| Hi dac122, thanks for the reply.
You're definitely not the first to call me "long winded" :-)
There's only one way to describe something.... in infinite detail ;-)
IT has the YorkGuard VI Demand defrost board although I can't say if it's the new or old version. ( 069 vs 080) I'll have a look tomorrow.
EM heat selected on the T'stat has only the furnace running.
I see T'stat Aux heat indicator come on at various times , but it seems to make little difference to system operation, it' definitely the Defrost board controlling everything.
Seems York updated the low voltage wiring so your drawing number is more recent than the one I referenced
It's wired as per HP15A ( PV8 with YZB Hot heat pump enabled) I've triple checked the wiring from top to bottom.
I have an outdoor sensor on the way, but I'm still unsure how to add it ( for control purposes as opposed to just a temp indicator ) without loosing Hot heat pump mode.
I've fully documented the install with Pic's diagrams etc. (I'm a stickler for details , but do you think I wrote down the version number of the Defrost board ? DOH !)
Cheers
Gary  |