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15 year old Mini split systems. If replacing the CU, what about the indoor unit?

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In my mind it make sense to replace the unit with any major repair.  around here the service call is $125 and any minor repair would be an additional $100-200 and that would represent what percentage of the total replacement cost of entire component.  When it gets to 33% - I would replace. 


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I'd absolutely replace the entire system upon failure of the compressor. The reason is very simple: R 22 is now phased out. Prices for this refrigerant is now more than 10 times higher than it was before the phase-out began.

Edited by Marc
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Bill, do you really have experience with a number of mini-splits installed circa 2000? I am not rebutting you, I am actually really hopeful that you do. I hope that you know of a facility with tons of them. 

The reason for the whole question is because there are so few people who have real experience with these things for 15+ years. In the USA, there is really no-one.

We all know instinctively how to handle normal split systems. We are slowly getting to a new time where we will have waves of these which are already R410a with worn out compressors. An old furnace would last 40+ years. You only replaced it if it was 30 to 40+ years old and the outdoor unit compressor died (before R410a required replacements). They are like old cars, replace the guts and keep driving. 

We have a new beast here. If we do not replace the indoor unit with the outdoor unit, will the indoor unit last another 15 years until the 2nd outdoor unit compressor fails from age?

And then we get into multi-splits with one outdoor unit and 4 indoor units to further muddy the water.  

Edited by MPdesign
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I don't keep a count, but I'm sure I've checked thousands.  They're extensively used in the types of buildings I inspect.  Office buildings, (including every server room ever) retail, restaurants, old buildings with multiple additions and historic buildings that ducted installations would cause irreversible damage.  I also have a friend who owns a top HVAC firm for almost 40 years that was one of the first to import ductless systems.

The estimated 20 year lifespan is conservative.  Some have made it to near 30.  These were all manufactured in Japan.  Now there's been a change.  Over the last 4 or 5 years, the systems have all been manufactured in Korea or Taiwan (even Mitsubishi).  There is no way to decipher the age from the serial numbers on these recent systems.  I also don't yet know the life expectancy of the new heat pump systems with inverters.

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