Heating Help

Problem connecting PTAC to remote thermostat

Still working on this PTAC in our addition:

I'm trying to improve a marginal situation by operating an older PTAC
with a remote thermostat rather than the unit's poor built-in controls.
Little direction is available from Amana (Goodman) or the manufacturers
of the two thermostats I've tried. Previously I had connected an old
Honeywell T87F (round, mercury) t-stat that I'd removed from another
location. It worked in cooling mode but not heat; it could not energize
the fan circuit in heating mode. Rather than rig up something with a
relay I decided to just grab a cheap modern t-stat that should work with
the PTAC.

Here's what I need to connect:

-Amana PTC093A35AB PTAC; single stage cool, single stage electric heat (no heat pump)

-LuxPro PSD011W thermostat

The wiring diagram for the PTAC is on page 17 here: http://becketthvac.com/manuals/Amana/PTAC/service.pdf

The diagram from the t-stat is page 2 here: http://www.luxproproducts.com/pdfs/P...G_Manual53.pdf

Here's how I connected these:

PTAC -->T-stat

GH =G
Y/W1 =Y
W2 =W1
R =R
C =C

But it didn't work. There is power to the t-stat, the fan will operate
manually, but the PTAC does not respond to a call for heat or cooling.
The idiot light on the control board signals either OK or thermocouple
error. I should note that I've tried this with J2 on the T-stat set to
"electric" and "gas" but neither work.

Any thoughts on how to proceed? I called Amana, who sent me to Goodman,
who left me on hold for 25 minutes. Haven't tried Lux yet, based on m experience with Honeywell they'll just send me back to Goodman.

thanks,
Kiwanda

cesar hvac

first need to add a jumper between RH and RC in the stat,and set the stat to electric heat on a call for heat the fan will run and the electric heat.

» Problem connecting PTAC to remote thermostat

It came with a jumper installed between RH and RC. Tried it with that jumped and set to electric. No dice.

Thoughts? Should I check for voltage across Y and W with calls for heat/cooling to make sure the stat is working?  The control board on the PTAC flashes a "normal" code when not set to the remote stat, so I assume it's OK.

-kiwanda

check voltage

I would definately check voltage across the thermostat.  See if on a call for cooling and heat you get 24v to C  across Y and W.  If you are not getting voltage then the thermosat is not working.

PTAC

Did you put the "t'stat/remote switch " in the remote position ?

Got it working, thanks!

Checked the fuse, jumpers, and all connections and finally got this working last night. While troubleshooting the setup I
must have fixed a bad connection; when I reconnected it all after testing the t-stat it worked.



I think the problem was likely the silly design of the main board on the
PTAC. Rather than a terminal strip it just has 14 pins coming off the
board. There's a little plastic housing that slips over the pins, and
you must insert jumper wires with spring clips into the slots for the
appropriate connections. I removed and reinstalled those after checking
the everything and it magically worked.



I appreciate the help with this. After failing with the old Honeywell
unit I was sure this new Lux would work fine. Glad it eventually did;
it's already evident that having a real t-stat controlling this unit is
far better than the primitive dial control it was delivered with. As a result I'm going to keep it for a winter (we see -25F here) and see just how much it will cost to heat the guest suite electrically before I decide whether or not to invest in a gas replacement.



regards,



kiwanda