Why did my AC compressor blow out?

[Jprps]

So just this morning my AC system purged out the back of the compressor and I have a couple of questions. It's still cold out and I'm not using the AC, (I assume it was cycling on defrost) but what caused the pressure to go that high? High pressure switch? It's a new compressor last summer. Also is the compressor garbage now? Or will it work again if I figure out the pressure issue? My dryer, expansion valves, condenser and thermistor are all new. Worked great last summer.

[hhow55]

Was the Freon system properly flushed?

[Jprps]

(04-14-2020 )hhow55 Wrote:  Was the Freon system properly flushed?

When I did everything last summer, yes.

[redbeard]

Mine just did the same thing last week. New compressor and dryer last year and system has been working flawlessly.
Pulled out of yard and had a funny smell, it was Freon leaking from high pressure valve on back of compressor. Would not reseal and all freon escaped.
Compressor seems to be pumping fine and it is quite and turns over.
New high pressure relief valve is $10 at Autozone, and I’m thinking of just trying that and see how it goes.
New genuine Sanden compressor is around $250 online and dryer is another $35 or so.

[Jprps]

(04-14-2020 )redbeard Wrote:  Mine just did the same thing last week. New compressor and dryer last year and system has been working flawlessly.
Pulled out of yard and had a funny smell, it was Freon leaking from high pressure valve on back of compressor. Would not reseal and all freon escaped.
Compressor seems to be pumping fine and it is quite and turns over.
New high pressure relief valve is $10 at Autozone, and I’m thinking of just trying that and see how it goes.
New genuine Sanden compressor is around $250 online and dryer is another $35 or so.

Yah mine blew out under high pressure, I though the engine went or something until I check the source. It would stop and start blowing off repeatedly. I shut the truck off and unplugged the compressor for now. Luckily were having a cold spring in canada.

[Rawze]

the high pressure sensor is used to turn on the engine fan at 315 psi and will kick the compressor clutch out at roughly 350 psi. if it blew out, either the clutch is stuck, the relay for the clutch is stuck, or the sensor is reading incorrectly, or engine fan did not come on and it did not kick out in time ... etc... OR-- the blow-off valve is failing and blowing off at too low of a pressure.

that is what I know about them o9n my own truck any ways... diff trucks may be different.

[Jprps]

(04-14-2020 )Rawze Wrote:  the high pressure sensor is used to turn on the engine fan at 315 psi and will kick the compressor clutch out at roughly 350 psi. if it blew out, either the clutch is stuck, the relay for the clutch is stuck, or the sensor is reading incorrectly, or engine fan did not come on and it did not kick out in time ... etc... OR-- the blow-off valve is failing and blowing off at too low of a pressure.

that is what I know about them o9n my own truck any ways... diff trucks may be different.

Good to know. Is the compressor okay after it blows out? Does that relief valve reset itself? Also where is the relay for the clutch? Gunna start trouble shooting I suppose.

[smorgan87]

As long as the systems clean and the compressor didnt lock up at the same time it blew off u can fix the cause of thenoverpressure and recharge

[Jprps]

I'll have to plug it back in and check to see of its cycling yet. Not sure how much refrigerant it lost. It seems to me the fan wasn't kicking on at idle at all and it built too much pressure. I thought Id the high pressure sensor failed it would keep the fan running as a fail safe? Can I check the sensor with an ohm meter? The fan not cycling to bring the pressure down is what puzzles me.