Maritime Geothermal TF-45, Installation And Service Manual

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1-Jul-2017 Page 59 001223MAN-05
PUMP DOWN PROCEDURE
STEP 1 Connect the refrigerant recovery unit to the heat pump service ports via a refrigeration charging manifold
and to a recovery tank as per the instructions in the recovery unit manual. If there was a compressor burn
out, the refrigerant cannot be reused and must be disposed of according to local codes.
STEP 2 All water coil heat exchangers must either have full flow or be completely drained of fluid before recovery
begins. Failure to do so can freeze and rupture the heat exchanger, voiding its warranty. Note that this
does not apply to double wall domestic hot water exchangers (desuperheater coils).
STEP 3 Ensure all hose connections are properly purged of air. Start the refrigerant recovery as per the instructions
in the recovery unit manual.
STEP 4 Allow the recovery unit suction pressure to reach a vacuum. Once achieved, close the charging manifold
valves. Shut down, purge and disconnect the recovery unit as per the instructions in its manual. Ensure the
recovery tank valve is closed before disconnecting the hose to it.
STEP 5 Connect a nitrogen tank to the charging manifold and add nitrogen to the heat pump until a positive pres-
sure of 5-10PSIG is reached. This prevents air from being sucked into the unit by the vacuum when the
hoses are disconnected.
STEP 6 The heat pump is now ready for repairs. Always ensure nitrogen is flowing through the system during any
brazing procedures to prevent oxidation inside the pipes. Maritime Geothermal Ltd. recommends replacing
the liquid line filter-dryer any time the refrigeration system has been exposed to the atmosphere.
VACUUM AND CHARGING PROCEDURE
STEP 1 After completion of repairs and nitrogen pressure testing, the refrigeration circuit is ready for vacuuming.
STEP 2 Release the refrigerant circuit pressure and connect the vacuum pump to the charging manifold. Start the
vacuum pump and open the charging manifold valves. Vacuum until the vacuum gauge remains at less
than 500 microns for at least 1 minute with the vacuum pump valve closed.
STEP 3 Close the charging manifold valves then shut off and disconnect the vacuum pump. Place a refrigerant tank
with the proper refrigerant on a scale and connect it to the charging manifold. Purge the hose to the tank.
STEP 4 Weigh in the appropriate amount of refrigerant through the low pressure (suction) service port. Refer to the
label on the unit or the Refrigerant Charge Chart in the MODEL SPECIFIC INFORMATION section for the
proper charge amount.
STEP 5 If the unit will not accept the entire charge, the remainder can be added through the low pressure service
port after the unit has been restarted.
REPLACEMENT PROCEDURE FOR A COMPRESSOR BURN-OUT
STEP 1 Pump down the unit as per the Pump Down Procedure above. Discard the refrigerant according to local
codes.
STEP 2 Replace the compressor. Replace the liquid line filter-dryer.
STEP 3 Vacuum the unit until it remains under 500 microns for several minutes with the vacuum pump valve closed.
STEP 4 Charge the unit with NEW REFRIGERANT and operate it for continuously for 2 hours. Pump down the unit
and replace the filter-dryer. Vacuum the unit until it remains under 500 microns for several minutes with the
vacuum pump valve closed.
STEP 5 Charge the unit (refrigerant can be re-used) and operate it for 2-3 days. Perform an acid test. If it fails,
pump down the unit and replace the filter-dryer.
STEP 6 Charge the unit (refrigerant can be re-used) and operate it for 2 weeks. Perform and acid test, If it fails
pump down the unit and replace the filter-dryer.
STEP 7 Charge the unit a final time. Unit should now be clean and repeated future burn-outs can be avoided.
Repair Procedures