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Phil, Mechanical Engineer
Category: HVAC
Satisfied Customers: 7537
Experience:  Retired HVAC/ Electrical & Boiler contractor. Industrial
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I have a trane unit that I getting cold as it should had a

Customer Question

I have a trane unit that I snot getting cold as it should had a couple of folks come out and gas level is fine .The big pipe will start out cold then turn warm I have a goodman air handler
JA: Did you double-check the thermostat's settings? And what about the filters?
Customer: yes
JA: Do you plan on doing the work yourself?
Customer: if posible
JA: Anything else we should know to help you best?
Customer: its a 3.5 ton unit on a 4.5 ton air handler
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: 4 months ago.
Category: HVAC
Expert:  Phil replied 4 months ago.

Hello, it is a huge red flag when you ask a technician about the refrigerant charge and he says 'its fine' or ' by the book'... a competent technician will tell you the exact suction pressure relative the indoor conditions at the time.

If that was the outfit that sold you 4.5 ton air handler to go with a 3.5 ton system, we have the second huge red flag on that company...that would be grossly worse than a laymans mistake.

If the air handler/cooling coil is almost 30% oversized compared to the condensing unit a wide range of difficulties will ensue... we can discuss them if you like, but for now I want to get this note off to you before its gets lost.

Expert:  Phil replied 4 months ago.

an oversize airhandler/cooling coil will run the suction pressure up on the compressor and cause it to overheat at times.

the other issue is that the suction pressure will be so high that dehumidification is slight at best, ***** ***** dehumidification worst case.

Expert:  Phil replied 4 months ago.

If the refrigerant flow control valve (TXV or piston Orifice) is adjusted to restrict flow though though the over size coil it can be made to work, but at the risk of trapping oil in the evaporator...

Expert:  Phil replied 4 months ago.

I am reasonably sure the outfit will tell you that have tens of thousands of these units installed last year, and yours is the very first one to have any issues.

That would be what I would expect from an outfit that did the work. Do they hold an HVAC contractors license? are they bonded and insured? how long have they been in business.

Let me know about all that, we can go from there.

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