OMM TGZ-1 TGZ 040A through TGZ 190A 19
Weekend or Temporary Shutdown
Move pumpdown switch(es) PS1 and PS2 to the “manual pumpdown” position.
Note: With the unit in this condition, it is capable of limited pumpdown. To defeat this mode of
operation, simply move control system switch S1 to the “off” position.
!
CAUTION
The compressors must complete pump down before the water flow to the unit is interrupted to
avoid freeze-up damage in the evaporator.
Start-up after Temporary Shutdown
1. Start the source water and hot water flow through the unit.
2. With the control system switch S1 in the “on” position, move the pumpdown switch(es) PS1
and PS2 to the “auto pumpdown” position.
3. Observe the unit operation for a short time, noting unusual sounds or cycling of compressors.
Extended Shutdown
1. Close the manual liquid line shutoff valves.
2. After the compressors have pumped down, stop or bypass the source water and hot water flow.
3. Turn off all power to the unit.
4. Move the control service switch S1 to the “off” position.
5. Close the suction and discharge shutoff valves on the compressor(s) and the liquid outlet
valves at the condenser(s) or receiver(s).
6. Tag all opened disconnect switches to warn against start-up before opening the compressor
suction and discharge valves.
7. Drain all water from the unit evaporator and chilled water piping if the unit is to be shut down
during the winter and exposed to below freezing temperatures. Do not leave the vessels or
piping open to the atmosphere over the shutdown period.
Start-up after Extended Shutdown
1. Inspect all equipment to see that it is in satisfactory operating condition.
2. Backseat the compressor suction and discharge valves. Always replace valve seal caps.
3. Open the manual liquid line shutoff valves.
4. Check circuit breakers. They must be in the “off” position.
5. Check to see that the pumpdown switches PS1 and PS2 are in the “manual shutdown” position
and the control system switch S1 is in the “off” position.
6. Throw the main power and control circuit disconnects to the “on” position.
7. Allow the crankcase heaters to operate for at least 12 hours prior to start-up.
8. Start the source water flow and purge the water piping as well as the evaporator in the unit.
9. Start the auxiliary equipment for the installation by turning on the time clock, ambient
thermostat and/or remote on/off switch.
10. Adjust the setpoint on the MicroTech controller to the desired hot water temperature.
11. Check resets of all equipment protection controls.
12. Switch the unit circuit breakers to “on.”
13. Start the system by pushing the system switch S1 to “on.”
!
CAUTION
Most relays and terminals in the control center are powered when S1 is closed and the
control circuit disconnect is on. Do not close S1 until ready for start-up or serious
equipment damage can occur.
14. Place pumpdown switch(es) PS1 and PS2 to the “auto pumpdown” position for restart and
normal operation.
15. After running the unit for a short time, check the oil level in each compressor crankcase
and for flashing in the refrigerant sightglass (see Maintenance section).
To Next Page
Loading...
Need help?
General