45
System Flushing and Filling
Once the piping is complete, units require final purging and loop
charging. A flush cart pump of at least 1.5 hp is needed to achieve
adequate flow velocity in the loop to purge air and dirt particles
from the loop. Flush the loop in both directions with a high vol
-
ume of water at a high velocity. Follow the steps below to properly
flush the loop:
1. Verify power is off.
2. Fill loop with water from hose through flush cart before using
flush cart pump to ensure an even fill. Do not allow the water
level in the flush cart tank to drop below the pump inlet line
to prevent air from filling the line.
3. Maintain a fluid level in the tank above the return tee to avoid
air entering back into the fluid.
4. Shutting off the return valve that connects into the flush cart
reservoir will allow 50 psig surges to help purge air pockets.
This maintains the pump at 50 psig.
5. To purge, keep the pump at 50 psig until maximum pumping
pressure is reached.
6. Open the return valve to send a pressure surge through the
loop to purge any air pockets in the piping system.
7. A noticeable drop in fluid level will be seen in the flush cart
tank. This is the only indication of air in the loop.
NOTE: If air is purged from the system while using a 10 in.
PVC flush tank, the level drop will only be 1 to 2 in. since liq
-
uids are incompressible. If the level drops more than this,
flushing should continue since air is still being compressed in
the loop. If level is less than 1 to 2 in., reverse the flow.
8. Repeat this procedure until all air is purged.
9. Restore power.
Antifreeze may be added before, during or after the flushing pro
-
cess. However, depending on when it is added in the process, it
can be wasted. Refer to the Antifreeze section on page 45 for more
detail.
Loop static pressure will fluctuate with the seasons. Pressures will
be higher in the winter months than during the warmer months.
This fluctuation is normal and should be considered when
charging the system initially. Run the unit in either heating or cool
-
ing for several minutes to condition the loop to a homogeneous
temperature.
When complete, perform a final flush and pressurize the loop to a
static pressure of 40 to 50 psig for winter months or 15 to 20 psig
for summer months.
After pressurization, be sure to remove the plug from the end of
the loop pump motor(s) to allow trapped air to be discharged and
to ensure the motor housing has been flooded. Be sure the loop
flow center provides adequate flow through the unit by checking
pressure drop across the heat exchanger. Compare the results to
the data in Table 13.
System Flow
FLOW VERIFICATION
The 50PS WSHP units do not include a factory flow switch as
standard. It is recommend to field installed a flow switch or spe
-
cial order a flow switch as factory installed to prevent the com
-
pressor from operating without loop flow.
FLOW REGULATION
Flow regulation can be accomplished by two methods. Most water
control valves have a flow adjustment built into the valve. By
measuring the pressure drop through the unit heat exchanger, the
flow rate can be determined. Adjust the water control valve until
the desired flow rate is achieved. Since the pressure constantly
varies, two pressure gages may be needed in some applications.
See Table 13 for flow rates based on waterside pressure drop.
An alternate method of flow regulation is to install an automatic
flow control valve. These valves feature a removable cartridge
that controls the maximum flow through the valve assembly. Veri
-
fy that the water flow control cartridge matches the application
flow requirement.
ANTIFREEZE
In areas where leaving water temperatures drop below 40°F or
where piping will be routed through areas subject to freezing, anti
-
freeze is needed.
Alcohols and glycols are commonly used as antifreeze agents.
Freeze protection should be maintained to 15°F below the lowest
expected entering loop temperature. For example, if the lowest ex
-
pected entering loop temperature is 30°F, the leaving loop tem
-
perature would be 22 to 25°F. Therefore, the freeze protection
should be at 15°F (30°F - 15°F = 15°F).
NOTE: All alcohols should be pre-mixed and pumped from a res
-
ervoir outside of the building or introduced under water level to
prevent fuming.
IMPORTANT: It is recommended to have a flow switch to pre
-
vent the unit from running if water flow is lost.
Table 13 —
Waterside Pressure Drop
a
NOTE(S):
a. All values based upon pure water at 70°F.
50PS
MODEL
SIZE
WATER FLOW
RATE
(gpm)
WATERSIDE
PRESSURE DROP
(psi)
WATERSIDE
PRESSURE DROP
(ft of H
2
O)
007
1.5
1.3
2.9
2
2.1
4.9
3
4.4
10.1
009
2
1.7
3.9
2.5
2.5
5.8
3.25
4.0
9.3
012
3
1.5
3.4
4
2.5
5.8
5.5
4.5
10.2
015
3
1.4
3.3
4
2.4
5.5
5.5
4.3
9.8
018
4
3.0
7.0
5
4.5
10.4
6.5
7.3
16.7
024
4.5
1.8
4.1
6
3.0
6.9
8
5.1
11.6
030
5.5
0.9
2.1
7
1.4
3.2
10
2.7
6.1
036
7.5
1.4
3.3
10
2.4
5.6
12.5
3.6
8.4
042
8.75
1.9
4.4
10.5
2.7
6.1
13.25
4.0
9.3
048
10.67
2.7
6.3
12
3.4
7.8
14
4.5
10.3
060
12
3.4
7.8
15
5.0
11.7
17.5
6.7
15.4
070
13.5
2.1
4.9
17
3.2
7.4
20.5
4.5
10.4
Summary of Contents for AQUAZONE 50PSH
Page 17: ...17 Fig 15 PSC Motor Single Phase Single Stage WSHP Open Control ...
Page 20: ...20 Fig 18 Constant Torque Motor Single Phase Single Stage WSHP Open Control ...
Page 23: ...23 Fig 21 Constant Airflow Single Phase WSHP Open ...
Page 26: ...26 Fig 24 PSC Motor Three Phase Single Stage WSHP Open ...
Page 29: ...29 Fig 27 Constant Torque Motor Three Phase Single Stage WSHP Open ...
Page 32: ...32 Fig 30 Constant Airflow Motor Three Phase Single Stage WSHP Open ...
