Replacing R22 system with r410a

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Old 04-24-13, 11:56 PM
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Replacing R22 system with r410a

O.K. , We are getting prices on our home hvac system . currently have 15 year old r22 AC. Will be replacing with r410 system. 70k gas fired hot air,3 ton condenser,Line sets , A-coil with txv, and second price on A-coil with flowrator as metering device. Most recommended txv over fixed orifice,question is which if any is preferred and why ? Any input will be greatly appreciated.
 
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Old 04-25-13, 08:51 AM
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TXV (Thermostatic Expansion Valve) meters the refrigerant to the evaporator using a thermal sensing device that monitor the superheat.

The valve "meters" the refrigerant based on load on the evaporator. A much smarter system.

There are no questions that TXV are more efficient but for some reason here in Florida they are rarely used on straight cool system.

-
 
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Old 04-25-13, 05:23 PM
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TXV over fixed metering device!
 
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Old 04-25-13, 11:48 PM
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Thanks for the opinions guys , txv it will be !
 
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Old 04-30-13, 10:58 AM
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Will be replacing with r410 system; 70k gas fired hot air,3 ton condenser,Line sets.
A-coil with txv, and second price on A-coil with flow-rator as metering device. Most recommended TXV over fixed orifice, question is which if any is preferred and why ? Any input will be greatly appreciated.
ALWAYS Get the TXV...

Am wondering if furnace & A/C are over-sized.
Was a load-calc performed?

Tell us where you live & square footage (sf) of your home; lot of windows; double-pane or S-Pane with storms?
 
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Old 04-30-13, 01:01 PM
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TXVs vary the amount of refrigerant entering the indoor coil to get optimal performance as operating conditions change. (outdoor temp, indoor temp/humidity)

Orifices are completely fixed and the amount of refrigerant entering the coil drops as it gets cooler outside, leading to slightly reduced performance.

On the other hand, a txv is a moving part which can fail -> I would go for a fixed orifice if approved by the manufacturer. In cooler weather, you don't need as much cooling capacity anyway.

Regardless of what kind of metering device the installer puts in, if the indoor coil isn't properly matched to the outdoor unit, the a/c isn't properly charged and/or the airflow is off (too much or too little), the system won't operate at rated capacity or efficiency.
 
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Old 04-30-13, 01:29 PM
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Good points, Muggle.

However, the reason I want a TXV metering device with most conditions, is that, when the outdoor temp drops there can be a problem due to short-cycles & the cooling coil not being cold enough to condense adequate amounts of moisture from the indoor air to keep humidity at 50% or lower.

On cooler days, with reduced runtimes, you need a really cold coil, & I prefer an adjustable TEMP-SWING room thermostat to reduce short-cycling; short-cycling does not allow even an adequately cold coil to condense enough moisture from the room air.

Also, many A/Cs are oversized which greatly adds to the humidity problems when temps are not real high...


Some TXVs are super-heat adjustable, so you can adjust for optimal latent performance.
 
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Old 02-27-14, 10:06 AM
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txv

Can you replace the txv and use a R22 compressor with a r410a condensor?
 

Last edited by rcshane; 02-27-14 at 10:07 AM. Reason: Misspelling
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Old 02-27-14, 12:37 PM
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Can you replace the txv and use a R22 compressor with a r410a condenser?
NO!

Read more: http://www.doityourself.com/forum/ai...#ixzz2uYLXVHRH

Everything has to match the refrigerant type.
If R410a, all components have to be compatible with R-410a.

I understand U can use an R-410a evaporator coil with an R-22 condenser, however, the refrigerant metering device, such as a TXV, has to be compatible with R-22. If this is questionable (PROS) please post further information...
 
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Old 02-27-14, 01:18 PM
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Thanks. I was told that you could use different parts if you changed the txv.
 
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Old 02-27-14, 01:59 PM
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Thanks. I was told that you could use different parts if you changed the txv.
You were told wrong; the condenser has to match the refrigerant that is being used, as does the TXV metering device. All components need to match the refrigerant type.

You should even use stronger copper tubing for R-410a.
Also, your manifold gages need to be for R-410a's much higher pressures.
 
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Old 02-28-14, 07:24 PM
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I agree with Muggle, I am not saying the TXV is not good, in fact, it is a better device compare to the FIX in terms of functionality. But here is my reason: during the last 2 years, I have fixed many many TXV problems, but not even one FIX orifice problem. So unless you have a special reason to use TXV, I suggest the simple one, FIX.
 
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Old 03-01-14, 08:03 AM
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Everything I have read previously indicated a TVX for R410a ? But all may have been talking about Heat Pumps ?

I have also read A-Coils made over the last few years are rated both R-22 & R-410a ?

When I was researching for a mini split ( which I installed this last summer ) Mueller copper tubing was recommended for R-410a . This is what the local Johnstone Supply stocked . Which is where I bought the mini split . Bought the copper there , also .

I have read to replace the old copper tubing , of feasible , when going from R-22 to R-410a . If not , flush very well ?

God bless
Wyr
 
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Old 03-01-14, 08:49 AM
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I have also read A-Coils made over the last few years are rated both R-22 & R-410a?
I believe that is true concerning the evaporator coils, however, the refrigerant metering device has to be selected for the type of refrigerant being used in that system.
 
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Old 03-01-14, 09:16 AM
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I have no doubt you are correct . Most of / all the R-22 A/C units I have seen have orifices .

The temperatures and pressures are not the same . And I am guessing a TVX would give more accurate flow control ?

Why did they quit putting sight glasses in A/C / HVAC systems . Is that when they started moving away from TVX valves ? Because orifices were cheaper ?


God bless
Wyr
 
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Old 03-01-14, 09:23 AM
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Contractors installed the sight glasses usually only on the TXV units.
 
 

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