I have to trip the AC relay to get compressor to kick in

[IHalterman]

Hello,

I tried to search and find an answer to this, but couldn't find anything.

Here is the issue. My roof top AC compressor won't start unless I manualy trip the relay.


When I adjust the thermostat it will kick out, but won't kick back in. If I have the unit turned off and trip this relay then turn it on, it kicks in. I don't know if maybe a capasitor would cause this. Im not realy sure what the name of this relay is. I can't match it to the wireing diagram.



I think it is the T.D. Relay that is shown as optional. If it's optional, could I get rid of it?

Many thanks in advance.

[IHalterman]

By the way, this is a Duo-Therm Rotary Sunchaser

[Gary RVRoamer]

Sounds to me like the relay is weak. The solenoid can hold it in place once you manually engage it, but isn't strong enough to pull it in by itself. Why not just replace the relay? Assuming you can find one, that is.

The time delay is to prevent the compressor from restarting immediately after it shuts off, as might happen if there is an electrical flicker or somebody bumps the thermostat up and back down quickly. Head pressure is too high to restart immediately - it has to wait about 2 minutes before re-starting. I'm told damage can occur if you don't wait, so the time-delay prevents that.

[wa8yxm]

Can you get rid of a Time Delay Relay.. YES..... HOWEVER

YOu may still need a relay at that location (The T-stat at most is switching 24vac, the relay may pass on a 24 volt switch after time delay or it may toggle 120vac.. The T-State, if hooked to the 120 volt side of a relay, would go in a bright flash and smoke.

IT's there for a reason.. And for that reason I"d replace it if it's bad, not get rid of it.


The reason is this... I have had power go off and back on quickly.... Once it goes off, an air conditioner compressor should STAY OFF for a minimum of 3 minutes, more or less depending on model.
The reason

[RV Wizard]

The relay in the picture is the time delay relay according to the schematic. If you are comfortable with putting any money into this unit (it is old and could fail), You will need to replace it as Gary has said or bypassed putting a strain on the compressor and starting circuit components. You might want to bight the bullet and upgrade to a new unit and not let this one nickle and dime you to death.