Carrier 50YFV Installation, Operation And Maintenance Instructions page 17

R e s i d e n t i a l D i g i t a l P a c k a g e d U n i t s G T- P B S e r i e s - 6 0 H z P u r o n
Multiple Units with Internal Modulating Valves and
Central Pump
This is an application where multiple units are used in
conjunction with a central, variable speed pump. In this case,
units with closed loop modulating valves are used (do not
use open loop modulating valves on a closed loop system).
External fl ushing valves are required. This application is for
larger systems, including commercial.
Figure 16c: Multiple Units with Internal Modulating Valves and Central Pump
Size for Heat Pump
'A' Flow
Heat Pump
Water Out
Water In
Before fl ushing, the installer should manually open all
modulating valves as detailed in Closed Loop – External
Central Pumping section of this manual. Next, fl ush the
ground loop. The installer should close a pump isolation
valve and open the ground loop shut-off valve to prevent fl ow
through the indoor loop while fl ushing the ground loop.
Once the ground loop is fl ushed, close the ground loop
shut-off valve and open the pump isolation valve to fl ush
the units and indoor piping. Once the system is fl ushed
remember to return the modulating valves to their normal
operating position.
Size for 'A' + 'B' Flow
Heat Pump
Size for
Heat Pump
'B' Flow
Water Out
Water In
Multiple Unit Piping and Flushing
Size for 'A' + 'B' + 'C' Flow
Heat Pump
Isolation
Size for
Heat Pump
'C' Flow
Water Out
Water In
R e v : 4 A p r i l , 1 4
Ground Loop
Shut-Off Valve
To Ground
Exp
Pump
Flush
Tank
Valve
Pump
Valves
®
Loop
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