Date: Sun, 02 Sep 2007 09:39:37 -0400 From: Steve B. <nonenospam.com> Subject: Re: [XP] Sporadic aircon
On Sun, 02 Sep 2007 10:56:52 GMT, "Mrcheerful" <nbkm57nospamail.com> wrote: > >"Colin Stamp" <col.dustbinnospamp.plus.com> wrote in message >news:td3ld35g32isos1ag912fl96ktfaf9dcs7nospamcom... >> On Sun, 2 Sep 2007 09:38:51 +0100, "moray" >> <mtb_hyphen_rulesnospamail.co.uk> wrote: >>> >>>Most likely a knackered clutch on the compressor. >>>Connect a test lamp from the clutch power wires on the compressor, and see >>>if it's still getting power when the system stops working. >>> >> >> Could be. The next part of my cunning plan is to check the clutch is >> pulling current. >> >> I'm still wondering if there might be a refrigeration problem which >> could cause the high-side pressure to intermittently drop to a >> "switched off" level even with the compressor running though. >> >> Cheers, >> >> Colin. > >moisture in the system can cause this, it freezes to form a plug, then melts >etc. > But when you get a blockage in the system high pressure goes through the roof and low pressure drops very low (or even to vacuum if the switch doesn't cut the compressor off). His pressure is going back to an "at rest" pressure. You need to know if the compressor is turning or not when the problem happens. The LED is a good idea but an LED will light with virtually no current. A compressor clutch needs a few amps to pull it in. If you have a poor connection / bad switch somewhere in the loop it is possible for there to still be enough oommmppf to light an LED and not pull in the compressor. Kind of like having a dead battery... The interior lights will still come on but the starter won't spin. Steve B.