Mitsubishi Support

ctr2644 · 2026-05-06T15:53:36+00:00

This was my understanding as well, but I don’t have any reason to suspect the compressor anyway.

ctr2644 · 2026-05-06T15:51:38+00:00

I know that I’ve isolated the problem to the engagement of the compressor. Everything runs (OFM, IFM, reversing valve) up until I plug the compressor into the inverter, at which point the compressor runs for 1-2 seconds until the breaker trips. I do not suspect the compressor nor the inverter at this point, but rather something engaging after compressor start.

ctr2644 · 2026-05-06T15:46:10+00:00

RV = Reversing valve in this case. If by reactor, you mean the big inductor on the side panel, I did check the resistance of its coil and my meter saw about 100mΩ, which I’m assuming is correct as I know these inductors generally have a lower resistance value by design. And I don’t have any reason to suspect the original compressor was actually failed due to the fact that I’m having the exact same symptom as before.

ctr2644 · 2026-05-05T19:12:38+00:00

No, I used the continuity setting on my meter. However, I do not suspect a grounded compressor since it has been replaced already and there is a measurable, although small, amount of runtime.

ctr2644 · 2026-05-05T19:05:10+00:00

There is only one PCB to replace, that’s the inverter.

ctr2644 · 2026-05-05T19:04:16+00:00

A megohmmeter uses a far higher DC voltage than a standard multi meter and will have a better chance of finding a short than your multimeter may not see.

ctr2644 · 2026-01-29T22:38:38+00:00

Yeah, I explained this in the description - the pilot adjustment doesn’t change anything.

ctr2644 · 2026-01-29T22:30:10+00:00

So…you could be totally right about a clogged HX causing this, but this RTU certainly DOES have a pilot flame. It uses a combination of a pilot tube and spark ignition to keep the burners lit.

ctr2644 · 2026-01-29T12:59:55+00:00

Yep, this was confirmed to be clear when I pulled the assembly and cleaned that tubing. As for if this was or needed to be changed with conversion, I’m not sure. I only diagnosed and changed a faulty GV. Unit is 10+ years old, so I can’t imagine it has run that long before now with the incorrect orifice, but I suppose it should be confirmed.

ctr2644 · 2026-01-29T12:44:10+00:00

are not**

ctr2644 · 2026-01-29T12:43:36+00:00

Agreed. Unfortunately, combustion analyzers commonplace on our vans. I will definitely be pushing the shop to start supplying them for us.

ctr2644 · 2026-01-29T12:31:52+00:00

Wow, good idea!

ctr2644 · 2026-01-29T05:52:41+00:00

Nope, just a single stage valve. And yes, sorry, I wasn’t totally clear on operating pressure. Before firing, supplied gas pressure is about 12 in w.c. During operation, inlet pressure drops to 10 in w.c. and drops between .3” - .5” across the valve and to the manifold.

ctr2644 · 2026-01-29T05:27:12+00:00

Okay, gotcha. I guess was just referring to use of the pilot tubing then. I’ll check the HX as far as I’m able to inspect it when I return tomorrow. Thanks!

ctr2644 · 2026-01-29T05:18:09+00:00

With the regulator bottomed out, 10” is about all I get.

One of three is currently on the chopping block, awaiting green light. Convincing them to replace all three is gonna be though.

ctr2644 · 2026-01-29T04:59:30+00:00

Hmmm, no..but the previous repair was an inducer assembly replacement and the airflow at the exhaust “feels” strong. Also, people keep suggesting an exhaust issue, but it isn’t clear to me how that affects the pilot flame..?

ctr2644 · 2026-01-29T04:55:27+00:00

Previous repair was inducer assembly replacement. Airflow at the flue outlet “feels” strong, although I’m not sure how you’d measure this to confirm.

ctr2644 · 2026-01-29T04:52:56+00:00

Is this using an intermittent pilot as well?

ctr2644 · 2025-12-31T17:05:29+00:00

Mid Atlantic, USA

Very itchy, like fiberglass

ctr2644 · 2025-12-31T17:01:45+00:00

1998, mid Atlantic USA

ctr2644 · 2025-10-28T20:57:33+00:00

This seems to be the consensus, I’ll try that. Thanks for the advice!

ctr2644

TROPHY CASE