Potterton combi 80 boiler hot water flow

[Bloggsyboy]

Hi again, (long time away), I recently fitted a new monobloc kitchen tap.
I have found that when you fully turn on the monobloc hot tap the boiler does not register that it needs to turn on. If you then go and turn the utility room hot tap on and off again with the kitchen one still on, this allows the boiler to supply the kitchen tap. Do you knowledgable lot know if there is adjustment in the boiler to say what flow from the tap starts it off? I think this is the problem we have been having with the upstairs shower as if you turn the heat down it goes cold as if the boiler has switched off due to low demand.

 

[lexington]

Hi ,
If you have a fitted a new tap it could be that it has the smaller type flexi hoses fitted to it, they will slow down the water flow and can cause the boiler not to fire. I have a customer who installed a new mixer tap, and since it was installed it will not activate the boiler for hot water, but every where else is ok. If it is not the tap, then you can adjust the flow switch on this boiler,
if you look at the dhw diverter, you will see the microswitch assembly, which is held in place by a lock nut. You need to take the wires off, undo the locknit and move it closer to the spindle which activates it. However it may be that the diaphragm is wearing out and if so, will need replacing.

Hope this helps.

 

[Bloggsyboy]

Hi, thanks for the advice, yep the new tap hoses are smaller. We have a British Gas service contract, they may come and adjust this thing for us as I'm afraid of messing things up, we could get then to check the diaphram too (whatever that is). By the way, where is the bhw diverter and what does it look like?

 

[lexington]

You are right not to mess around with it yourself, get british Gas to look at it, but just for your info it is behind the front cover on the left hand side, brass with a microswitch with 2 wires going to it, cannot remember the colours off hand, yellow or orange I think.

 

[Bloggsyboy]

Thanks for the advice. I'll do just that.

 

[Agile]

What he is describing is not a diverter valve but the DHW flow switch. That should operate at a flow rate of about 2.5 li/min.

You should measure the flow rate from your kitchen hot tap. If its less that 2.5 li/min then its not going to give you much water flow for the sink.

Tony