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  • No A/C :(

    No A/C in my house today.

    Specs I know of:

    Older Comfortmaker 9.0 SEER with gas heat.
    White Rodgers digital thermostat.

    I removed the batteries for the heck of it (electronics and all ), reinstalled them, I heard the thermostat click and the A/C start and immediately shutdown.

    Thanks for any input.

    J.C.

  • #2
    Re: No A/C

    did you reinstall the same batteries? have you tried new batteries?


    if you can open the furnace try jumping the R terminal (24v transformer) and Y (compressor contactor) and see if it power on the system (inside and out) if it does then it most likely is your batteries, this is assuming you have a furnace with a circuit board on it


    if you do got a board and your stat has a C terminal (common) on it you can fish a wire to have constant power to the stat

    Comment


    • #3
      Re: No A/C

      JC what are you calling your A/C when you say "The AC kicked on"?

      The Indoor blower came on?

      and /or

      The Outdoor Unit (condenser) came on? ( Fan or Fan and Compressor?)

      More info and I'll get ya through it


      A/C troubles in order for my area

      -Dirty Condenser causing High Head either cycles compressor on internals or causes head pressure to spike reducing system capacity

      - Bad Capacitor causing compressor to cut out on internals at call for cooling. ( Always use 440V capacitors if you can, 370 Sux)

      - Restricted Indoor airflow (Clogged Filter, blocked return, clogged evaporator coil, dirty blower) causing system freeze-up.

      - Dog chews the T-Stat wire ( cooks 24V transformer on older systems or blows 3amp control fuse on blower board in newer systems)


      - Ants in Contact points or blown out points.

      - Anything made by Janitrol / Goodman

      Comment


      • #4
        Re: No A/C

        Originally posted by OkieBill View Post

        - Bad Capacitor causing compressor to cut out on internals at call for cooling. ( Always use 440V capacitors if you can, 370 Sux)
        You know it. Actually if you were to read the peak-peak (Using a special Volt meter or oscilloscope) Voltage it's no wonder the 370 Volt running capacitors have short lives. Get the same MFD rating in a 440 Volt and somehow make it work. Strap mount it and rig up your own wiring if you have to. As long as it's inside the case where children can't get to it you should be OK. Be sure the connections can't short to the case or it's time

        Comment


        • #5
          Re: No A/C

          Originally posted by OkieBill View Post
          JC what are you calling your A/C when you say "The AC kicked on"?

          The Indoor blower came on?

          and /or

          The Outdoor Unit (condenser) came on? ( Fan or Fan and Compressor?)

          More info and I'll get ya through it


          A/C troubles in order for my area

          -Dirty Condenser causing High Head either cycles compressor on internals or causes head pressure to spike reducing system capacity

          - Bad Capacitor causing compressor to cut out on internals at call for cooling. ( Always use 440V capacitors if you can, 370 Sux)

          - Restricted Indoor airflow (Clogged Filter, blocked return, clogged evaporator coil, dirty blower) causing system freeze-up.

          - Dog chews the T-Stat wire ( cooks 24V transformer on older systems or blows 3amp control fuse on blower board in newer systems)


          - Ants in Contact points or blown out points.

          - Anything made by Janitrol / Goodman
          Thanks for the info/reply.

          If I set the stat fan control to on, the fan blows fine.

          If I put in the normal cool setting, the outdoor unit comes on for maybe 1 second, then shuts down. You can duplicate this every time with the exact same behavior.

          Almost like a short that protects itself and shuts it down.

          I azz-u-me it's not frozen. Same results about 3 hours later.

          Indoor airflow should be ok. I clean the filter regularly and vacuumed the ducts as much as possible about 6 months ago.

          I also keep the outside fins washed down regularly. Good or bad?

          And I take covers off about once a year and just make sure things are clear of webs, critters, and leaves.

          From your list, I steer towards capacitor.

          Thanks again.

          J.C.

          Comment


          • #6
            Re: No A/C

            I'm leaning toward a bad combination Capacitor (one cap used for both the Compressor and the Condenser fan motor)...

            Unless Comfortmaker has an auto reseting low pressure switch. (Most times a head pressure switch is a manual reset and a low pressure switch is auto reseting...) If you have a system leak a LP switch could be your problem as well...

            Bill

            Comment


            • #7
              Re: No A/C

              Thanks Bill.

              I think I'll call one of the local A/C boys as I can't remember how to discharge a capacitor.

              J.C.

              Comment


              • #8
                Re: No A/C

                Originally posted by JCsPlumbing View Post
                Thanks Bill.

                I think I'll call one of the local A/C boys as I can't remember how to discharge a capacitor.

                J.C.
                lick your fingers then...wait never mind, you won't like that at all.
                ---------------
                Light is faster than sound. That's why some people seem really bright until you hear them speak.
                ---------------
                “If I had my life to live over again, I'd be a plumber.” - Albert Einstein
                ---------
                "Its a table saw.... Do you know where your fingers are?"
                ---------
                sigpic http://www.helmetstohardhats.com/

                Comment


                • #9
                  Re: No A/C

                  Originally posted by JCsPlumbing View Post
                  Thanks Bill.

                  I think I'll call one of the local A/C boys as I can't remember how to discharge a capacitor.

                  J.C.
                  50 Watt 250 Volt light bulb in test socket that has two short wires coming of it. Carefully connect it across the capacitor and leave about a minute. Just be sure you are not part of the circuit.

                  For the brave you use an old screwdriver and short the connections on the capacitor. Eye protection is mandatory if you do it this way.

                  It's best you call in a good HVAC Tech.


                  Bob D. - Let the fun times roll. Zappa LOL

                  Comment


                  • #10
                    Re: No A/C

                    Fixed it. Thanks.

                    J.C.

                    Comment


                    • #11
                      Re: No A/C

                      So what was it?

                      Comment


                      • #12
                        Re: No A/C

                        Originally posted by plumberscrack View Post
                        So what was it?
                        Sorry. I found a mass of thick cobwebs/dust/lint/whatever at the large capacitor connections. I discharged it and cleaned it up thinking it was shorting at startup. Then cleaned everything else up some for the service person I was going to call. Had the phone in my hand when I switched the thermostat on.

                        And....it came on. I think it was luck.

                        J.C.

                        Comment


                        • #13
                          Re: No A/C

                          Oh, ok so you didn't really 'fix' anything

                          Comment


                          • #14
                            Re: No A/C

                            Originally posted by JCsPlumbing View Post
                            Sorry. I found a mass of thick cobwebs/dust/lint/whatever at the large capacitor connections. I discharged it and cleaned it up thinking it was shorting at startup. Then cleaned everything else up some for the service person I was going to call. Had the phone in my hand when I switched the thermostat on.

                            And....it came on. I think it was luck.

                            J.C.
                            J. C.

                            You would not believe what insects can do to electrical equipment when they just want a new home. I'm glad it's working again for you. Keep cleaning up any little messes you may find.

                            Comment


                            • #15
                              Re: No A/C

                              fyi, run capacitors don't hold a charge. No need to discharge them. A start cap does and boy does it but almost always have a resistor across it so a few seconds after power off, it's safe.

                              Another possibility for that type of issue (near me) is a 10 min on delay that the electric company installs at the disconnest. If the board in IT is bad, they come on for a sec and don't come back on.

                              Loose terminals at the cap could have been the cause but after you heard it come on and back off, did you hear it buzz or groan every min or so? If so you have a FAILING cap.

                              Good you didn't have to pay though, yet. My advice, buy a cap online and install it preventively. Do the contactor too!
                              Be sure 240 and 24vac is off though

                              Comment

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