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Phil
Phil, Mechanical Engineer
Category: HVAC
Satisfied Customers: 8430
Experience:  Retired HVAC/ Electrical & Boiler contractor. Industrial
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I have a Goodman Mini Split ductless system. It runs minutes

Customer Question

I have a Goodman Mini Split ductless system. It runs for 25 minutes producing 60 degree air and then shuts dow with the LED flashing in 7 flash bursts. Any ideas?
Submitted: 1 year ago.
Category: HVAC
Expert:  Phil replied 1 year ago.

Hello, tell me please about how old the system is, and if you have every cleaned the condenser coil on the unit outside or not.

We can go from there.

Customer: replied 1 year ago.
The system was installed last fall.The system has never functioned. It is at a cottage closed for the winter.The condenser and evaporator coils are brand new and shiny clean. The outside unit is located below a deck with all recommended clearances in place.The lines are both insulated. 15' as supplied with pre-charged system. They were vacuum evacuated three time before the charge was released.There was an initial issue with the amount of power being delivered. The power company was delivering 248 volts and the unit specifies 208-230 volts.A transformer was custom made to reduce the 248 volts to 224 volts and installed. It made no difference.After six 30 minute runs to auto shutdown the unit now runs for about an hour and a half to autoshutdown.Whether through the transformer or not when the unit shuts down it emits a status code of (7) led flashes when it auto shuts down. Can't find status code index.Unit is GOODMAN MSC183E15MC (Outdoor unit) with MSC183E15AX (Indoor Unit) wall mounted.Temperature differential while operating 20 degrees F. ie 80 degrees ambient with 60 degree airflow (but not really cold).The high pressure line and the low pressure lines at the outside unit fittings are equal temperature and are cool. (ie: not much cooling going on because no heat being returned to condenser unit outside to be dissipated).The outside unit runs when the inside unit is on.Doesn't sound like compressor is engaging but I have another of these units and it is also quiet and you don't hear the compressor over the fan and it works just perfectly.(also a cottage installation).
Customer: replied 1 year ago.
Posted by JustAnswer at customer's request) Hello. I would like to request the following Expert Service(s) from you: Live Phone Call. Let me know if you need more information, or send me the service offer(s) so we can proceed.
Expert:  Phil replied 1 year ago.
Hello again, If you can attach a few photo's of the unit situated under the deck taken from about 20 feet away that will help me sort this out for you.
I will submit an additional services offer for a phone call that you may accept or not, if not, we can continue here after I get the photo's.
Use the 'attach files' link at the bottom left corner of your reply box for that.
We can go from there.
.
Customer: replied 1 year ago.
I am three hours away from the place right now and it must be reached by boat. I was there yesterday.I do not have photos of the installed unit under the deck but here is the description:Location:
Customer: replied 1 year ago.
Location: Under 2 X 6 deck
Clearance over unit 18"
Clearance end of unit with electrical and lines to cottage 30"
Clearance front and rear of coils for air flow 20' (unlimited airflow)
likewise opposite closed end away from power and lines
unit is located level on stone foundation screwed down with TApCon screws and fender washers
wiring is outside tech cable and waterproof electrical fittings.lines insulated with foam insulation supplied with unit and wrapped with weatherproof tape supplied with unit for wrapping the lines.
lines run inside an insulated wall behind dry wall to inside unit.No water (dehumidification) is being produced while the unit runs (when it runs 1 1/2 hours to auto shutdown) in 80% relative humidity conditions at 85 degrees F outside (and inside) produces a gentle cooler air.20 Amp tandem breaker on 120/240 V Edison panelI was told that if L1 and L2 were reversed between the outside and the inside that the unit would shut down after a period with a two flash status code so I switched L1 and L2 between the inside (L1/L2/S/G) and the outside. Two flash status code now (7) flash status code.I would be happy to do the live voice thing but first I want to hear what the (7) flash status code means.
Expert:  Phil replied 1 year ago.
Hello again, Goodman is not listing the flash codes for that model, a good sign that it is Chinese made and short on paper work.
http://mobile.goodmanmfg.com/mobileapp/faultcodes/
So far I have not found it on line elsewhere.
There might be a code list printed on the outside units wiring diagram or on a sticker next to it.
There are hundreds of thousands of these ductless AC systems imported annually, from 6 or 8 different chinese manufacturers, and with all of them making changes and with different models frequently.
The chances of any one of us here having seen that particular model are in the range of one in ten thousand, or something like that.
Meantime if you like we can continue without the flash code, and look for an installation error.
Your description of the under deck installation indicates that it is getting plenty of air flow.
The next suspect is that it is over charged with refrigerant...or undercharged with refrigerant possibly due to a refrigerant leak.
An over charge of refrigerant will cause the unit to run hot, and trip the compressors heat sensitive overload... it will reset itself once the compressor cools off.
Chances of that being an accurate assessment are in the 70% range, I would need to know the low side and high side pressures to know if that is accurate or not.
The key indicator of an over charged system is demonstrated incompetence by the installer... those will say 'it has the proper charge in it'.
A competent technician will not say that... he will say 'the suction pressure is 107 psig with the room at 75F, and the compressor fully loaded, and the head pressure is 397 psig with the outside air at 102F, system uses R 410a refrigerant"
This is regardless that these systems come pre-charged with refrigerant.
That is the only correct way of describing the refrigerant charge (my numbers here are arbitrary to demonstrate the point).
Call the installer on the phone and ask 'how the system was charged'
That will tell us a lot about might be going on.
We can go from there.
Customer: replied 1 year ago.
Obviously I will have to go there and get some measurements taken I will get back to you then.
Expert:  Phil replied 1 year ago.
That will work.
You need to be alert to errors many inexperienced techs make... these will give you the pressures you ask for but *without* the inside and outside air temperatures at the same instant.
That is because they do not realize that in these systems temperature and pressure are in absolute lock step... when the compressor is running fully loaded.
That brings up the second issue, on these variable speed systems they will give you the temperatures and pressures correctly... but with the compressor not fully loaded... that amounts to useless information.
These techs will not know how to get the compressor to its fully loaded condition.. they will assume it is fully loaded, and give you temperatures and pressures without knowing if the compressor is fully loaded or not.
To get the compressor to its fully loaded condition it has to be over 80F outside, and temperature control has be set at least 3 degrees F cooler than the room temperature read out.
------------
These will charge a system so that it looks good them at a partial load situation, and in fact it IS good under partial load... but then when the weather warms up, the compressor goes to full speed and if the system is over charged for that situation you will get the high temperature safety cut out situation.
Installing these systems is best done by long experienced specialist in these systems... if the seller is not sufficiently experienced with this equipment... that will be the root of the problem.
Talk to the technician while he does these tests, if he is familiar with all these factors he will discuss then easily and at length with you... if not he will be brief and say "I am charging it to factory specifications".
Watch for that. Let me know which direction you are from the center of the nearest city if you need me to locate a specialist in these inverter driven ductless systems.
We can go from there.