Heat Controller DMH18DB-1, Service Manual

Page: 33 / 70

Service Manual 33
Charging
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Each outdoor unit is factory charged (nameplate charge) for the evaporator as well as a 7.5m(25ft) line set for
each indoor line.
Any time total line set is used either shorter or longer then the nominal 15m(50ft) line set length the refrigerant
charge has to be adjusted.
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Whether the line set is made shorter or longer you must adjust the charge based on how many ft of tubing are
either added or removed based on 20g/m(0.22oz/ft) of R-410A per meter(foot).
Example:
A 75ft line set is used for dual - zone 25 additional ft X 0.22 ounces per foot= add 5.5 ounces of R-
410A
Important:(Unit is critically charge)
If you are ever uncertain of the unit charge, reclaim, evacuate and weigh in the correct charge using the unit name-
plate charge adjusting for line sets longer or shorter than 7.5m(25ft) for each indoor unit.
18k 30m(100ft) 15m(50ft) 5m(16ft) 7.5m(25ft) 7.5m(25ft) 20g/m(0.22oz/ft)
Capacity (Btu/h)
Max total length
of all pipes
(A+B)
Max length of
each pipe (A/B)
Min length of
each pipe (A/B)
Max Elevation
between each indoor
unit and outdoor unit
(h1)
Max elevation
between indoor
units (h2)
Additional
Refrigerant
Charging