Myson 2 zone heating problem

[Carl 90]

Good evening people, having a very frustrating couple of days!! The problem is as follows.

If i put the Downstairs thermostat on override. Operating light on mpe222 valve. Boiler fires up. Heating supplied to downstairs.

Then override on upstairs thermostat, this puts on operating light and get heating upstairs. Can cycle it on and off whilst down stairs thermostat is on. If down stairs is knocked off, upstairs thermostat still Carrys on heating as it should but if you turn off upstairs thermostat when downstairs stat is off, the operating light goes off on the motorised valve and you hear it close. You cannot get the heating to come back on upstairs unless you. re select downstairs thermostat to on.

If you select heating for upstairs whilst downstairs is off, no operating light comes on or no valve opening no boiler activation and no heating.

Surely this isn't right. That is the whole point of a 2 zone system? House was built in 2013 and has a combi boiler.

It's almost as when nothing is on and you select upstairs heating on, no signal (hardwired) is reaching the motorized valve which in turn isn't firing up the boiler. But it works if down stairs heating is on.

Anyone help?

 

[jeff the gasman]

Sounds like a faulty end switch on the upstairs valve. Especially if it’s worked before.
New actuator should sort it.

 

[Carl 90]

Thanks for the reply,

Even though it works fine when the downstairs heating is on?

 

[jeff the gasman]

The downstairs valve is providing the end switch.

 

[Carl 90]

So a replacement value head should sort the issue?

 

[ianmcd]

yes