No HW when CH is on

[roberta1000]

I have a bungalow. The HW is gravity feed (no thermostat or valve), the CH is pumped. When the CH is on the HW is very slow to heat or doesn't heat at all. When the CH thermostat turns off the HW is fine. I guess there isn't enough convection for the HW system with such a low ceiling. What can I do?

 

[bengasman]

this is normal for an ancient system

 

[roberta1000]

Yes, well, fine thanks, but what I asked was "what can I do". My previous house had the same sort of setup but it was 2 storey so there was plenty of convection for the HW generally.

For instance can I simply repipe it so that the HW is in the pumped circuit instead of convecting? A new system is out of the question.

 

[gasandoilman]

You can fit a new 2 port 28mm valve to a new pump and cylinder stat

i see a lot of two pump systems on old oil heat systems

but re-piping is the best way

 

[gasandoilman]

why not convert to a fully pump system

 

[bengasman]

best value for money is to convert to y-plan, depending on where you are i would expect around 300 pound to solve the problem

 

[DP]

Simplest answer would to fit an independent timebase programmer like Danfoss FP75. Heat the water from 4.00am to 6.00am, heating from 6.30 to 8.30am. In other words heat the water when heating is not required.
Installing a two port valve (must be sited correctly so as not to block feed or vent pipe) in HW circuit will lead to fuel economy.

 

[gasandoilman]

wouldnt a c plan be cheaper?

 

[DP]

First part of my post only requires the programmer to be replaced to achieve the result the OP is looking for.

Second part is in fact the C plan.