Old Bryant Split unit with R-500!!HELP

[AirComfortMecha]

I have this unit its a Bryant very old. The contactor was not pulling in for the comp and fan. I have 24v at the coil of the contactor but it does nothing. I ohm it out and its good push it in and comp and fan runs. Its the original contactor so I just replace it anyway. My next thought is the transformer Im thinking I may not have enought VA for everything in the system. It has a impendance relay(its wired in with the comp over load protection), comp contactor, and the fan relay. Would it uses a 40VA or more??

[d_griff]

I have this unit its a Bryant very old. The contactor was not pulling in for the comp and fan. I have 24v at the coil of the contactor but it does nothing. I ohm it out and its good push it in and comp and fan runs. Its the original contactor so I just replace it anyway. My next thought is the transformer Im thinking I may not have enought VA for everything in the system. It has a impendance relay(its wired in with the comp over load protection), comp contactor, and the fan relay. Would it uses a 40VA or more??

you may be losing your common somewhere..
did you replace the contacter or are you saying you are going to?

[bustawrench1]

Do you have 24V at one side of the coil to ground, or do you have 24V across the coil itself?

Sounds like a safety is open.

[heatingman]

I have this unit its a Bryant very old. The contactor was not pulling in for the comp and fan. I have 24v at the coil of the contactor but it does nothing. I ohm it out and its good push it in and comp and fan runs. Its the original contactor so I just replace it anyway. My next thought is the transformer Im thinking I may not have enought VA for everything in the system. It has a impendance relay(its wired in with the comp over load protection), comp contactor, and the fan relay. Would it uses a 40VA or more??

Test voltage one side of the coil to the other. Many times if you check between ground, and the coil you'll read 24v when you dont realy have it.

Low Va will cause reduced secondary volts under load.

[AirComfortMecha]

I did replace it and it still doesnt pull in. I took the connectors off the contactor and I had 24v but i didnt check to ground, I jumped my low and high pressure safeties and still nothing there both closed. The only thing Im puzzled about is that impendance relay. Maybe its that.

[clgman]

Some of the older Bryant (Carrier) units used external motor overloads with an over temp klixon type relay in the motor terminal box. The impedance relay, I believe is a lockout relay, so its coil will be shuntted out by the safety controls. Use a fused jumper (3to5 amp time delay fuse) and work your way around the control circuit. Unless you have very low control voltage or chattering relays you should not have to up the VA on the control transformer, it must have run at one time. Good luck.

[clgman]

Question ? Is there a mechanical timer on the unit - Jump Ato A1 if there is.

[AirComfortMecha]

Some of the older Bryant (Carrier) units used external motor overloads with an over temp klixon type relay in the motor terminal box. The impedance relay, I believe is a lockout relay, so its coil will be shuntted out by the safety controls. Use a fused jumper (3to5 amp time delay fuse) and work your way around the control circuit. Unless you have very low control voltage or chattering relays you should not have to up the VA on the control transformer, it must have run at one time. Good luck.

I dont get it? that impendance relay has no 24v to it. On the wiring diagram it shows that all its points only get the common side of trans ..the klixon is still good.. I guess Ill call Bryant to make sure thats the right trans and take it from there. I have to get that running tomorrow.

[AirComfortMecha]

Question ? Is there a mechanical timer on the unit - Jump Ato A1 if there is.

Nah no timer...

[d_griff]

I dont get it? that impendance relay has no 24v to it. On the wiring diagram it shows that all its points only get the common side of trans ..the klixon is still good.. I guess Ill call Bryant to make sure thats the right trans and take it from there. I have to get that running tomorrow.

you couldbe losing that 24 volt anywhere..im gonna guess it def. isnt the transformer VA..you are not getting your 24 volts back to common

[AirComfortMecha]

you couldbe losing that 24 volt anywhere..im gonna guess it def. isnt the transformer VA..you are not getting your 24 volts back to common

Okay.. im gonna make sure I check that common side tomorrow..

[clgman]

Just wondering if you resolved the issues with the unit ?

[AirComfortMecha]

Just wondering if you resolved the issues with the unit ?

Thanks guys I got that unit running that morining I went back. It was my common it was not returning to the trans. It was getting lost at the overload safeties after that impendance relay..