Quantech QTC3040T, Installation Operation & Maintenance

Page: 103 / 190

103
QUANTECH
FORM QTC3-NM1
ISSUE DATE 08/03/2022
6
Commissioning of this unit should only
be carried out by Johnson Controls Au-
thorized personnel.
Commissioning personnel should be thoroughly famil-
iar with the information contained in this literature, in
addition to this section.
Perform the commissioning using the detailed checks
outlined. See Equipment Pre-Startup And Startup
Checklist on page 95
as the commissioning procedure
is carried out.
PREPARATION – POWER OFF
The following basic checks should be made with the
customer power to the unit switched OFF.
Inspection
Inspect unit for installation damage. If found, take ac-
tion and/or repair as appropriate.
Refrigerant Charge
Packaged units are normally shipped as standard with
a full refrigerant operating charge. Check that refrig-
erant pressure is present in both systems and that no
leaks are apparent. If no pressure is present, a leak test
must be undertaken, the leak(s) located and repaired.
Remote systems and units are supplied with a nitrogen
holding charge. These systems must be evacuated with
a suitable vacuum pump/recovery unit as appropriate
to below 500 microns.
Do not liquid charge with static water in the cooler.
Care must also be taken to liquid charge slowly to
avoid excessive thermal stress at the charging point.
Once the vacuum is broken, charge into the condenser
coils with the full operating charge as given in SEC-
TION 5 – TECHNICAL DATA.
ALWAYS keep the water pump running
when vacuuming the system, removing
refrigerating from the system or adding
refrigerant to the system until the process
is completed. If you do NOT, the evapora-
tor may freeze and ruin the system.
Charging after vacuuming - Charge 10%
of the specified amount of refrigerant into
the evaporator. Otherwise, the compressor
is in risk when it starts. Find the system
charges on the unit nameplate.
Do NOT overcharge the system. Otherwise
High Discharge Pressure will frequently
occur.
Charging Refrigerant
If you vacuum the system first, add only the volume of
refrigerant shown on the nameplate.
To charge the refrigerant after vacuuming, complete
the following steps:
1. Start the chilled liquid pump and use the water
valve to ensure that the chilled liquid is circulat-
ing in the evaporator.
2. Place the refrigerant drum on the scale and log the
weight (W
i
).
3. Connect the refrigerant valve to the angle valve in
the liquid line and purge the air from the charging
pipe.
4. Use the angle valve to direct the charge to the high
side only.
5. Find the system charge on the nameplate. Calcu-
late the weight to the high side (W
h
), which is 90%
of the system charge, and calculate W as follows:
W = W
i
- W
h
6. Open the valve on the drum and reverse the drum,
so only liquid is charged into the system.
7. Monitor the reading of the scale and shut off the
valve when the scale reaches W.
8. Close the angle valve and switch the charging
pipe from angle valve to Schrader valve between
the evaporator and EEV/TXV.
9. Purge the air from the charging pipe.
10. Open the valve on the drum to charge the remain-
ing 10% of the system charge into the low side.
SECTION 6 – COMMISSIONING