4 ton Carrier heat pump; about 12 years old. Suddenly tonight, no display on White-Rogers thermostat – doesn’t take batteries. Breaker is fine. Power good into unit.
But –
The multi-conductor control wire to the outside unit (on the roof, actually) has some probably squirrel-abraded places and general UV decay; bits of conductor showing. Noticed that last week, will replace it tomorrow.
No other wire has trouble – all exposed in the attic.
So –
Can an open or shorted control wire give me no display at all on the thermostat? (fan won’t come on in “on” – can’t remember if it did before).
After I replace that wire, I’ll be sad if it still doesn’t work.
Any wire pair to check voltage across on the thermostat?
Was looking forward to an easy night – middle kid projectile vomited last night so well I had to dissassemble our bed to clean it up. And hose it off a thick flokati with ice cubes from the hose outside
Then drove a float in the parade today.
It’s 22 outside, 47 upstairs. Nice down here.
Lots of feathers on the kids.
Forrest
Replies
Sorry to hear about the sick child.
No heat is not fun.
It has snowed about 20" of lake effect snow here with high winds and temps in the low teens.
Thankfully we have heat.
Good luck with the kid and the heat.
Russell
can you jumper across the appropriate terminals to turn the machine on? - a bit of manual operation tonight might ease the pressure -
or throw another log on the fire....
maybe - if i knew the appropriate terminals!
Forrest
Mc,Red (r) should be power, white (w) should be heat, may be yellow(y) for heat pump. (E) for emergency heat.KK
Checked those at the T-stat - no nothing between any pair. Replaced the squirrel-chewed control wire on the roof to the unit. Still no.
Pulled the panel off the air-handler . . .
Yay! Blown ATO 5A fuse on the control board! Changed it, reset the T-stat, everything wonderful.
Yay! Heat in the bedroom tonight!
Forrest - unreasonably pleased
Worked on a unit where a bulldog chewed through the LV wire to the compressor. There was no 24v at the transformer, so I put in a new transformer. Which started smoking immediately because the wires were still shorted. OOPS! Well the new transformer survived ok, so the moral of the story is check the wiring before putting new parts in.
I think you may just have an open to the transformer to the thermostat, since it doesn't show a display. It's also possible the thermostat died. Like others said, see if you can jumper it on.