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Thread: CELLAR COOLER

  1. #1
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    I foolishly went to have a look at a searle cellar cooler today, with flu. I feel quite bad-sitting up in bed now.

    Problem is this. Unit tries to start, and cuts out. The guy said that the evaporator had iced up a couple of times over the last day or so, so I thought it must be low on gas, connected the gages and got 100 psi standing pressure. I noticed that the compressor runs on R404A, but the evaporator plate shows the mediums as R12, R22, or R502.So to start with I think someone changed the condenser rig wrong.

    As soon as the compressor tries to start, the contactors in the control board click back out, and the compressor stops almost instantly along with the condenser fans. I disconnected the lives from the compressor electric box. The main circuit breaker will stay on, but the contactors will not pull in-as theres no load.

    I tested the compressor and found the motor was good, so I think the problem is the start capacitor, but by then I was getting quite ill, and quckly discharged the start capacitor, and but a resistance meter on. The display graph rises to 14.6-on the 80kohms range I think and stays there, instead of going to infinity, but I had to get home quick and go to bed, so I hadn't stayed there that long, but the fact that the brewaker trips stright away makes me think it's the capacitor.

    Just a little story I wanted to share with you. There must be a moral to it, because if I had been well, I'd have sorted out. It's amazing how illness affects you, and how foolish it was to mess with the rig while unwell.

    Anyway. If anyone has any second opinions, then please reply.

    Regards
    James

    A problem shared is a problem halved

  2. #2
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    Sorry to hear you don't feel well and hope you get back on your feet soon. I read your post but a few things need tweeking.


    connected the gages and got 100 psi standing pressure
    If 404 that would be about a 48* basement, 502 a few * higher assuming that the unit has been off for a while

    As soon as the compressor tries to start, the contactors in the control board click back out
    but the fact that the brewaker trips stright away makes me think it's the capacitor.
    I am not clear about his. Did the breaker trip right after the contactors in the control board clicked back out? You may mean your breaker for contactor but I don't think so. Does your unit have a soid state control board with relays and/or a separate contactor for the compressor load?

    but the contactors will not pull in-as theres no load
    Here it is again. The contactor will/should pull in if the control devices are working properly. You said the compressor motor tested good but did you check the terminals to ground?

    404 will work on a 502 metering device. Do you have a cap tester to check the start capacitor?

    My first impression is since the evap has frozen up over the past few days that liquid slugging back to the compressor may have caused internal damage to the motor windings resulting in a ground out.

    Sorry about being confused here.





  3. #3
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    any coil that will work with R502 will work with R404A

    contacts that open as you said means that control circuit power turned off. Did it trip on Overload or what?

    If an overload trip, get winding resistance and check

    get over the flu and ask more fluent questions

  4. #4
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    Confused

    OK Feeling much better today.

    Ambient temp was 19 degrees in cellar and 17 outside. Looked on my comparator and saturation at this for 404 would give gage pressure 135psi.

    The compressor is not grounded I checked, and the resistance over the windings is OK. The rig has a receiver, so I know the charege isn't critical.

    When the power is switched on, the contactors in the control box pull in and then immediately trip back out along with the main RCD on the control box. At the condenser, the compressor and the condenser fans try to start, but immediately stop again.

    The start capacitor when my capacitor meter is connected shows 0 microfarads, and when the resistance meter is connected, instead of the needle swinging quickly towards 0 and then coming back towards infinity. It just rises towards 14 x 800 K Ohms (at least I think that was the scale I used) so I think that the capacitor cannot take the charge.

    Also forgot to mention that the rig has been running for about 2 years, and the ice only happened once the day before yesterday-so the guy says

    Rocket I see what you say about the cap tube working with 502, but the oil is different and the pipework don't look like it's been changed.

    Best Wishes
    James

    [Edited by bunglebear on 07-03-2004 at 07:04 AM]
    A problem shared is a problem halved

  5. #5
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    They haven't made a 502 system in some time. Check your compressor data for oil type. If it was 502 then your refrigerant should be 408a. There is an oil compatibility issue using 404a. Since there is a receiver then you have a TXP, there is no oil or refrigerant type issue with your metering devices.

    Your ambient temps must be in Celsius; sorry I am in the states. (F)

    If you isolate your compressor wiring (including all start components) from the load side of the contactor and turn on power does your contactor hold in? If it doesn't your problem is not with the compressor or start components as you well know.

    I would look at your on-board circuit breaker. It maybe weak and can’t handle the starting amps. Do you have proper voltage? Check amps and voltage reading during start up.

    Glad you are feeling better.

  6. #6
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    Question

    Hi Lusker

    Yes I,m in celsius. Funny thing is all my gages are in F, because I buy them from a place in Waco TX when I'm out there, because the company I work for is in the US.

