RF Unit Installation
5.9.2 Closed-Loop Flushing
WARNING
If equipped with a disconnect switch, de-energize unit by
opening line voltage at disconnect switch or if no disconnect
switch is present, de-energize by shutting OFF line voltage at
the service panel before flushing the system.
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 to purge air and dirt particles from
the loop. Flush the loop in both directions with a high volume of
water at a high velocity.
Follow the steps below to properly flush the loop:
1. Verify that the power is OFF.
2. Fill loop with water from the 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
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.
If air is purged from the system while using a 10 inch PVC flush
tank, the level drop will only be 1 to 2 inches, since liquids 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 inches, 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
process. Re
fer to the Antifreeze section below for more detail.
Loop static pressure will fluctuate with the seasons. Pressures
will be hig
her 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 cooling for several minutes to condition the loop to a
homogeneous temperature.
When complete, perform a final flush and pressurize the loop to a
static press
ure 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 p
ump motor 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.
5.9.3 Antifreeze
In areas where entering loop temperatures drop below 50°F or
where pipi
ng will be routed through areas subject to freezing,
antifreeze is needed. Alcohols and glycols are commonly used as
antifreeze agents. Freeze protection must be maintained to 15°F
below the lowest expected entering loop temperature. For
example, if the lowest expected entering loop temperature is
30°F, the leaving loop temperature would be 22°F to 25°F.
Therefore, the freeze protection must be at 15°F
(30°F-15°F=15°F).
5.10 Electrical—Power Supply Wiring
5.10.1 High-Voltage Wiring
DANGER
Electric Shock!
The system contains an oversize, protective, earthing
(groundin
g) terminal that must be properly connected
otherwise personal injury or death may result.
WARNING
Field wiring must be installed by qualified and trained
personnel.
WARNING
Power to the unit must be within the operating voltage range
indicated on the unit’s nameplate or on the performance data
sheet.
18 |
RF Series Heat Pumps — 8733980022 (2024/12)
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