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R22 to 407A - Do We Need To Replace the Inside Valve/Meter?

9.6K views 24 replies 7 participants last post by  HVAC_Marc  
#1 ·
The compressor on our old 20 Trane XE80 (Furnace and AC) system has failed and we are looking at two options.

Option 1: we replace just the condenser (everything outside) with a Guardian/York, draining the R22 fluid and replacing it with 407A. This contractor says we don't have to touch anything inside the house or the garage - just drop in the new outside unit. Then, when the time comes for the full replacement we can reuse the outside equipment.* He says it will work because the Trane's "inside valve that meters the ac fluid which is located in the stack in the garage" has an TXV on it (this is my wording). This is the best fit for our crazy strapped budget but.........

Another company says: that if you replace the outside unit with a new unit that uses 407A we need to also change out the "inside valve" which will require taking apart the entire stack (including the furnace) which may cause other things to break. The reason the valve must be replaced is because the 407A operates under different pressure and the "flow regulators" are not the same. He also says that the rest of the system might leak under the different pressure and is adamant that this should never be done.

Option 2: get a new compressor and drop it in, leaving everything else there "as is", and drain the R22 and replace it with Nu22. Typical caveats - many other parts could go, no warranty. He really does not recommend it.

I don't have an previous relationship with either vendor so I am still feeling my way.

*He says that if we can find it in our budget to pay for the full replacement, that is the better option because they use Bryant/Carrier equipment which is better quality. So re-using the Guardian/York is like adding budget tires on a new car. However, he understands that it may be a full year before we can afford the new replacement.
 
#2 ·
Ideally you'd want a 407c TXV. I find it difficult to believe that a replacement of the TXV requires a complete system tear down and take-apart. Usually it's just "access the evap coil, change the part, close it back up".

However, a good tech can make 407c work with a 22 TXV.
 
#6 ·
I think the system tear down has to do with the fact that the heating section and the return are stacked on top the cooling ad they are are all taped together

Return
Heater
Cooling Box
Stand

To access the cooling box everyone has said they have to disassemble the furnace...might be able to leave the flue in place (which is huge almost 4 feet across so they are not certain if it will stay in place if the stack is removed). I'll see if I can upload a photo.

Tech 1 says nothing needs to be replaced except the outside unit if they use 407a fluid and a 407a rated outdoor unit.

So it would be:
407a (outside unit)
R22 coil drained and replaced with 407a fluid (inside)
original TXV valve that was built for R22


The only reason we're not considering replacing the inside coil to match the outside unit is because Tech 2 claims that if he takes the entire system apart he cannot guarantee it won't break. Also, he thinks the lines should be replaced because they will leak with the new type of fluid...basically he only wants to do a full new install.

The other 2 companies we brought out are the same. Only full installs.

No one as offered a 410 fluid option.
 
#3 ·
Do it right, get a 410 outdoor unit AND MATCHING COIL. When you mismatch a coil with an outdoor unit, who knows what SEER and capacity you'll end up with. Since evap coils are usually the source of leaks in a system, why reuse an oldie to save a few beans?
 
#8 ·
Right now nothing is leaking (but that may change). But since the only way to replace the evap coils is by removing the furnace (and maybe also removing the flu) the cost is...thousands of dollars of savings.

To put it bluntly:
No company is offering replace both the evap coil and the outside unit .

Company 1 (outside unit only)

Company 2 (and 3 and 4 that I did not post about): replace everything. I was reporting on what Company 2 was saying to see if Company 1 was making sense since no one else wanted to do any repairs only full install.
 
#9 ·
Strange they did not offer a 410a option. I don't think either provided ALL options for you. Maybe im wrong but i think one should be able to pull a furnace and put it back without breaking a bunch of stuff. That sounds to me like they are trying to get you to replace the furnace too or not wanting to do the work. I'd suggest another bid from a 3rd company with more options.
 
#11 ·
Update: the 5th estimate came in and said you can replace the outside unit with an 470c Guardian and avoid disturbing the inside stack. However....when the time comes for a full size replacement, the outside unit cannot be used as "all new units are 410a". So the money will be wasted.

How the heck is your average consumer supposed to make sense of this?
 
#13 ·
Quite true.

Our company always offers all options.

Repair is always less, but not always the best choice.

A 407 condenser would work for several years, if not 10 or more... not sure wasted is the best term. 410a comes with refrigerant, 407 does not. 410 with a matched coil would provide correct capacity and efficiency. 407 would not.
Repairing the R22 system could be the correct choice.
What is wrong with it, if it's not leaking?
 
#15 ·
The compressor valves stopped working. The fan still runs. Thread here: http://hvac-talk.com/vbb/showthread.php?t=2194066&goto=newpost

So when the time comes to replace the entire system, we'd still need to get a new compressor (to match the new coil etc) and could not reuse the 407 one. I think that is what the tech today was explaining.

If the new condensor using 407 does not come with refrigerant, where does it come from? The evap coil and everything inside will stay the same (R22). I thought the tech said he'd be draining the whole system and then installing the 407c condenser.
 
#14 ·
I reread the OP...
bad compressor, that is a big repair. I wouldn't recommend unless you had to have the lowest repair. Why use N22? If YOUR 22 has not leaked out, reusing it should be ok, unless it has burned ...
 
#22 ·
Not certain how they'd tell...the fan is running. they did open the side and use a voltage meter at one point...don't know what they were measuring.

then they pulled out the "stethoscope" to check pressure and that's when they said the pressure was equal and the valves were not working (not opening and closing).
 
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