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When ACs high pressure switch goes bad!

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PAUL161

PAUL161

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Had to install a new AC pump on one of my tractors when the original went Boom! It over-pressurized when the high-pressure switch went bad and didn't shut the clutch off! It created quite a mess and sounded like a gun going off! o_O
AC Pressure switch Bad.jpg
 
I'm surprised a hose or the evap unit inside the car didn't blow up first - those seem like they woud be more fragile than the solid cast compressor body.
 
Paul, your tractor has A/C? Man you're all kinds of fancy.
YakkoWarner said:
I'm surprised a hose or the evap unit inside the car didn't blow up first - those seem like they woud be more fragile than the solid cast compressor body.
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That looks like a cast aluminum body.
 
I was surprized it didn't blow a line first also. I will say that when it blew, it sure got my attention! The right side of the tractor shouldn't rust for many years! o_O :devilgrin:
 
YakkoWarner said:
I'm surprised a hose or the evap unit inside the car didn't blow up first - those seem like they woud be more fragile than the solid cast compressor body.
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PAUL161 said:
I was surprized it didn't blow a line first also. I will say that when it blew, it sure got my attention! The right side of the tractor shouldn't rust for many years! o_O :devilgrin:
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I'm no AC engineer but could it be because the soft rubber lines are on the low pressure side and the blowout happened on the high pressure side, where ether are steel pipes and not hoses?
 
Having installed an AC system, the hoses do have a rather high burst pressure. The evaporator is on the low pressure side, so it doesn't see much pressure. I'm surprised it was the compressor and not the condenser. My guess is that liquid Freon backed up into the compressor and hydraulic lock occurred.
 
Actually, I thought I blew a tire, had that happen before and it sounded the same. The new compressor and switch and the AC work fine. 95F yesterday mowing pasture, kept the cab closed up, and was comfortable! :thumbsup2:
 
Almost 100 degrees yesterday, had to mow 2 fields, the cab was all closed up, and the air working fine! One field along the road drew a bit of attention when some cars went by, I guess they thought the guy out there mowing with the cab closed up was crazy! :devilgrin:
 
And now I know why Mazda includes a relief valve on the compressor!

(Worked at a Mazda dealership in another life; one day a 626 pulls in, hissing and blowing a white cloud like a Stanley Steamer. The high-pressure switch had failed, but the relief valve opened to save the compressor. Kind of neat to have witnessed it, and really glad I wasn't as close to witness yours! )
 
JHaydon said:
And now I know why Mazda includes a relief valve on the compressor!

(Worked at a Mazda dealership in another life; one day a 626 pulls in, hissing and blowing a white cloud like a Stanley Steamer. The high-pressure switch had failed, but the relief valve opened to save the compressor. Kind of neat to have witnessed it, and really glad I wasn't as close to witness yours! )
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I think that is a great idea! I wonder why the relief valves aren't incorporated on all AC compressors as a safety device? Probably cut back too much on the profit margin! :rolleyes2:
 
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