Central heating not firing up is controller at fault r

[Kevin gambler]

Renewed room thermostat and 3 port valve(drayton MA1) but hot water fires up OK but not central heating unless I turn off hot water timer settings on drayton lp522 controller?

 

[king of pipes]

Recheck your wiring Chance's are theres a wire in a wrong place

 

[Ziggie]

The Y system requires 3 wires on cylinder stat (common, hot water requested, hot water not required) and wiring from hot water not required on programmer as well as hot water required. The 3 port doesn't select "heating only" without the "hot water not required" connections.

As above, check your wiring including above
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Given your description, my first guess on wiring to check is
Hot water cylinder (hot water not required) to grey wire on 3 port valve .
Wire from hot water not required on programmer to grey wire on 3 port valve.

Please check that I have got the wiring correct as I'm doing this from memory!

 

[Kevin gambler]

Thanks for replying.. I'm going to recheck all the wiring today.. This all started over a failed room thermostat and the new one shows voltage when calling for heat and 0volts when not so that works.. I will check wiring centre in airing cupboard but at controller end it is buried in the wall in a huge ball! I will report back my findings later as I'm a DIY but I do have engineering knowledge.

 

[Ziggie]

Thanks for replying.. I'm going to recheck all the wiring today.. This all started over a failed room thermostat and the new one shows voltage when calling for heat and 0volts when not so that works.. I will check wiring centre in airing cupboard but at controller end it is buried in the wall in a huge ball! I will report back my findings later as I'm a DIY but I do have engineering knowledge.

Remember as I am sure you know, somewires are 240volts even when no demand

Since it works when. You turn timer off - I think that programmer is wirded ok.

 

[Ziggie]

Can we assume this incident is closed?
It would help if you could say what the problem turned out to be as it then serves as an example for others.