hw/ch problem

[mrblobby]

Hello hope you can help. I have a hw system that regularly has been tripping the whole house elec circuit on firing up. I thought the programmer was to blame which i replaced. Still no change. I tried isolating everything and believed the problem to be the cylinder stat. Which i have also replaced.
The system still trips, but now however if system is switched on when I have the cylinder stat down on it's lowest setting, and then I turn the stat up, the hw system doesn't trip and the boiler lights up. The CH also will not work without doing this with first.
What does this indicate ?

 

[EliteHeat]

A faulty motorised valve? in a fully pumped system the CH should come on independantly of the HW. A quick check for 230v to the grey plus white wires to the 3PV (if you have one) should confirm this.

If the grey voltage is low it will prevent the microswitch from operating, I would suspect the programmer if this was the case. If you're getting the correct voltage and the orange wire does not become live suspect the actuator.

 

[mrblobby]

thanks. i will check it out tonite. I don't think it can be programmer as this has already been replaced with new. The lever on the valve does seem to switch as it should between h-m-w, so i though this means that it is working ok.

 

[MANDATE]

Moving the valve with lever does not mean it's ok. The valve is moved with a motor, so either motor no good, wiring to motor wrong or failed microswitches