Potterton Netaheat No Hot Water

I went to have a look at a customer's system who wasn't getting any hot water. The customer said that the water was not working at all, and had been working irregularly fora week. Sometimes, he would have plenty of hot water, other times none, and sometimes only lukewarm.

I switched the hot water on at the programmer, and ensured the hot water thermostat was turned up fully as the immersion heater had been on earlier. The system was had two zone valves and I checked the voltages at the junction box. There was power at the grey wire and the brown wire, but no power on the orange wire. The Honeywell V4043H zone valve was partially open looking at the manual lever but not fully. I removed the head from the body and felt the spindle. The spindle was not moveable by hand, and the cause of the problem.

Fortunately I could isolate the zone valve by switching off the pump valve, bypass valve and gate valve on the hot water return. Due to the location of the zone valve it would have been awkward to replace the whole valve, and so I removed the 'paddle' plate by undoing the four bolts. I replaced the o-ring and 'paddle' plate before opening all the valves isolating the zone valve. I wired in a new valve head before fitting it to the 'new' body. I tested the hot water system and it was all working well.

Disclaimer: The works described in this blog are a record of work undertaken and should not be taken as guaranteed to solve your problem. Work should only be carried out by persons qualified and competent to do so.