Outside AC unit not turning on !

[whuggs1]

ok the 24 volt wires at the outdoor relay (1) has 24v (1) does not have anything. the one that has the 24v goes to a small circuit board. The wire with nothing coneccts with a big yellow wire and a tiny red(i'm gussing it goes to the circuit board inside on the blower / heater.

"Is this air that is on a furnace?" This is a split system with blower / heater inside and AC unit outside.


ok the TA has a C post but it's not used, The circuit board connections on the furnace/blower unit have a C with a small red wire and a big yellow wire. The yellow wire goes into the blend air box. The C doesn't have any volts, but the Y has 24V whe calling for cool.

[paul52446m]

Yes have the jumper from RC to R,(no RC) the reason we changed the stat was I read that if you connect the RC to the Y wire the ac should start(and it did) so the satat must be bad. Now i'm thinking maybe the old one is still good.

Today my wife said the ac had turned off and then it did restart with no problems. So seems like 10% of the time it works and 90% of the time not.

I was asked in a nother forum to remove both 24v wires to the contactor and then turn on the air,use a screw driver to push in the contactor and see if it will stay running. It just pops back out and turns off.


wayne

When you take off the 24 volt wires at the outdoor relay then with the stat calling for cooling you should test 24 volts on those two wires. Is this air that is on a furnace? If so when you are calling for cooling check post Y to C at the furnace and see if you have 24 volts? Also keep in mind that some of these thermostats and electronic boards have a least a 5 min. time delay built into them,
so it can be 5 to 10 min after you call for cooling before it comes on. Paul

[whuggs1]

Yes have the jumper from RC to R,(no RC) the reason we changed the stat was I read that if you connect the RC to the Y wire the ac should start(and it did) so the satat must be bad. Now i'm thinking maybe the old one is still good.

Today my wife said the ac had turned off and then it did restart with no problems. So seems like 10% of the time it works and 90% of the time not.

I was asked in a nother forum to remove both 24v wires to the contactor and then turn on the air,use a screw driver to push in the contactor and see if it will stay running. It just pops back out and turns off.


wayne

[paul52446m]

Outside ac unit not starting. I don't have 24V on the side wires to contactor(not sure if I’m checking it correctly). So far replaced contactor, cap, and thermostat. If RC wire and Y wire are connected from ta it will start. I can also pull one of the 24v wires off the contactor and it will start as well. This morning I went out to pull the wire from the contactor to start the ac and decided to look at the little circuit board and wiggled a resister on the board and it started.........help I’m going crazy.
Unit is a: NORDYNE SPLIT SYSTEM
Model S1BA - 048K

Please help

Ok you said you changed your stat. You have a RH and RC post in your stat.
You need to have a jumper between these two post. Do that first and see what happens. Paul

[whuggs1]

Outside ac unit not starting. I don't have 24V on the side wires to contactor(not sure if I’m checking it correctly). So far replaced contactor, cap, and thermostat. If RC wire and Y wire are connected from ta it will start. I can also pull one of the 24v wires off the contactor and it will start as well. This morning I went out to pull the wire from the contactor to start the ac and decided to look at the little circuit board and wiggled a resister on the board and it started.........help I’m going crazy.
Unit is a: NORDYNE SPLIT SYSTEM
Model S1BA - 048K

Please help