| [GMCnet] AC Start Relay Replacement [message #66027] |
Sun, 29 November 2009 22:31  |
Oldrvguybcg
Messages: 100
Registered: September 2008
Karma: 0
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Senior Member |
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To All - I think my Start Relay is gone on my AC Roof Unit. I changed the
Start Capacitor a few months ago and since then it did start once but now
just grumbles. I pulled the relay while closing up my rig for the winter. I'm
looking for a cross to this Essex/RBM 128116-1645SD. If anyone has any
suggestions or sources for a replacement, please pass them along. Contact my
offline and I'll send you the photos or the existing relay.
Thanks,
Brian Gleissner
74 Sequoia
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| Re: [GMCnet] AC Start Relay Replacement [message #66073 is a reply to message #66046] |
Mon, 30 November 2009 08:58  |
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Matt Colie
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
Karma: 7
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Senior Member |
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| Oldrvguybcg wrote on Mon, 30 November 2009 07:08 |
Thanks Gene, I've seen that write-up. My unit must be original because the company went out of business in 1978 and I have a 1974 coach but it does not have the time delay. Does anyone know much about these "Hard Start" kits they are selling these days? It sounds to me like they are a Start Capacitor, Solid-State Relay, and maybe a Time Delay.
Regards,
Brian Gleissner
74 Sequoia
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Brian,
I use "hard start" kits lots of places they were not intended. Guessing by the recent change in Grainger's catalog, I'm not alone.
All they are is a package that contains a big capacitor and a thermistor. The thermistor is both the relay and the time delay. It heats up with the current load and takes the extra C out of the circuit.
Good Luck
Matt
Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
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| Re: [GMCnet] AC Start Relay Replacement [message #66146 is a reply to message #66046] |
Mon, 30 November 2009 17:02 |
roy1
Messages: 2126
Registered: July 2004
Location: Minden nevada
Karma: 6
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Senior Member |
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If you can't find the correct start relay a hard start kit should do the trick . It is not quite as good as the exact start relay and matching capacitor but should get the job done. Don't forget to disconnect the original relay and capacitor when you install it.
Roy
Roy Keen
Minden,NV
76 X Glenbrook
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| Re: [GMCnet] AC Start Relay Replacement [message #66175 is a reply to message #66027] |
Mon, 30 November 2009 19:18 |
Erv Troyer
Messages: 125
Registered: February 2004
Location: Lagrange, IN
Karma: 0
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Senior Member |
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Brian Gleissner wrote:
To All - I think my Start Relay is gone on my AC Roof Unit. I changed the Start Capacitor a few months ago and since then it did start once but now just grumbles. I pulled the relay while closing up my rig for the winter. I'm looking for a cross to this Essex/RBM 128116-1645SD. If anyone has any suggestions or sources for a replacement, please pass them along. Contact my
offline and I'll send you the photos or the existing relay.
+++++++++++++++++++++++++++++++++++++++++++++++
I was a Service Engineer for Duo-Therm during the time these coaches were built, so I am familiar with the air conditioners. There are two relays used in the compressor circuit; one is the time delay relay which delays the compressor startup for two minutes after the thermostat closes, and the other is the start relay that is used to remove the start capacitor from the circuit after the compressor is running.
I'm not sure which one you are looking for, but if my memory is correct, that is the number for the start relay, and not the time delay relay. The start relay has normally-closed contacts, and if that relay fails it will cause the start capacitor (the black one) to stay in the circuit too long, and will cause the capacitor to blow up.
Replacement relays should be available from air conditioning service companies, but the easiest replacement would be the thermistor type of hard-start kit that Matt Colie mentioned.
However, I think you might have a more serious problem. The compressor is designed to start with just a run capacitor (the gray metal case) if the supply voltage is correct. The other relays and capacitor were added because the supply voltage was often marginal at campgrounds back then. You said your unit "just grumbles" which may indicate a locked compressor. If you are able to verify that the voltage at the a/c is at least ~105 volts then I would guess you have a compressor problem, but further checks are needed to make sure.
If I was close to you I could help you check it out, but you haven't given us any clue where you are living. If you need more help you may use my offline email: reo43 at aol dot com
Erv Troyer Lagrange, IN
74 Sequoia
77 Birchhaven
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