outside unit not working on split system

[spdrcr]

hello again, got my heat fixed and now i went to use the a/c and it doesnt work. im not sure what brand omy a/c unit is, the labels are faded. what i do know is i have a coleman furnace and a 2-wire relay box (nordyne).

i am fairly certain my contactor is bad. when i set the unit and thermostat to call for a/c the inside fan runs and the contactor spring-loaded contacts pull in, and i hear a slight humming from the outside unit (only when standing real close to it).

i guess my question is: how do i test it, i have a multimeter and jumper wires. my guess would be to check for power in, then power out if contactor, but im not 100% sure of which wires do what. i also wondered if my capacitor could be bad.

any help is appreciated.

here are some pics of the unit and contactor/capacitor

[Robert]

Hi,

Set t-stat to call for a/c = Cool-Auto-65*



At contactor, small yellow to left side and small black to right side.

Set meter to read 20 - 30 vac:

Place one meter lead on each at same time, should read 24-28VAC.


Be CAREFUL as there is LIVE 240VAC in there at contactor.



IF there, then go to bottom two brass screws.


Set meter to read 225 - 300 vac:


Black wire to left L1 and White wire to right L2.


One meter lead on each should read input of 240VAC




Then go to top big yellow wire on left T1 and big black wire on right

T2 = one lead on each should read output of 240VAC IF contacts pulled in ALL the way and HOLDING IN.




Let me know what ya get. Also, give me any p/n's on side of contactor.

Looking for a Volt Amp rating = 30VA or maybe 40VA.




Thanks,
Robert

[spdrcr]

ok, i have 24V power with the conditions above on the small black and small yellow.

i have 240V across the bottom screws, and i have no power across the top screws (big yellow and big black).

the contacts visibly pull in and cannot be moved when the 24V is energized, i took a stick to try to wiggle the spring-loaded contacts and they seem to be tight and making good contact.

does this mean the contactor is bad? if so, the numbers on the side of the sticker are faded away, how do i determine the correct replacement?

thanks again,
Jason

[Robert]

Hi Jason,

If you have 240vac input at bottom and with t-stat set to call for cooling, you have 24vac at sides, then you should have 240vac at top.


Contacts may be pulling in, but not making contact due to pitting.


Contactor # 621665 @ $16.50 + $6.75 shipping .


It can be seen and ordered through PayPal from right side here:


http://www.mobilehomerepair.com/NordyneAC.html


Or, by calling toll free after 9AM CST to 1-877-263-7860 and

charging to Visa or Mastercard.


Not knowing contactor p/n, have to go with largest VA used which is what I prefer to do on all units anyway.

This one also has a cover over contacts to help protect them somewhat.


Take care and best wishes,
Robert

[spdrcr]

FIXED!!! thanks again for your help and al that this board does.

i removed the contactor and viola! burned contacts. i removed teh contacts and cleaned them with an old tooth brush, re-assembled everything, and it works great now. i ohmed the side the contact switches before i cleaned them, the meter indicated open circuit, after i cleaned the contacts the meter showed 1.4 ohms.... should work good enough.

i think when i had the problem with the heat and the inside and outside unit were chattering thats what burned the contacts...

thanks again, ill order a contactor so when this one goes out i can replace it.

Thanks,
Jason

[Robert]

Hi Jason,

You're very welcome.


It has already gone out. Cleaning them is a non issue, they will just get pitted again over and over.


Once they have pitted, they're ruined.


IF they pitt enough to fuse together and not release, you can lose your compressor.


I would order or buy one as soon as possible and replace immediately upon getting it.


A lot of compressors have been lost due to exactly what you just did and a false sense of security.




Take care and best wishes,
Robert