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-   -   r-22 coil leaking (http://www.diychatroom.com/f17/r-22-coil-leaking-151977/)

slash5bmw 07-30-2012 09:12 AM

r-22 coil leaking
 
My brother had a hvac tech come out to his house and was told that his coil was leaking and needed to be replaced. It's a carrier 5 ton unit and about 10 years old. It does look very rusted and had a block of ice on it.

The questions I have are the following:

-Since there's still refrigerant in the system, does the tech evacuate the system or does he hook the manifold gauges to the condenser and run the compressor while the liquid line valve is closed? Once the pressure goes to zero on both gauges, shut the low side suction valve off so the refrigerant is stored in the condenser. Is this how they save time and money on refrigerant?

-Will any Carrier 5 ton coil work in the unit? I saw this one on ebay for $499
http://www.ebay.com/itm/5-TON-NEW-EV...ht_3949wt_1398

-I believe his current system has a piston. Is a txv recommended over a piston? The line drier near the condenser will also need to be replaced since the system will be opened.

Any thoughts?

Thx

Slash

raylo32 07-30-2012 09:30 AM

Yes, it can be "pumped down". Then change coil, evac, bring it back online, then adjust charge. That's how my R22 coil replacement was done. Also went from piston coil to TXV coil and added hard start capacitor kit since TXV coil retains pressure in the liquid line which puts more startup strain on the condenser.

slash5bmw 07-30-2012 11:00 AM

Thanks. A hard start kit is a good idea and they are cheap.

Slash

Doc Holliday 07-30-2012 12:59 PM

This is where things become iffy. I don't like pumping down any left over refrigerant on a system with a leak to reuse because with a leak you'll be sucking in air through that leak as well. Then you'll vacuum the line and release trapped air back into the lines.

I've done it but don't prefer it nor recommend it. You'll fix the leak and next thing is the compressor goes due to that air/moisture you pumped down.

scottmcd9999 07-30-2012 03:52 PM

Quote:

Will any Carrier 5 ton coil work in the unit? I saw this one on ebay for $499
No. The coil you found does NOT have a drain pan, and in fact looks to be one designed to be installed in an air handler. If you have a compatible air handler, and the drain pan is okay, and you can easily remove the coil and reattach the pan, then that coil will work. Otherwise, you'd have to be sure that the coil is compatible.

I too agree with the "iffi-ness" of pumping down a system with a leak. Too much of a chance of moisture and such, even with a good, deep vacuum on the exposed parts. A line drier would help, of course, but that won't solve the entire problem.

turnermech 07-30-2012 05:20 PM

Quote:

Originally Posted by Doc Holliday (Post 977657)
This is where things become iffy. I don't like pumping down any left over refrigerant on a system with a leak to reuse because with a leak you'll be sucking in air through that leak as well. Then you'll vacuum the line and release trapped air back into the lines.

I've done it but don't prefer it nor recommend it. You'll fix the leak and next thing is the compressor goes due to that air/moisture you pumped down.

stop the pumping down when you still have positive pressure in the refrigerant lines ( say 10 psi or even 5) nothing can get in until you pump down below 0 psi.


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