...and all may be over 30 years old and seem to use R-22 refrigerant.

Sorry for how long this is, there's a lot to explain.

Phoenix metro area, outside temps reach about 115° every summer and have peaked at 120°. House is about 3300sqft (part basement) has two units, detached workshop is about 1000sqft and has one unit. I'm reasonably certain that all are electrically-powered split-system heatpumps. Workshop unit doesn't have any aux heating, I don't know if the house does or not.

The smaller unit on the house, about 2 ton, isn't running its compressor. Kitchen, dining room, family room, and a storage room are the only areas served by this unit, less than 1/3 of the house. We didn't even notice for some time, thinking the hotter than expected kitchen was a result of the range being used for cooking dinner and the thermostat going into Daylight Savings Time. Today I realized that it was still not cold even though it should have been running for the better part of two hours. I confirmed that only the fan was running outside, and that the compressor was not engaging. I put a manifold gauge set on and got about 145psi on both high and low sides, no variance side to side. I've worked on auto air conditioning systems fairly extensively, so I'm fairly certain that my compressor-no-start diagnosis is fairly correct.

If it turns out to be just a bad start/run capacitor then I'll just replace it, but if the compressor motor itself is bad then I'm considering some more drastic changes.

The compressor unit that has failed is located on the ground between the house and the workshop, and is supplying the air handler on the West end of the house, about 25' in from the compressor. On the other end of the house is another compressor, supplying the East end air handler, which is also about 25' in. The two air handlers are in-line with each other and are 30' to 40' apart, with a maintenance crawlspace in the attic above them that passes right over both compartments. The compressor for the workshop is on the northwest corner of the workshop, and the air handler is just on the other side in the northwest corner inside. The workshop's air handler sits 45'-50' from that failed compressor for the west end of the house.

What I'm wondering, is if there's a system that allows one compressor to supply refrigerant to more than one air handler similar to automotive air conditioning in vans where there are two evaporator cores. If I replaced multiple distinct systems with one I could do the following:
  • Replace both house systems with one system. Place the compressor on the East end, run refrigerant lines through crawlspace to both air handlers, one that's about 25' away, the other about 65' away. Run control cabling along same path, change thermostats, change air handlers. Delete having a compressor located between the house and workshop that supplies the house. Continue to drain condensate through existing piping from air handlers.
  • Replace all three systems, run lines, 25', 65', and 45' to the house, house, and workshop air handlers, or else relocate workshop air handler (it's just exposed in the corner) to make lengths work better. Delete compressors for both the East side of the house and the workshop, run new control cabling and new thermostats.


Are there any systems compatible with this? If not that's okay, and I know that there probably are some realistic lengths for refrigerant lines that I'm butting up against. At this point, while cost is a consideration, I am in the position of budgeting for a long term to make it happen.

Thanks.