[pwcopy]

Outside compressor model CK36-10. 19-years in service.
Ser # 0006482183
Contactor Model B1360321

Hello all. For the second season in a row, I've had to futz around with the contactor to get the a/c unit going. I take it (until somebody on here corrects me) that it needs replacing.

I'm not an electrician or an HVAC guy, but I helped build my home 20 years ago (plumbing and electrical), installed the electrical for a NG direct-vent fireplace I added, and do a lot of fixing around here. Any project that requires permitting gets it, and they all pass inspection.

I know about shutting everything down (breaker off, remove bridge in junction box). What care do I need to take around the capacitor, which I'm guessing is the silver canister in the photo?

Many thanks for your help, PW

 

[user_12345a]

Normally the capacitor discharges itself through the motor windings but you can short the terminals with a screw-driver (with no power) to be sure.

proper way to discharge is with a high-resistance bleed resistor.

If your contactors are dying, there may be a reason - low quality parts, insects getting in, wrong amperage.

 

[pwcopy]

Normally the capacitor discharges itself through the motor windings but you can short the terminals with a screw-driver (with no power) to be sure.

proper way to discharge is with a high-resistance bleed resistor.

If your contactors are dying, there may be a reason - low quality parts, insects getting in, wrong amperage.

Thank u for the tips. This original contactor has spent 18 years of Michigan summers working and Michigan winters under an a/c unit cover (still pretty much out in the elements). Would that have anything to do with it?

 

[user_12345a]

oh I thought you changed the contactor last year and it's bad again.

 

[dj3]

From the OP I gather that in 19 years he went through 2 contactors - the original that lasted 18 yrs and the second one that lasted 1 yr.
Was the second contactor a matching replacement single, 2 or 3 pole? Who installed it?

 

[pwcopy]

From the OP I gather that in 19 years he went through 2 contactors - the original that lasted 18 yrs and the second one that lasted 1 yr.
Was the second contactor a matching replacement single, 2 or 3 pole? Who installed it?

Clarification: There has only been 1 contactor on the a/c unit. Last year I blew all the cobwebs and crud from under the shield that covers the parts you see in the photo, and shot some W/D40 on the contactor slider. After that it worked fine. This year, the same original 19-year old contactor is acting up again, and last year's cure doesn't seem to be working.

One more question: I've assumed that the problem is the contactor, but because I'm not an HVAC guy, I haven't tested it (don't know how). The only other component in the photo I sent, is the capacitor. Could that be bad? Could I test it without electrocuting myself?

Last nite I got it working and took the temp at a few vents around the house. The system was blowing 55ºF, so I think the compressor is OK. Compressor fan runs fine.

A/C Unit: Goodman CK36-1D

Contactor: B1360321 superseded by CON2P30A24V Goodman-Amana 2 Pole 30 Amp 24 Volt

Capacitor: B9457-7200 Janitrol Goodman Amana Dual Run Capacitor 45/5 uf MFD 370 Volt VAC

 

[user_12345a]

Buy a multi-meter if you don't have. Get one that can check capacitance - the cost is less than a service call if you get one of the cheaper ones, suitable for casual use.

I'll tell you what to check.

Changing out parts without diagnosing is never a good idea.

 

[pwcopy]

This is the multimeter I own:
The Cen-Tech - 92020 features a max current of 0A AC and 0.00001A DC and a max voltage of 750V AC and 0.001V DC. The multimeter has a max resistance of 2. and can measure capacitance.

The description says it can measure capacitance, but I don't see the right symbol, –|(– , on the control layout.

 

[pwcopy]

Buy a multi-meter if you don't have. Get one that can check capacitance - the cost is less than a service call if you get one of the cheaper ones, suitable for casual use.

I'll tell you what to check.

Changing out parts without diagnosing is never a good idea.

See my post before this one for the meter I own now. Here's one from Harbor Freight that tests capacitance, but how do I hook up the tin can in my a/c unit to the socket on the multimeter control panel?

Many thanks for your help, PW

 

[user_12345a]

That meter is for testing small capacitors, would have to use rigid bare metal (inserted into the socket) and alligator clip wires to test the capacitor.

There are better meters than that available.

Don't worry about capacitance now, use what you have.

Be careful as the testing is done live, if you're not comfortable don't do it.

See if the contactor is getting line voltage coming in - set to ac volts, 750, check bottom of contactor.

If you are, turn on the a/c and see if the contractor pulls in.

If it pulls in, check for voltage on the outlet of the contactor - if you get nothing or there's a major voltage difference, change the contactor.

If you get voltage there, the problem is elsewhere.

If it doesn't pull in, check for 24v ac +/- on the low voltage connections. (thinner purple wires connected) For this part, the disconnect can be pulled/turned off.

If you have nothing there or it's far lower than 24v, the problem is on the low voltage circuit.

If you have proper voltage there, change the contactor.

Don't check in reference to ground, put both leads on what you're testing.

 

[pwcopy]

Be careful as the testing is done live, if you're not comfortable don't do it.

See if the contactor is getting line voltage coming in - set to ac volts, 750, check bottom of contactor.

If you are, turn on the a/c and see if the contractor pulls in.

If it pulls in, check for voltage on the outlet of the contactor - if you get nothing or there's a major voltage difference, change the contactor.

If you get voltage there, the problem is elsewhere.

If it doesn't pull in, check for 24v ac +/- on the low voltage connections. (thinner purple wires connected) For this part, the disconnect can be pulled/turned off.

If you have nothing there or it's far lower than 24v, the problem is on the low voltage circuit.

If you have proper voltage there, change the contactor.

Don't check in reference to ground, put both leads on what you're testing.

A little nervous, but was very careful.

Incoming voltage: Meter flips between 239 - 240.

Contactor pulled in.

Outlet voltage: Meter flips between 237 - 238. What is a major difference?

Turned off the breaker in the main panel. There are two purple wires, one each connected to a blade on opposite sides of the contactor. What do I touch the meter leads to on the contactor to test 24V power?

 

[user_12345a]

Your contactor isn't the primary problem assuming you tested at the right points - the two screws at the top of the contactor.

The drop across it could be from having high current being drawn by compressor/fan trying to start, and or contacts going bad*.

*Either way, voltage drop is not bad enough to prevent starting.

Shut the power and check all the connections.

If all looks good, will have to check capacitor.

 

[pwcopy]

Your contactor isn't the primary problem assuming you tested at the right points - the two screws at the top of the contactor.

The drop across it could be from having high current being drawn by compressor/fan trying to start, and or contacts going bad*.

*Either way, voltage drop is not bad enough to prevent starting.

Shut the power and check all the connections.

If all looks good, will have to check capacitor.

I'll work on it after I'm done at my day job, and get back to u later. (I played hookey to get this far.) I'm on U.S. eastern daylight time.

Thank u, sir