Heating, Air Conditioning, Fridge, HVAC/r22 versus 410a

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QUESTION: My condo will be getting a new roof.  My air-conditioner (R22 & Lennox)is working but is 30 years old so I had always planned on replacing it after the new roof. Now, we are being told that residents with older a/c units will have to pay $250 to have them use a crane to lift the units and roof under them.  The newer units are on (better?) platforms so they will not roof under them, just seal around each platform.  I have a feeling the older units will somehow not be returned to working condition and we will be "offered" to have their (the roofer's) HVAC guy replace the unit (& he doesn't install Lennox, my current brand...30 years/long lasting; he uses Carrier).  They will not promise that any unit will work after being lifted. Should I risk it and get the new unit now?  Is it that easy to do something that would damage a new air conditioner? I hesitate to get a new unit now because during 2 previous roofings there has always been at least one unit that wasn't returned to working order. Then it's a big mess.  The HOA board has already signed the roofing contract.  Also, I only use the a/c during ninty degree or warmer heat waves.  I was told by one contractor that the R22 units work better than the 410a when you have temps over 100 degrees. Is that true? Another company disagrees.

ANSWER: Sorry for the delay in answering.  This site is not sending me notices I have questions in my cue.

I am not sure where you live, but where I live there are building codes that require the units be a certain height off the roof.  This allows the roof work to be completed without disturbing the unit.  The code has changed here over the years.  The units could be installed on sleepers, but now have to be on stands.  Generally speaking the height issue is for split systems.  Package units sit on a curb and the roof is sealed around the curb.  

Since you live in an HOA, you need to refer to those documents to see what, if any, restrictions are there as far as brand etc.  You should DEMAND pictures of your unit before it is moved.  That will also prove that it is not damaged.  If taken proper care, the unit should work just the same as before it was picked up.   It might even be worth while to get a price from another contractor about replacing the system before the roof work.  The new unit would then be installed on the proper stand.  I would not think that you would be forced to use the HVAC contractor working with the roofer for a new unit. That HVAC contractor installs Carrier because he is likely a Carrier dealer and gets better pricing.  I do not know of too many contractors that will loose a sale over brand.  Even the manufacture's own service departments will work on other brands to make a buck when they are able to.     

I would think it is a good time for a new unit.  Your unit is not very efficient and has lasted nearly double the life expectancy of a system. Both R-22 and R-410a can struggle when it gets really hot outside. The unit on the roof does not help it in any way.  Unfortunately, new systems are using R-410a.  

Craig

---------- FOLLOW-UP ----------

QUESTION: I read there is now a new r22 (r22a?) that can be used that addresses the environmental issues.  If my refrigerant lines cannot be replaced, should I forgo the 410a & stick with a compatible r22system?

ANSWER: Once again, this service has failed to let me know...

The replacement refrigerants for R-22 are for existing systems only.  There are "dry" systems that can be purchased to allow for the continued use of R-22 or equivalent.  They do have flushes out there to clean out the existing line set so long as it is sized correctly.  You are going to be far better off replacing the system completely, unless there is just no other choice in the matter.

---------- FOLLOW-UP ----------

QUESTION: Thank you for your advice. Going by what the pros tell me, replacing the copper lines is not an option because they run through the unit above me on the 3rd floor.  What size lines are the "proper size" for the switch to r410?  Also, my lines are 30 years old.  Won't the higher pressure be risky?

Answer
The copper lines should be able to handle the pressure.  As far as I know, the wall thickness of the copper tube has not changed.

The size of the copper lines vary with several factors. It is not possible for me to tell you what size they need to be.  

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Craig HVAC Expert

Expertise

I have been in the HVAC field for the past 18 years. I can help with most HVAC questions. I work on commerical buildings for the most part, and have yet to find anything I could not troubleshoot and repair, when repairable. I work on small 1 ton units to a 2500 ton chiller. Troubleshoot air flow, elect, and control problems. I attend regular classes to keep up with the latest and greatest.

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I work on commerical sites, hospitals, gov't buildings. I can troubleshoot just about anything in the HVAC business.

Education/Credentials
5 years trade school, VFD training classes, Liebert factory training, some York and Trane factory training.

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