Boiler HW/CH controls (Ed.)

[Bracken99]

I have a Worcester Greenstar Heatslave External Boiler model 18/25 and the heating is being temperamental.

I suspect the problem is the diverter valve but I am not sure.

When I have had problems before, I run the hot water until the boiler kicks in and normally the heating will come on. But this is not happening now.

However the following is confusing me further.

Within the boiler there are two rotating switches which control and set the temperature of the water and the radiators. The hot water I have set at 10:00 o’clock, the heating at 12:00 o’clock. (In both cases low is 09:00 o’clock and high is 03:00 o’clock).

So I run the hot water and the boiler starts and whilst it is running I dial down the temperature of the heating and the boiler switches off. I turn up the heating temperature and the boiler comes on. However the diverter valve is still giving priority to the hot water. Why is this so? While this is going on the house thermostat is calling for heat.

I full accept I will probably need to engage a heating engineer but this being Christmas that could take a few days.

I am no techie but any advice would be helpful.

Thank you and a Merry Christmas!

 

[Burnerman]

The Heatslave tank must be satisfied with hot water before the heating will kick in.
Domestic hot water always has a priority with these boilers and when you turn the hot tap on a flow switch recognises this and starts the burner up.
Just set your thermostats at 12 o’clock and see how things go.
John

 

[Bracken99]

John,

Thank you for your prompt response. Particularly on Christmas Day! I will do as you suggest.

I was aware the hot water takes priority but I am still puzzled. When I have had this problem previously I have run the hot water tap to fire up the water and when the water is up to temperature the heating then kicks in. However recently that has not happened.
What happened yesterday was that when the boiler was running, and while the diverter valve was switched to hot water, I turned down the dial for the heating temperature and the boiler switched off. Why should that be the case when the water hadn’t come to temperature?

Once again, thank you for responding.

Chris.