16
G e o t h e r m a l H e a t P u m p S y s t e m s
P R E L I M I N A RY
Tranquility
®
30 Digital (TE) Series IOM - 60Hz HFC-410A
R e v. : 3 A u g . , 2 0 1 2 B
Multiple Unit Piping and Flushing
Water Out
Water In
Heat Pump
B
Water Out
Water In
Heat Pump
A
To Ground
Loop
Water Out
Water In
Heat Pump
C
Indoor Loop
Shut-Off Valve
Ground Loop
Shut-Off Valve
Flush
Valve
Size for Heat Pump
‘A’ Flow
Size for ‘A’ + ‘B’ Flow
Size for ‘A’ + ‘B’ + ‘C’ Flow
Size for
Heat Pump
‘C’ Flow
Size for
Heat Pump
‘B’ Flow
Water Out
Water In
Heat Pump
B
Water Out
Water In
Heat Pump
A
To Ground
Loop
Size for Heat Pump
‘A’ Flow
Size for Heat Pump
‘B’ Flow
Size for ‘A’ + ‘B’ Flow
Figure x: Multiple Units with Internal Flow Controllers
Figure x: Multiple Units with Internal Flow Controllers and External Flushing Valves
Multiple Units with Internal Flow Controllers and External Flushing Valves
When the number of units or
fl
ushing requirements reaches a point where it
is no longer feasible to
fl
ush through the internal valves (generally systems of
more than 12 tons depending on loop design), external
fl
ushing valves should
be installed. In this case, three-way
fl
ushing valves should be used or additional
isolation valves must be installed to be able to isolate the loop during
fl
ushing.
First,
fl
ush the ground loop. The installer should close the indoor loop shut-
off valve (or the internal
fl
ushing valves in all units) 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 indoor loop valve(s) to
fl
ush the units and indoor piping.
Remember that there is an internal check valve in the variable speed pump
and that backward
fl
ow the unit is not possible.
