Installation Guide for NHPA Split-System Heat Pumps
12
Ounces & Pounds of R410A required for line sets
Weight
Tubing Size
10’
15’
20’
25’
30’
35’
40’
45’
50’
Ounces
3/8” - 3/4”
0
3.5
7
10.5
14
17.5
21
24.5
28
Pounds
3/8” - 3/4”
0
0.21875 0.4375 0.65625
0.875
1.09375 1.3125 1.53125
1.75
Refrigerant Charging
The heat pump comes from the factory pre-charged
recommended evaporator coil, and the 10 feet of refrigerant
lines. If the actual line length is greater or less than 10 feet, add
or remove refrigerant at the rate of 0.6 ounces per foot.
If the heat pump charge was lost for any reason, add factory
refrigerant charge listed on heat pump data plate, plus
adjustments described above. If the unit is operating during
charge adjustment, the access panel must be in place to prevent
high head pressure which would shut down the unit.
Note: The 10ft. of tubing included in the nameplate charge
has been accounted for, use actual linear length with the table
below.
When replacing a R-22 system, it is recommended, that new
Line Sets be used. If the old line sets are to be used, they MUST
be flushed with a commercial flushing agent. R410A refrigerant
oil, is not compatible with R-22 oil. The indoor coil MUST be
replaced and a TXV MUST be used.
Important: The outdoor unit is fully charged
at the factory for the recommended model
of indoor unit. With other models of indoor
units the charge must be adjusted. Be sure
both service valves are closed during tubing
installation and leak checking to avoid loss of
charge. A Bi-Flow liquid line filter drier must be
installed (SPORLAN #HPC103-S or similar).
!
CAUTION
Low Suction Pressure Operation! Compressor Damage!
Do not
operate with a restricted suction.
Do not
operate with the low-pressure cut-out bridged. Do not operate compressor
without enough system charge to maintain at least 0.5 bar suction pressure.
Allowing pressure to drop below 0.5 bar for
more than a few seconds may overheat scrolls and cause early drive bearing damage.
The system should be liquid-charged through the liquid-receiver shut-off valve or through a valve in the liquid line. The
use of a filter drier in the charging line is highly recommended. Because R410A and R407C are blends and scrolls have
discharge check valves, systems should be liquid-charged on both high and low sides simultaneously to ensure a positive
refrigerant pressure is present in the compressor before it runs. The majority of the charge should be placed in the high
side of the system to prevent bearing washout during first-time start on the assembly line.
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1. Connect the charging cylinder to the manifold gauge set. Open
the charging cylinder valve and bleed air out of the charging hose
at the manifold gauge set connection.
2. Tighten the manifold gauge set charging connection. Open the
main manifold gauge set valve and introduce refrigerant into the
system.
NOTE
: Oil charge is polyester 32bce.
3. When the correct refrigerant charge level is obtained, remove
the manifold gauge set.
4. Replace the gauge port caps.
Permanently stamp the unit data plate with the total amount of
refrigerant in the system. For coils equipped with TXV’s charge
to sub-cooling, 15-19° at service valve; superheat, 12-18° at
service valve.
Note: All information based on the following
Air Flow Chart. Recommended superheat is
12 - 18° at service valve. Superheat temperature
measurements should be taken within 3 feet of
the compressor suction line connection.
