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Phil
Phil, Mechanical Engineer
Category: HVAC
Satisfied Customers: 5648
Experience:  Retired HVAC/ Electrical & Boiler contractor. Industrial
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I have a 1710a model. After it runs I get 4 red

Customer Question

I have a 1710a model. After it runs for awhile I get 4 red light blinks error code. I have 300 high pressure side and zero on auction side. What is going on with this?
Submitted: 1 year ago.
Category: HVAC
Expert:  Phil replied 1 year ago.
Hello, This should be the service manual for it. I will post it here for future reference.ftp://ftp.aprilaire.com/Fulfillment/Dehumidifiers/Aprilaire_Model_1710A_1750A_1770A_Dehumidifier_Technical_Manual.pdf Tell me please if the high pressure side maintains 300 psig, and if the suction side never goes above zero or not. We can go from there without any time limits. .
Expert:  Phil replied 1 year ago.
http://screencast.com/t/3WyXjC4hSo far, that looks like the most suspect component. Locate its connection on the board and unplug one of the connections to it and let me know what happens. Next, locate its sensing element on the cooling coiling coil, remove it and hold it in your hand as you run the system, let me know what happens. We can go from there.
Expert:  Phil replied 1 year ago.
Tell me please if the suction line that comes back from the cooling coil to the compressor is cool, cold or frosty where it attaches at the compressor.
Customer: replied 1 year ago.
Pressure doesn't change and after it hits the error code it stops running. The 2 small linesctgar go to the txv valve freeze up. The auction line itself us not cool.
Customer: replied 1 year ago.
When I unplug one of the lines you asked about, the unit shurs down and I get 6 red flashes for werror code.
Expert:  Phil replied 1 year ago.
Thanks,
Tell me please if this system uses R-410a, or some other refrigerant and if you have added any refrigerant to the system or not, and if so what type.
If the two small tubes between the TXV and the cooling coil are frosted, then the TXV may be blocked with a tiny ball of ice *inside* the valve at the orifice... or there may be a refrigerant leak in the system.
I need to know how warm the room is surrounding the dehumidifier, and if you have cleaned its condenser coil or not.
.
Customer: replied 1 year ago.
This is a 410 system. I have tried adding refrigerant and then took it back out when the pressure increased on high side and no change on low side. Only put 8 oz in. The room temp is about 74 with lots of humidity. This unit does this after it has sat for days. No chance of ice in txv. I got this unit uses so I have no idea if it has been worked on before.
Customer: replied 1 year ago.
Coil is clean as well
Expert:  Phil replied 1 year ago.
Hello again, just in case, make sure that *both sides if the coil are clean... sometimes the dirty side of the coil is not visible. 8 ounce is a lot of refrigerant for that unit, it most likely holds less than 2 or 3 pounds, the amount is not listed in their specs, but the law requires that it be on the model number name plate.. can you tell me what that reads? If there is moisture in the system, and the system is warm as if sitting for days or weeks, ice will still form in the TXV within minutes... if there is moisture in the system... in this case the chances of that are in the 30% range, not 100% however. If it has been worked on before, and someone put R-22 in it, that will cause the POE oil used in R410a units to clot in some cases, and that will block the refrigerant flow at the TXV. Locate the sensing element attached to the power head on the valve, remove it and hold it in your hand until it is warm, tell me if that lets the suction pressure rise or not.... if not replace the TXV.... if it does allow the suction pressure to rise, look for a nut on the back end of the valve that you can remove to reveal the superheat adjustment and turn it counter clockwise a turn or two and tell me if that runs the suction pressure up or not. We can go from there.
Expert:  Phil replied 1 year ago.
If you are in doubt about there being a super heat adjustment on the valve, use the paper clip icon above to send me a picture of it.

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