Unvented cylinder and adding a thermostate

bobster2543

I have a unvented cylinder heating system with 2 zones for the rads.

I have 2 wall Thermostats for the rads and also can either have the rad zones off or on with a switch . When both zones are off and the boiler is on the water diverts to the cylinder coil, I cant stop the water from heating the cylinder as there is no mortizesd valve and thermostate fiited to it. I was told by the plumber who fitted the system that I can't have a thermostate for the cylinder as the water has to loop around the system. Ie. He basically said. If the 2 zones vavle were closed, with a closed valve on the cylinder and the boiler was on it would not be good for the boiler. As the water as to loop around the system.

Is this correct or is that bullshit?

I would like to fit a new control eph rf programmer and thermostates and a thermostate for the cylinder.

John.G

BS with a capital B. A automatic bypass valve (ABV) which will open when required can be installed with the programmer and motorized valve+cylinder stat.

bobster2543

Thanks John that's great, I thought it was a bit strange. He probaly could be arsed fitting one.