Quote Originally Posted by ROBBIE123 View Post
Hi to all.

thank you for all your help.

I have had no luck. I just managed to get to the unit, replaced the thermostat, have given it a test, and it does not seem to make any difference. but when the stat is turned manually from +30 to -30 it kicks in and starts working.

I have changed the stat, defrost timer is fine, and is working as should.

any ideas on where I could check?

thanks, much appreciated.

rob
So you have swapped out the stat and the system is behaving the same way or differently?

Where have you positioned the sensor bulb? You mention that the system starts when you turn the stat down in temperature? Have you wired the stat correctly to make on the rise? It sounds as though it is making on the fall? Why does the stat have such a big range? (+30 to -30) select a stat with a smaller range suitable for your case. So if set point is 0degc +5 to -5 stat would give you far more accuracy to set up correctly.

Also, the stat shown in your picture above looks as though it could be a defrost termination stat rather than a control stat? If this was the case, then decreasing the set point as you have described whilst on a defrost, would terminate defrost and start the system. Just an idea...

I would imagine the case is on a pump down, find the solenoid valve and work back to where it gets it's feed.