Installation Guide for NHPA Split-System Heat Pumps
8
b.
Provide a heat sink at the service valve such as wrapping
a wet rag around it, to prevent damage during the brazing
operation
c
. Braze the liquid line to the service valve. Allow the nitrogen
to keep flowing when brazing the refrigerant line until all
brazed joints are completed.
d
. Carefully remove the rubber plugs from the evaporator
liquid and vapor connections. Use caution as the
evaporator is pressurized.
e.
Braze the liquid line to the evaporator liquid connection
f.
Braze the vapor line to the evaporator vapor connection
g.
Provide a heat sink to the vapor line service valve of the
heat pump.
h.
Braze the vapor line to the service valve
i.
When tubing installation is completed, seal openings
around tubing where tubing enters the unit cabinet.
j.
Standard refrigeration piping practices must be employed
when installing traps. When installing the condenser
below the evaporator, the suction line must be trapped
with an inverted trap the height of the evaporator coil.
Consult the factory when total equivalent length of
refrigerant lines exceeds 50 ft.
Leak Checking
Leak checking of refrigerant line braze joints and evaporator
unit using dry nitrogen.
1.
Install service port cap of the vapor line service valve (cap was
removed for brazing operations).
2.
Connect dry nitrogen source to the service port of the liquid
line service valve. Pressurize refrigerant lines and indoor coil to
approximately 100 PSIG.
3.
Check for leaks using a liquid soap solution. If any leaks are
located, purge the nitrogen, repair the leak(s) and repeat the leak
check procedure.
Leak checking of refrigerant line braze joints and evaporator
unit using R410a refrigerant.
1.
Connect R410a source to the service port of the liquid line
service valve. Use of a manifold gauge set will facilitate connecting
and disconnecting of the refrigerant source for leak checking.
Pressurize refrigerant lines and indoor coil with refrigerant gas.
2.
Leak check with an electronic leak detector or liquid soap
solution. If any leaks are detected, use a refrigerant recovery
system to remove the refrigerant. Repair the leak(s) and repeat
the leak check procedure.
Apply liquid soap solution to check for leaks
or leak check with an
electric leak detector
Bubbles forming in the liquid soap solution indicates a leak.
