System on Fire Engine

[Dgreen]

This is a truck at work. System reported to not be cooling. Recovered the refrigerant. It had 1.5 lbs. System capacity on the drivers door says 5.5 lbs. low pressure was 2 high side was 200 with the high idle in. Does this point to a leak with a restriction in the system or would those numbers be possible with just a leak and low charge?

[bohica2xo]

Does not sound reasonable for just a low charge. What sort of system? CCOT or TXV?

I recall you had a truck with a half charge of refrigerant and a gallon of oil once. Any chance the same guy was there?

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[Dgreen]

There is a chance, I’m the only one that has worked on it since it was bought in 2003. I’ve done quite a bit off work to it. The most recent was when it had similar symptoms in June of 2018. Changed the expansion valve and dryer. It’s worked until just recently. Has dye in it. No obvious leaks noted so far.

There is a site glass for the oil level in the side of the compressor. At one time the glass was full. Found out later that it should only be half way up the glass if I remember correctly. Oil level doesn’t completely fill the site glass now, but not far from it.

[bohica2xo]

Well, since you have recovered it, check the TXV inlet. Do you recall if the TXV had an inlet screen?

TM 31 compressor has a lot of volume, it is possible for those pressures to exist with high enough ambient.

[Dgreen]

I’ll work on it again Sunday. The evap case is already off so we can look for dye. It won’t be much work to check the inlet.

[Dgreen]

Didn’t find any debris at the expansion block. Vacuumed for 10 minutes and it went down to 560 microns. Valved off the pump and it continued down to 530. It stayed at 530 for 10 minutes with no rise. Turned the pump back on and ran it for an hour total and it went to 510. Charged it with 5.5 lbs of refrigerant. Ambient temp was 83, 1200 rpm’s, 14 on the low side, 225 on the high side, vent temp was 47.

[bohica2xo]

High side numbers are looking pretty solid. It is moving some heat.

Low side is not terrible, the 14 psi and 47f discharge are a little harder to reconcile. Is this an E-One unit? Might be within their parameters.

[Dgreen]

It is an E1.

[tbirdtbird]

Did you find the leak?

[Dgreen]

I wasn’t able too find a leak.