QUANTECH
144
FORM QWC4-NM1 (221)
ISSUE DATE: 02/28/2021
SECTION 7 - MAINTENANCE
Mechanical Tube Cleaning Procedure
1. Drain the water from the condenser.
2. Remove the waterboxes from both ends of the
condenser with proper lifting equipment. Use cau-
tion not to damage the threads on the mounting
studs that are welded to the tube sheet.
3. Select a tube cleaning brush for 5/8 in. ID copper
condenser tubes. If tubes other than those with 5/8
in. ID are used, select a tube cleaning brush that
is made for the tube size. Generally, brushes made
of hard plastic or brass bristled wires are preferred
for cleaning copper tubes. DO NOT use a steel
bristle brush.
4. Attach the tube cleaning brush to the end of a
cleaning machine or rod.
5. Flush the condenser with clean water to remove
the debris.
6. Replace the waterbox gasket with a new gasket,
and reassemble the waterbox onto the condenser.
COMPRESSOR MAINTENANCE
To perform maintenance on the compressor assem-
bly, complete the following:
1. Check the operation of the oil return system and
change the dehydrator.
2.
Check and change the oil, and oil filters.
3. Check the operation of the oil heater.
4. Observe the operation of the compressor.
Internal wearing of compressor parts could be a seri-
ous problem caused by improper lubrication, brought
about by restricted oil lines, passages, or dirty oil fil-
ters. If the unit is shutting down on low oil pressure
(LOP), change the oil filter element and examine it for
foreign material. If foreign material is noticeable and
the same conditions continue to stop the unit operation
after a new filter element is installed, contact a Quan-
tech Field Service Office.
ELECTRICAL CONTROLS
For information covering the control center opera-
in this manual,
and
Field Connections and Control Wiring for QWC4
Chiller (Form QWC4-PW2)
.
Checking VSD Coolant Level
Never run the coolant pump without cool-
ant! Running the coolant pump without
coolant may damage the pump seals.
Always fill the system with approved
Quantech
coolant to avoid damage to the
pump seals and the chiller.
The chiller is shipped with a 50/50 mix of Propylene
Glycol and Quantech Corrosion Inhibitors. This type
of coolant is being used to protect the cooling loop
from damage due to freezing conditions during the
shipping process. This coolant mixture does not have
the thermodynamic properties required by the variable
speed drive, and must be removed. Drain the coolant
from the variable speed drive.
This 50/50 mixture must be drained and replaced with
Quantech Corrosion Inhibitor as specified below.
1. Drain the coolant from the variable speed drive.
2. Fill the coolant loop using Quantech’s Corrosion
Inhibitor, part number 013-04129-000. Pour the
solution into the top of the header pipe until the
level is within a 1/2 inch of the top.
3. Then manually run the pump to remove pockets
of air. Observe the level in the fill-pipe, and more
coolant as necessary to bring the level back to ap-
prox.. 1/2 from the top of the pipe.
4. Continue to run the pump manually for 15 min-
utes, adding more coolant as needed. Then rein-
stall the pipe plug in the header pipe using teflon
tape to assure coolant does not evaporate through
the pipe threads. Do not wrap the threads with
more than 2 wraps of Teflon tape. Too much tape
can cause the fill pipe to crack.
Summary of Contents for QWC4
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