Refrigerant Lines; General Information - Bosch CE SPLIT series Installation And Maintenance Manual

refrigerant lines

Pressure / temperature ports are recommended in
both the supply and return lines for system flow
balancing. The water flow can be accurately set by
measuring the water-to-refrigerant heat exchangers
water side pressure drop.
The discharge water from the heat pump is not
contaminated in any manner and can be disposed of
in various ways depending on local codes (i.e.
discharge well, dry well, storm sewer, drain field,
stream, pond, etc.)
rEfrIGEranT lInES
The installation of the copper refrigerant tubing
must be done with care to obtain reliable, trouble-
free operation. This installation should only be
performed by qualified refrigeration service and
installation personnel.
Refrigerant lines generally can and should be routed
and supported so as to prevent the transmission of
vibrations into the building structure. Experience
and good design practice dictate 75 feet as the
maximum practical length for interconnecting
refrigerant lines in split system heat pumps without
special considerations. Beyond 75 feet, system
losses become substantial and the total refrigerant
charge required can compromise the reliability and
design life of the equipment.
Refrigerant lines should be sized in accordance with
Table 3 in the following instructions. Copper tubing
should be clean and free of moisture and dirt or
debris. The suction and liquid lines MUST be
insulated with at least 3/8" wall, closed-cell foam
rubber insulation or the equivalent.

GEnEral InforMaTIon

(rEfrIGEranT lInES)
1. Pressure drop (friction losses) in refrigerant
suction lines reduces system capacity and
increases power consumption by as much as 2%
or more, depending on the line length, number
of bends, etc. Pressure drop in liquid lines
affects system performance to a lesser degree,
provided that a solid column of liquid (no flash
gas) is being delivered to the refrigerant
metering device, and that the liquid pressure at
the refrigerant metering device is sufficient to
produce the required refrigerant flow.
Revised 03-11 Subject to change without prior notice
2. Oil is continually being circulated with the
refrigerant so, oil return to the compressor is
always a consideration in line sizing. Suction
lines on split system heat pumps are also hot gas
lines in the heating mode, but are treated as
suction lines for sizing purposes. If the
recommended suction lines sizes are used, there
should be no problem with oil return.
3. Vertical lines should be kept to a minimum.
Vertical liquid lines will have a vertical liquid lift
in either heating or cooling, and the weight of
the liquid head is added to the friction loss to
arrive at the total line pressure drop.
4. Wherever possible, the air handler should be
installed at a higher elevation than the
condensing section to aid with oil return to the
compressor.
lInEar VS. EQuIValEnT lInE lEnGTH
lInEar lInE lEnGTH – is the actual measured
length of the line including bends. This issued to
calculate the additional refrigerant charge that must
be added to the system (See Table 3 and examples).
EQuIValEnT lInE lEnGTH – is the combination of
the actual lengths of all straight runs and the
equivalent length of all bends valves and fittings in a
particular line. The equivalent length of a bend, valve
or fitting is equal to the length of a straight tube of the
same diameter having the same pressure drop as the
particular valve or fitting. The ASHRAE Fundamentals
Handbook provides tables for determining the
equivalent length of various bends, valves and fittings.
Liquid and suction line sizes as shown in Table 3 are
based on Equivalent Line Length.
ConnECTInG rEfrIGEranT lInES
• Use only ACR grade copper tubing and keep ends
sealed until joints are made.
• For best performance, select routing of refrigerant
lines for minimum distance and fewest number of
bends.
• Size lines in accordance with Table 3.
• Cut crimped ends off the air handler suction and
liquid lines. Connect and braze lines to the air
handler.
6 720 220 049
CE Split Series 13