McQuay AGS

[ascj]

I returned today, to check on it. Circuit out on fault again. Log showed slide valve position at -1.1% and target at 0.0%. Circuit was off, when failed. Hmm.

Hooked up my meter and reset circuit. Compressor started loading(verified by amperage), but slide position at -0.9% and my current reading at 3.8mA. No lights on indicator module. Pumped down circuits and reset power to chiller, still no lights on module.

Ended up throwing a old module on and recalibrating. Have another module on order.

[freonrick]

just dont unplug it while it is running, either end.

[steveoo]

don't over tighten screw on the plug.

[ascj]

Got a new slide valve sensor assembly in today. It looks like they changed it again.

[steveoo]

Don't overtighten screw on plug. Leave cap off micro switch till calibration is complete,When complete then power down unite replace cap and plug,then turn power back on.To calibrate Set compressor slide to 0% then press miro switch till it blinks red then increase slide postion to 100% slowly then press micro switch should blink green calibration should be complete.

[ascj]

Replaced the slide valve sensor assembly, again today. When I pulled the old one out, I noticed it was worn. Seems pretty bad for only 4 months.

What eats me......2 year old chiller. Circuit 2 compressor constantly with slide valve faults. Circuit 1 fine. Replace slide valve sensor with new design. Worked fine for 4 months. Then head dies. Replace with another new design. Results unknown.

I attached a couple of photos. The first is the two older sensors. The top is the original and the bottom is the replacement. The next photo is the one I just put in. The third photo shows the last replacement wear at just 4 months.

Why McQuay can't tell me why they keep redesigning the sensors?

[freonrick]

check your email.

[ryan1088]

I think Rick is giving you the holy grail!

[automig]

wow. i have a chiller i recalibrate those slide valves annually. maybe i should pull them. i can't believe you're seeing that kind of wear!

[ascj]

Freonick thanks for the pdf! Great info.

As far as wear.....I only have had issues with this one compressor. And I have only seen the compressor lock out once on "slide valve fault". That was the last one that the head took a crap. All the rest of the lock outs occurred when I wasn't there.

The original had the ball bearing end. Inspected slide when I replaced it.....didn't see any grooving on it. But replaced it with the new and improved model. Also replaced all wiring...to rule that out. Fine for about 4-5 months, then repeat failures. New model has alot bigger end on it. We will see.......it's been ok so far.

[ryan1088]

I'm kinda sad that half of these model chillers we take care of got taken away from us. They really are interesting and challenging machines to work on!