Boiler does not turn on for hot water

Krakkkers

If it were a stuck valve the the boiler would still kick in to try to heat water.
So it must be thermostat or the hot water is already above the desired temperature.

robshak

One comment - 30KW boiler just for central heating and a hot water tank !!! You probably only need ~14KW unless you have a mansion to keep warm.

Ha ha..not really a mansion (4bed approx 200sqm) but the previous owner did some upgrades..yes 30kw hits the pocket hard when the heating has to go on..thanks for the advice on electric connection..will shut if off at mains and check..any way to identify if it is blown?

robshak

Krakkkers said:

Is the water hot or cold at the moment?

Cold..tolerable for now due to this extended summer..but not for too long :

[Deleted User]

Krakkkers said:

If it were a stuck valve the the boiler would still kick in to try to heat water.
So it must be thermostat or the hot water is already above the desired temperature.

Not necessarily, it depends on the installation wiring:

‘When the valve is turned on and finishes opening, it triggers the switch to turn on the pump and/or boiler to push water through. Otherwise, this wiring is in series with the valve on/off signal.’

Krakkkers

Surely your water is above 25? try setting it to 60.

robshak

Krakkkers said:

Surely your water is above 25? try setting it to 60.

As I mentioned before, I think this temperature control thermostat is for central heating (only goes to 30).  Not sure where the temperature control for hot water is, perhaps inside the OSO tank console..still to open up the panel and check for a broken thermostat for the hot water tank..the thing is, I never had to adjust the hot water temperature before the system malfunctioned.

QrizB

robshak said:

Krakkkers said:

Surely your water is above 25? try setting it to 60.

As I mentioned before, I think this temperature control thermostat is for central heating (only goes to 30).

The Honeywell-branded knob on the wall is your room thermostat. It controls whether the heating system calls for heat, or not.

There will also be a tank thermostat that controls when the HW tank calls for heat.

The times that the HW tank and/or the radiators are allowed to be heated by the boiler are controlled by the Horstmann programmer.

The flow temperature of the water in the heating circuit is controlled by the left-hand grey knob on the boiler, the one with a picture of a radiator next to it. It is highly likely that this also controls the temperature of the water flowing through the coil in your indirect hot water tank.

The right-hand grey knob on your boiler (the one with a picture of a tap next to it) would control the temperature of the hot water in your taps, if the taps were being fed direct from the combi boiler rather than from the hot water tank.

How much fault-finding are you prepared to do? Would you like us to talk you through it?

robshak

How much fault-finding are you prepared to do? Would you like us to talk you through it?

That is some really good information. Thank you. There seems to be a lot to learn.

I am definitely into fault finding. It would indeed be very helpful if you could talk me through what I should do?

Krakkkers

Find the thermostat on the hot water tank would be my first move.

Ectophile

robshak said:

One comment - 30KW boiler just for central heating and a hot water tank !!! You probably only need ~14KW unless you have a mansion to keep warm.

Ha ha..not really a mansion (4bed approx 200sqm) but the previous owner did some upgrades..yes 30kw hits the pocket hard when the heating has to go on..thanks for the advice on electric connection..will shut if off at mains and check..any way to identify if it is blown?

Do you normally leave the boiler's central heating temperature set to maximum?  If so, that won't be helping your gas bills.