Hot water is not circulating through the radiators.
Hot tap water is fine, pump works and the boiler works fine.
I've over-ridden the clock, i.e. CH is on constantly.
I've set the thermostat to 25° with the ambient temperature around 15°, and it indicates "On".
The motorised valve (a standard V4073a) does not seem to work.
If I push the lever to open the flow to the central heating, the pump does not start, nor does the boiler fire up.
However, if the pump is running to heat the hot water, leaving the valve jammed open allows water to flow through the radiators.
When the water in the cylinder reaches the required temp, pump switches off and boiler shuts down.
Where do I start looking?
The thermostat or the motorised valve? Or could be somewhere else?
Can anyone point to simple to test of the motorised valve?
Many thanks, John.
Hot tap water is fine, pump works and the boiler works fine.
I've over-ridden the clock, i.e. CH is on constantly.
I've set the thermostat to 25° with the ambient temperature around 15°, and it indicates "On".
The motorised valve (a standard V4073a) does not seem to work.
If I push the lever to open the flow to the central heating, the pump does not start, nor does the boiler fire up.
However, if the pump is running to heat the hot water, leaving the valve jammed open allows water to flow through the radiators.
When the water in the cylinder reaches the required temp, pump switches off and boiler shuts down.
Where do I start looking?
The thermostat or the motorised valve? Or could be somewhere else?
Can anyone point to simple to test of the motorised valve?
Many thanks, John.