O.T.~ Thermostat wiring for cooling

Trying to salvage a good little GE 5,000 window AC unit. Didn't have any luck finding a new one of the mechanical thermostats to replace this one with burnt contacts. The unit cools like a new one.. but wouldn't cycle on and off.

So, I removed the built in mechanical (bulb type) temp control thermostat.

In it's place, I put in a little hvac relay with a 24vac coil.

The 2 wires that went to the temp control.. I attached them to the N/O contacts on the relay.
I have a little 24vac transformer to power this relay. Connect the 24v to the relay, and the unit starts cooling... now, I just need to figure out how to operate it via this external thermostat.

I bought a Honeywell CT87N thermostat (heating/coooling) ... which I mistakenly hoped was all mechanical inside.... to control the system.




To make a long story short... it's not mechanical, but "electronic"... I guess you'd say.

The thermostat has 7 terminal screws... I put up a drawing from the instructions.

This, being a "hybrid" system... only has two wires.

All I need this new thermostat to do is actuate the coil in the relay to power up the compressor to start and stop cooling.

I can't wrap my head around how or where the wires go on this Honeywell tstat.

I've watched some youtube vids.. but nothing quite like what I'm doing on there.

I'm usually pretty good at figuring out stuff like this.. but being in a rush cobbling stuff together to cool things off.. I can't figure it out.

Just need to know the letter codes...

Honeywell is making more money in security systems and can't be bothered to explain hvac letter codes.

Thermostat Wiring Colors Code | HVAC Control

One side of transformer 24v output to one side of relay coil and C terminal of thermostat if it has one. Other side of transformer 24v output to RC/RH terminals on thermostat. Y terminal on thermostat to other side of coil on relay. R(RC) terminal closes to Y terminal on a call for cooling. R (sometimes called RC) and RH are usually left jumpered unless separate units are used for heating and cooling. RH makes to W on a call for heating (not needed for this). C terminal and RH or RC provide power to the stat IF IT IS A SYSTEM POWERED STAT (NOT BATTERY) OR IT IS NOT A POWER STEALING STAT.

JR

That sounds promising.... when I get off work I'll get on it.
Thanks for the response.

Jlrii...

It worked.

AC in there cycling on and off like it's supposed to.

Thanks a lot...