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airheatman, HVAC Technician
Category: HVAC
Satisfied Customers: 8052
Experience:  Furnace, A/C and heat pump specialist.
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I am receiveing a 84 pressure lock out message on a brand

Customer Question

I am receiveing a 84 pressure lock out message on a brand new carrier infinity A/C and air handler (3 ton units)
JA: Did you double-check the thermostat's settings? And what about the filters?
Customer: Yes, and the system is brand new so the filter a clean
JA: Do you plan on doing the work yourself?
Customer: depends on the solution
JA: Anything else we should know to help you best?
Customer: nope
JA: OK. Got it. I'm sending you to a secure page on JustAnswer so you can place the $5 fully-refundable deposit now. While you're filling out that form, I'll tell the HVAC Technician about your situation and then connect you two.
Submitted: 9 months ago.
Category: HVAC
Expert:  airheatman replied 9 months ago.

The error code is usually caused by a restriction in refrigerant circuit.

1. Did you open service valves on unit(Silly question but I have to ask)

2. When you first start up, what do pressures do on gauges? (Does suction immediately go into a vacuum?)

Customer: replied 9 months ago.
1) yes, and 2) the service installer repressurized the system to the correct specs, but I still keep getting this message. They have been wait a response from the carrier distributor since last Thursday with no response as of yet.
Expert:  airheatman replied 9 months ago.

Does unit work, just getting this error or is it actually shutting down on low pressure?

Customer: replied 9 months ago.
The system works for a bit and then it turns itself off and displays the 84 pressure lockout message
Expert:  airheatman replied 9 months ago.

OK you most likely have a bad txv (thermal expansion valve) sticking and not allowing refrigerant to flow. If you can connect gauges and se if suction side is going into a vacuum, that will verify.

Customer: replied 9 months ago.
Thank you I will try to see if that is the problem
Expert:  airheatman replied 9 months ago.

Let me know and we can go from here.

If you have further questions, please let me know.

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