P4 Error Code On Mini Split New install

[smokinaces]

Went to a call today. Mini split air handler was displaying a P4 Error Code. When I hooked up my gauges the standing pressure was between 230-240psi for a 410A system. Inside Air temp must have been about 80 degrees .

Compressor kept short cycling. Any idea what it could be? I thought my standing pressure seemed high. Noticed the compressor would cut out at 150psi also.

BRAND: PREMIUM
MODEL: PIAW24180B

[pecmsg]

Contact Tech Support!

[cfe]

I know Fujitsu will do that if min lineset length too short or too long.
Low refrigerant charge will also short cyling.

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[smokinaces]

Went back today and same symptoms persisted. Standing pressure of 240 cutting off at 150.

Tech support said it could be the board but I don't think it's that. The pressures don't look right to me.

Upon releasing the refrigerant after pulling a vacuum I opened the suction line first before opening the liquid line.

Could this have been an issue?

I recovered all the refrigerant and charged it again. Also took amps on the compressor and it ramps up above the water 12amps to around 17 amps before it cuts off.


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[joeysmith]

Outdoor fan check out good?

[dreaton]

I'm having the same error code of P4 on a Mr. Cool mini split heat pump. Outdoor unit will not run, indoor fan runs. there is 125 psi standing pressure; 230v from disconnect; Communication voltage, 1-2, 230v; 1-3, 140v, 2-3, 63v; 1-G, 120v; 2-G, 120v; 3-G, 41v.

I have attempted to contact Mr. Cool tech support, leaving a voice mail msg and emailing support, haven't received any reply.

Any suggestions on going forward?

Customer says he has talked to support, he has followed their recommendations, has had an electrician check voltage twice, (I'm not sure if this includes the communication voltage check), has also had another hvac contractor come out, said it was low, added refrigerant, but still outdoor unit will not run; support has sent him the outdoor control board and indoor board as well, none of this helped. I found online its possible the valves were not opened or not all the way; had him check that he says they are back seated (all the way open).

[pecmsg]

Homeowner purchased equipment on line?

[dreaton]

Yes

[pecmsg]

And who installed it?

[dreaton]

I don’t know

[pecmsg]

Personally I'd walk away but if you choose to continue 1st Pull and weigh the charge. Compare to manufactures recommendations. If short find and repair the leak.

With Mr. cool it's sometimes cheaper to just replace it!

[dreaton]

Yes, I have only been there once. The customer called me back Wednesday. I tried contacting Mr. Cool again yesterday. No response yet. I was planning to recover, evacuate and weigh charge in if I return.

Thanks

[pecmsg]

No need calling tech support without being there, thats the way it works. Getting anything from Mr Cool is another story!

[AtticAce]

Mr Cool is DIY, but is pretty much fool proof. Line set is pre-charged and set length it's not supposed to be cut nor is refrigerant supposed to be added or removed. There are no flares to leak. The only possible explanation is wrong voltage was applied, power surge, or the wiring was mixed up. If power is applied to the communicating connection the board is toast. I see this with all mini splits on a regular basis.

10 years ago installing a commercial Samsung unit of 460 volt 3 phase the supplied cable was color coded white, red, and black with black 1, red, 2, and white 3, only issue was the numbers were different on the other end. While my brother hooked up the outside unit I did the inside on start up fried board, second board fried, then I caught the issue. Samsung then learned why so many boards had fried on these units over the last couple of months.

Mr. Cool is a disposable unit, as such the kit does not include a surge suppressor, with one the board will at some point be fried (most times after the warranty expires).