I have a gravity hot water & central heating system with a rather strange (from what I can see) setup. The hw cylinder has the standard thermostat attached to it which operates a 2way valve, when the tank reachs the set temperature. Unfortunately when the valve closes, this also causes the central heating to stop. The ch pump is still spinning (if room thermo wants heat) but it seems that no water is flowing round the circuit as the rads go cold and the pipe leading to the pump goes cold as well. Almost as if the circuit for the ch is shut as well.
I have attempted a bodge, by turning the boiler gas control down, and turning the tank thermo up high, so that the 2way valve does not close easily. This all works fine, as long as some hot water is used, and the house is fairly cold requiring ch. Else I get into a loop of waiting for the tank to cool enough to open the valve, and thus give me some ch.
Can anyone think of something I can do to remedy the situation ? Can I put a link into the output from the room thermo that will open the
2way valve if ch is required, or will this cause problems ? If so which of the 5 wires on the valve would need to be used ?Thanks in advance
Paul..