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Acrisoft
24-09-2009, 07:01 PM
A student of mine has the following problem:

He needs to install a ductless mini split system

The manual says he can add length to pipes, but he needs to add pipe length beyond that

My doubt is: Can he increase this length by replacing it for an ductless equipment with more BTU, or he must really quit ductless solution ?


Moises
Brian_UK
24-09-2009, 11:39 PM
If he goes over the maximum length quoted by the manufacturer then there will be no guarantee that he will get the correct duty.
Shibhrac
25-09-2009, 08:11 AM
It is important to always use piping as large as the fitting on the evaporator and on the compressor. If a compressor suction line connection is 5/8 OD, it's advisable to use this size piping. If the liquid line connection is 3/8 OD , use this size. The farther condensing unit to the evaporator the lower performance of the unit is.
Acrisoft
25-09-2009, 12:49 PM
Which is the maximum distance one here was able to reach with ductless split ?

Is BTU capacity an issue when trying to reach higher lengths ?
Shibhrac
25-09-2009, 05:15 PM
Suction line,discharge line, and liquid line sizes. Selection is based on system capacity and length of the pipe including equivalant length.
Thermatech
25-09-2009, 06:40 PM
For example
The manufacture states max interconnect pipe lengh = 50m
Installing contractor installes 60m interconnect pipe.
The cooling performance might be about 5 to 10% reduced.
The compressor life will be shorter than design.
The manufacturer can refuse any warrantee claim as max pipe lenght have been exceeded.

Also some manufactures quote 'equivalent pipe lengh' which means actual lengh + extra allowance for bends.
So taking the same example the manufacturer states 50m max equialent lengh but installer installs 45m of lengh with 30 bends & so the result is an installed eqivalent lengh of more like 60m.
Again no warrantee.
Brian_UK
25-09-2009, 10:45 PM
Which is the maximum distance one here was able to reach with ductless split ?

Is BTU capacity an issue when trying to reach higher lengths ?
RED, we don't know, check with the manufacturers' data.

BLUE, yes, it reduces.