View Full Version : ??? Line set sizing
10-20-2007, 07:54 PM
I am replacing a old 10 ton ( obviously over sized) straight air split system with a 5 ton heat pump The condenser is 12 feet above the evaporator and line set is about 65 feet long. This thing was installed years ago but appears to be professionally installed (except for the oversizing). Line set has 2 traps for oil issues but does have multiple 90 degree angles. The line set is very large (diameter) compared to what I am used to working on. Suction line is 1 1/2 inch and liquid is 1/2. The new 5 ton takes 1 1/8 suction for 50 + feet and 3/8 for 50+.
Can someone tell me if it will be alright to use large existing line set?
10-20-2007, 08:16 PM
to maintain proper refrigerant velosity to cool and lubricate the compressor , you will need to consult a piping chart or table. If you've never done this you really should get someone with that experience to do it
10-20-2007, 09:01 PM
Heat pump liquid size must be kept to manufacturer's recommendations. All the 5 tons I know about you must keep to the 3/8". If you use that 1/2" you'll have liquid slugging into the compressor during the heating mode and you'll be replacing compressors like crazy.
Vapor line is very questionable, but the liquid line is the key.
10-20-2007, 09:18 PM
10-20-2007, 09:27 PM
Thanks dawgtchrr. Very good point.
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