16
FLOW CENTER INSTALLATION AND LOOP FLUSHING MANUAL
Flow Center Initial Startup (cont.)
Pressure/Temperature Plugs
The pressure/temperature plugs (P/T plugs) supplied with the earth loop connector kit are provided as a means of mea-
suring fl ow and temperature. The water fl ow (GPM or L/S) through the unit can be checked by measuring the incoming wa-
ter pressure at the supply water P/T plug and subtracting the leaving water pressure at the return water P/T plug. Comparing
the pressure differential to the pressure drop/fl ow chart on pages 17 and 18 will determine the fl ow rate through the unit.
Example:
An E035 with a 5.4 psi (37.2 kPa) pressure drop would be equivalent to 9 GPM on the chart. More fl ow will not
hurt the performance. However, insuffi cient fl ow can signifi cantly reduce capacity and possibly even damage the heat pump
in extreme conditions.
Notes:
Pressure/temperature gauges should be lubricated with a water-based lubricant and pushed gently into P/T
ports to prevent internal damage to ports. Digital thermometers and pressure gauges needed for the P/T plugs are
available from the manufacturer.
Earth Loop Flow Rate
Units require 2.25-3 GPM (0.14-0.19 L/S) per nominal cooling ton when installed in conjunction with an earth loop. Flow
rates can be determined by measuring the pressure drop across the heat exchanger and comparing it against the pressure
drop table on pages 17 and 18.
Note:
Do not go below 2.25 GPM (0.14 L/S)/ton.
Flow Center Pump Performance
50
60
70
UP26-99 SINGLE
UP26-99 DOUBLE
0
10
20
30
40
0
5
10
15
20
25
30
35
HEA
D
(FEET)
FLOW (GPM)
Figure 13: Performance Pump Curve (FPT & GL Flow Centers)
