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AC doesn't cool at idle 2m4 by JMTUT
Started on: 07-13-2018 06:26 PM
Replies: 6 (194 views)
Last post by: JMTUT on 07-20-2018 10:08 PM
JMTUT
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Report this Post07-13-2018 06:26 PM Click Here to See the Profile for JMTUTSend a Private Message to JMTUTEdit/Delete MessageReply w/QuoteDirect Link to This Post
My AC cools when at 2000-3000 Rpms OK but doesn't cool at all at Idle. This is the original compressor (as far as I know) Does this typically indicate a low charge or a worn out compressor? I have 49 lbs on low side. (Still R12)
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RWDPLZ
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Report this Post07-13-2018 06:35 PM Click Here to See the Profile for RWDPLZClick Here to visit RWDPLZ's HomePageSend a Private Message to RWDPLZEdit/Delete MessageReply w/QuoteDirect Link to This Post
Are the condenser coils straight and clean? Is the fan running with the AC on at idle? What are the static low and high side readings (and ambient temperature when readings were taken)? Since R-12, is the compressor kicking off at 25 psi low side? Any debris in the HVAC box (leaves, mouse nest) around the evaporator?
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Gall757
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Report this Post07-13-2018 09:24 PM Click Here to See the Profile for Gall757Send a Private Message to Gall757Edit/Delete MessageReply w/QuoteDirect Link to This Post
I vote for junk in the heater box.
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JMTUT
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Report this Post07-14-2018 01:36 AM Click Here to See the Profile for JMTUTSend a Private Message to JMTUTEdit/Delete MessageReply w/QuoteDirect Link to This Post
Cleaned the heater box. Condenser is ok. Have not checked high side pressure. Must be time to buy a gauge set.
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larafan
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Report this Post07-15-2018 09:10 PM Click Here to See the Profile for larafanSend a Private Message to larafanEdit/Delete MessageReply w/QuoteDirect Link to This Post
49lbs at idle is not going to cool well. You do need to check both pressures. You need to see 38-40lbs low side.
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Dennis LaGrua
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Report this Post07-20-2018 08:50 PM Click Here to See the Profile for Dennis LaGruaSend a Private Message to Dennis LaGruaEdit/Delete MessageReply w/QuoteDirect Link to This Post
Sounds like a low refrigerant level . If its still an R-12 system then the low and high side pressures will be significantly different then if it was an R-134a retrofit. Check with a gauge set. If you low on refrigerant then first find the leak, fix it and do the R-134a update . Common leak areas are the compressor seals and at the O ring fittings. You will need to add leak detector and have an UV light to trace leaks. Repairing the A/C system is much more involved than this so read the service manual and follow the proper procedures..

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JMTUT
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Report this Post07-20-2018 10:08 PM Click Here to See the Profile for JMTUTSend a Private Message to JMTUTEdit/Delete MessageReply w/QuoteDirect Link to This Post
Thanks Dennis,

I have a copy of the service manual and I'm going to pick up a gauge set tomorrow.
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