ARTC-SVX001B-EN
B–1
Appendix B.
Tank and Pump Module
Tank and Pump
Components
A tank and pump module typically contains dual lead/
lag pumps and an expansion tank. If the chiller fluid is
glycol, there will be a glycol feeder consisting of a
vented reservoir and charging pump. The charging
pump maintains the system pressure at 12 psi by
sensing the pump suction pressure.
A sealed stainless steel storage tank can also be
provided in lieu of an expansion tank. With a
pressurized tank there is no requirement for an
additional expansion tank as it uses trapped air in the
fluid system to allow system expansion. An air
separator is not recommended in a fluid system with a
pressurized tank because without the trapped air, the
system expansion characteristics of the tank could not
be exploited. The sealed tank also contains a vacuum
vent to protect the tank from imploding.
Dual lead/lag pumps, each with 100% pumping
capacity, are provided in each tank and pump module.
If the lead pump fails to operate, the lag pump activates
and an alarm signal is generated on the
microprocessor controller indicating primary pump
failure. Under normal system operation, each pump
rotates as the lead pump every 168 hours of system
operation. Pump motors can be equipped with variable
frequency drives (VFDs) for variable flow operation. For
the system to operate with variable flow, each heat
recovery chiller module must have electronic
modulating valves.
Switches inside the pump module control panel start
each pump. Ensure that the each pump rotates
clockwise and the pressure drop across the system is
as expected.
Figure 32.
Typical tank and pump module layout
