more than 30c out of a tap, I reckon a non return valve is stuck open on a shower or tap mixer which lets cold water mix with the hot, try running a hot tap and feel the hot water outlet under the boiler and see if that is tepid.

 

[muggles]

Most likely to be scale if there's no scale protection. The temp sensors on these are very reliable. Sounds like you might be in need of a new service engineer who is familiar with these excellent boilers. You've got Gary Belgium of Hengrove Heating if you're in South Bristol, or Jon Williams of Bristol Gas Services. Both will provide you with a first rate service

 

[jc001]

If your boiler is ramping up to about 60% you would get more than 30c out of a tap, I reckon a non return valve is stuck open on a shower or tap mixer which lets cold water mix with the hot, try running a hot tap and feel the hot water outlet under the boiler and see if that is tepid.

It looks like you are right. With an IR thermometer I have measured the DHW on exit from boiler - 60deg. At the kitchen tap, about 2 metres away its 40deg.

We have a mixer shower upstairs and the mixer knob has been gradually loosing all its resistance, suggesting something is not right there. Ill isolate this and see what happens.

 

[jc001]

Amazing fixed! A mixer in the bathroom (not the one I hinted that could be faulty) was turned to full-cold and as picasso rightly suggested, was somehow diluting the hot. Turned to normal temp and voila, hot water as normal.

Thanks very much @picasso

 

[picasso]

Your welcome.