Replaced themostat with same style. Still no 25v AC to outside unit. Contactor does not pull in, transformer is very hot. RC and RH terminals are jumpered.

There is this guy that I am in love with I want to know if he feel the same way about me

Sounds like love is in the air with the previous poster. What type of system(heatpump or gas furnace) what make of system(Rheem, Carrier,Trane,Lennox) And the most important question is how did the old thermostat wire up?

tixie, just ask him, or post your question under relationships.



Car, please answer t-tops questions and we will try to help.

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Originally Posted by car9172

Replaced themostat with same style. Still no 25v AC to outside unit. Contactor does not pull in, transformer is very hot. RC and RH terminals are jumpered.

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It is a Coleman SCS 2 used in mobile homes. Unit worked fine earlier this year, thermostat smelled burned so I replaced it. I also jumpered the wires to send 25v to outside unit, contactor did not close.

How and where did you jumper the wires. Try jumping them at the funace between r and y. let us know what you find. Also, if you have a volt meter, check to make sure there is not 24v at coil on contactor outside.

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Originally Posted by car9172

Replaced themostat with same style. Still no 25v AC to outside unit. Contactor does not pull in, transformer is very hot. RC and RH terminals are jumpered.

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I jumpered w and y at the thermostat. There is no voltage on the coil of the contactor. Not sure what you mean about furnace. Wires from thermostat-- one goes to coil the other goes through a transformer then to the other leg of coil. That trnsformer is very hot.

OK, you should be jumping r and y, instead of w and y. try this.

Quote:

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Originally Posted by car9172

Replaced themostat with same style. Still no 25v AC to outside unit. Contactor does not pull in, transformer is very hot. RC and RH terminals are jumpered.

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I have RC, RH, W , and Y. RC and RH are are jumpered at the terminals as per the thermostat instructions.

Go to the thermostat open the cover do you see a red wire and a yellow wire jump it that will start the unit outside. Red wire is your hot or 24 volts yellow is your cooling and green wire is your fan and white is your heating.. note one thing safey is frist... www888aizeoffilter.com

Some coleman units used a 3 wire setup and had a change over at the furnace, this may be your problem. What kind of t-stat was your old one?

Quote:

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Originally Posted by car9172

Replaced themostat with same style. Still no 25v AC to outside unit. Contactor does not pull in, transformer is very hot. RC and RH terminals are jumpered.

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This is a mobile home so wire colors are probably not normal. I have a what and red coming from transformer in furnace, and a what and red going to outside unit. Heating and cooling have separate fans.

You have two seprate units? Then the jumper needs removed.

Quote:

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Originally Posted by car9172

Replaced themostat with same style. Still no 25v AC to outside unit. Contactor does not pull in, transformer is very hot. RC and RH terminals are jumpered.

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The cheapest " Rite-Temp" they had at home depot

OK, no problem, if the ac and the furnace are 2 seprate blower then remove the jumper between rh and rc

Quote:

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Originally Posted by car9172

Replaced themostat with same style. Still no 25v AC to outside unit. Contactor does not pull in, transformer is very hot. RC and RH terminals are jumpered.

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I removed the jumper reinstalled the thermostat turned to cool still nothing

Then you may have triped a reset or blown the transformer on the ac unit. You have the furnace wired to rh and w and the ac wired to rc and y?

Yes that's correct. The jumper was in there with the previous thermostat which was the same as the new on

What is the purpose of the transformer in the ac unit before the contactor? By the way thanks for all the help.

To power the ac unit. So just so I am clear on what you have. You have a furnace inside? And a package unit out side with flex duct under the trailar to supply the air for ac?

Yes

Then I am not sure why the old t-stat had the jumper. The outdoor and the indoor will both have a transformer. That is why the one inside was getting hot you may have had double power on it.

The one on the outside was hot . I cut the wires from the thermostat where they came into the outside unit, I have my 24v at that point. I reconnected them and have 0v at the contactor coil. The only thing between those two points is that transformer. What's your opinion?

Did you cut the wires with the ac breaker on? If so you will probably need a new transformer

No , this started with a heavy thunderstorm. I heard a pop and went to the thermostat, it smelled burned and the AC hasn't worked since.

Ah OK. Yes it could have burnt the transformer when it burnt the t-stat

I'm going to price a new transformer. Thanks for all your help.

Hope this is your problem, please let us know how it turns out.