Hi. I decided today to replace the old mercury thermostat with a new
digital one. I turned off the breaker, removed the the old one,
labelled all the wires, and installed the new one. When I attemped to
start the heat, nothing happened. After I rechecked my work, I
re-installed the original one. Now that does not work either.
Switching the fan to on and trying emergency heat does nothing as well.
My heating system consists of an outside york heat pump, an inside
york blower, and a hyrokinetic unit. The hydrokinetc unit appears to
working fine, as the pipes are too hot to touch and it kicked on a
little while ago. My assumption is something is wrong in the
connection between the thermostat and the blower or some part failed.
Can anyone provide any insight? Since its Saturday, I'm probably stuck
until Monday. Hope it doesn't get too cold. I have some qualified
help coming over tomorow, but maybe I can get some ideas of where to
Thanks for the help. The fan unit is model #N2AHD10A06A. The manual
for the outdoor covers models E1EB0xA06, where x could be 18, 24, 30,
or 36. I flipped the breaker off in the fuse box before I started.
Thanks for taking the time to provide so much information. I
appreciate the advice. I am going to leave it alone for now and save
this for tomorrow, when someone far more knowledgable than me about
electricity and hvac will be here to take a look. Thanks again.
There are no LEDs at all on the blower unit, at least not that I could
find. There are a couple of components behind the panel inside the
blower, maybe one is the transformer you mentioned? I'm crossing my
fingers I can get through this for less than $500. And this will be
the last DIY project where this much is on the line. I'll stick to
what I know. Thanks.
If you have a FRP airhandler you blew the fuse on the control board.
You did cut the power off at the airhandler when you started this didnt you?
If its not an FRP airhandler, post the model and serial of the York
airhandler (blower) AND the outside York unit, and I will pull up a diagram
and find out what you MIGHT have fried if you didnt turn the power off at
Thats a old early 90s blower that has no fuse, or board in it.
Not seeing what you have, its going to be hit and miss, and I dont do hit
and miss well, since its about getting it fixed the first time, and that
requires being there.
I will offer this...chances are you have wired the stat wrong, and taken out
the transformer. Old letter designations on units are NOT what is used
today, and many cheaper thermostats, like Lux, Hunter and those China made
units at Home Depot use letters that DO NOT match up with the wiring of old,
and the end result is that you burn up a transformer, or board. You COULD
still have burned out the board in the outdoor unit, rather, the YorkGuard
Module that is used in those units, and if you did, the retail price is
$455.14....those units are some of the more expensive ones out there to
replace...and even require a special York supplied scan tool to properly
work on the unit...
At this point, you can do one of two things, since you state that the old
stat wont work either.
1- Stop now, and call a tech out to find out what you did wrong, and repair
2- you can see if you have 24VAC on the R and C line. If you do, then you
have something wired wrong. The trick is, no one here can see what is wired
where, and that requires option #1..unless you are familiar with the wiring.
As help, but with not a guarantee in the world that your unit is wired
correctly, and with the hydronics unit wired in with it, all bets are off as
to how it could be wired, but if you have 24VAC at the R and C, you need to
insure that you have your O, Y, W1, W2 and G wires in the correct locations
and you need to insure that the X that you have or stated you have, isnt the
feedback loop off the outdoor unit....if it is, and you wired it like a C,
you are out at least $400 for the new module. The YorkGuard uses letter
designations that are the same, to a point, but add several that do other
things that no one elses does.
I suggest that if you have to call in a tech, that you go to Yorks website,
and use the dealer locator to find a company that can work on your unit
correctly, as we get called all the time by others because we have the tools
and scantools for that module...sounds like you might need that.
No problem, but remember what I said about that YorkGuard module. Its been
superceeded a couple of times and the new one is NOT cheap.
Also, if the unit you have has LEDs on it, if they are glowing dim....thats
There is no module in the airhandler, it is outside in the unit you have
The airhandler will, or should, unless its been moved to the hydronics unit,
a transformer..thats your thermostat power....
The YorkGuard module outdoors in the unit will have the LEDs, and something
as simple as one wrong wire, can kill it...
Thanks for your helpful advice. Turns out it was just the transformer
in the blower unit, as you expected. We replaced that, reset the fault
in the heat pump, and all is now well. Total cost of repairs was $14,
and a few hours of my dad's time.
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