    I disconnected the live feeds from the electrics box on the compressor, put the power on. It doesn't trip and it stays on, but the contactors don't pull in at all. When the contactors are pushed in there is continuity over the feed and load sides.

    Strangely for a 230V set up, I was reading 182volts on the feed.

    Best Wishes

    James
    A problem shared is a problem halved

  7. #7
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    Cool!... or should I say Not cool?

    Never been to the UK, family has and says it nice.

    I disconnected the live feeds from the electrics box on the compressor, put the power on. It doesn't trip and it stays on, but the contactors don't pull in at all. When the contactors are pushed in there is continuity over the feed and load sides.

    Strangely for a 230V set up, I was reading 182volts on the feed.

    You should only have 10% voltage variation. You are 20 volts below that minimum range. I would bet that is where your problem lies. Incorrect voltage. Lower the voltage=higher amps too. The longer your compressor hangs in start the on-board breaker takes a bigger load and kicks. As for the contactor not pulling in with the compressor leads disconnected makes me think you may have another problem in the controls or control wiring.

    Possible?

    After you isolate the heavy load (the compressor) all of the other control components should bring in the contactor. My stumbling block here is that you say with the compressor wired in everything comes on and kicks the breaker. Is it possible that when disconnecting the compressor you may also be removing an operational control wire?




  8. #8
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    Hi

    The UK ? Well it has it's good and bad points. The bad point is probably the weather, wet winters and warm summers. At the moment there's political problems with the Iraq problems, and particularly immigration, which is causing not only the UK but most of Europe to be swept by a wave of nationalism. I will be staying here for another two years or so, and then probably moving out to our corporate headquarters in Texas. Right now I'm not here that much anyway.

    The other thing is that the voltage is fine at the feed to the control panel, but is too low at the isolator outdoors 182V, so the incoming power isn't the problem. I should never have gone there unwell, because now I shall have to go back and look stupid !!!!

    The entire electrics, capacitors and everything else were isolated to get the power staying on. At the control box the voltage is good, but too low at the condenser.
    A problem shared is a problem halved

  9. #9
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    Don't dispare, when you go back they will see that you are feeling much better and will understand. If not, a good monkey wrench upside their head will help!

    The power to the isolator is where you will find your problem; one would think. Start there and work your way back. Check the basic stuff and start fresh and clean up. If you think the cap is bad, take one with you. Even an all-in-one hard start kit that will replace the potential relay will go a long way but you need to get the voltages right first.

    I don't think you have a refrigerant compatibility problem because it has been running for a few years. Ask them if another tech has been there with leak problems. Smart guys label their systems, smarta** will reap what they sew.

    Keep me posted, I would like a follow up.

  10. #10
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    lusker

    i have to go out now, so will be in touch in next couple of days
    A problem shared is a problem halved

  11. #11
    Join Date
    Jun 2004
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    Post low voltage

    hi, i think it is the low voltage causing the problem the motor cant get out of start windings i have had this happen too me also and caused a nwe unit too burn up just my thought also the contacter should pull in without a load on it contater is probly fed from line side . ken

  12. #12
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    Talking

    Hi Lusker

    Here's an update for you.

    Went back today-didn't need the monkey wrench. Started all over again feeling well. Disconnected compressor and powered up. I put the original start cap back on cos I decided that I had probably got it wrong so to prove I had put my analog meter on it, and the needle quickly zeros and then rises back towards infinity so the cap was good.With just the compressor isolated the power stays on, but the contactor don't pull in so I had to give it a helping hand with the screwdriver to see if it would trip or not. It went nuts and starting pulling in and out real quick I'd say 2 or 3 times a secoond. So I cut the power again, and restarted it. This time the contactor pulled in and stayed in the evap fans ran, and the condenser fans were running. So I decided I'd better see if the compressor was good. Resistance was exactly right, and it wasn't grounded. So I reconnected it. This time the whole thing ran compressor and all, but the contactors were cycling it off quite erratically. It wasn't on LP or HP and there is no real reason for the fact that it runs for a while, cuts out and then starts up, but it's maintaining the cellar at an acceptable level to them. The best thing would be to change the cooler as it's so old, but they are moving on in a couple of weeks and won't spend the money-so I've left it with them to call me if they change their minds.

    Thanks for your input also Ken.

    Best Wishes

    James

    PS If either of you have a definitive explanation for the conatactor cycling let me know. It isn't pressure, temperature etc, unless the contactor is going bad and starting to fail.
    A problem shared is a problem halved

  13. #13
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    James

    Now my curiosity is going crazy. It has to be either a coil going bad on the contactor or a voltage problem to the contactor coil.

    My two bits would be on a control causing a voltage drop or a skinned wire somewhere on the control system. I have also seen contactor jumping due to coil component corrosion.

    What voltage is the control system to the contactor?


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