Coolant line diameter source of failure?

[Stansbury]

A repairman says that the cause of failure of our 9 yearold Trane heat pump was incorrect coolant line diameter. We can clearly see that fitting on heat pump is much larger diameter than the tubing connected to it.

Is this plausible as cause of failure ? Is it gross negligence on installers part? Or is there some judgement call as to correct diameter to use?

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details.

We bought our house new 9 years ago in central North Carolina with a heatpump & backup gas furnce downstairs and a heatpump for upstairs. The heat pump has been unreliable since day 1. We've put ~$1,100 into it thus far and it has just been declared dead (dead compressor).

The system was installed by company 'a' and maintained by them for several years. We then switched to company 'b' for a few years. Company 'b' came out to service us after the latest failure and said the compressor is dead. They sent out their expert to quote a new system and he showed us that the old system had undersized diameter coolant line. We can clearly see that the fitting on the heat pump is larger than diameter of tubing and the fitting has been crimped to accommodate smaller tubing.

Is this an obvious sign of faulty installation or is this an acceptable practice?

Thanks,
Stan

[mattison]

Without being there and seeing it I will say this. If the line size is grossly undersized it could lead to premature failure.

What is the linesize vs the unit size?

[lenny56769]

well just to let you know the system comes with larger size in case you need to go up in the line size . because you could be 6ft away to 60ft so it needs to go up or down . but with yours system may i ask how high is one from the other . iam guessing ones up staires and the other is down . well if over 12 ft you would need a trap in line to catch oil does it have one . it would look like a UP SIDE DOWN U before going into the air handler up stairs

[Stansbury]

We have two units. One for upstairs and one for downstairs. The one that recently failed was the downstairs unit. This is the one with the smaller diameter line.

Are you saying that it may be OK for the first floor unit to have a smaller diam line because it is ground-floor unit while the other unit needed a larger diameter line because it must service the second floor unit?

(Actually, the indoor-part of the 2nd floor unit is in the attic above the 2nd floor, so technically it is a 3rd floor unit).

I never noticed if we had a trap for the upstairs unit. I'll check this in the morning.

Thanks for feedback.
Stan

[lenny56769]

what iam saying is that depending on how far apart the two are systems are tells the tech what size line to put in can be small or big its how far away they are . you still could be under size in line . theres lots to look at like how many 90s 45 every 90 takes out six foot of pipe so if you have lots of 90s the tech should of changed size to larger . your book that came with system should tell you what size line to run for the run of pipe being used . i hope this clears things up beter for you