Comfort-Aire HWW120 - Manual (Page 24)

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Installation & Operation WATER-TO-WATER (HWW) SERIES Heat Controller, Inc.
Piping Systems Cleaning & Flushing
Cleaning and flushing of the WLHP piping system is the
single most important step to ensure proper start-up
and continued efficient operation of the system.
Follow the instructions below to properly clean and flush the
system:
1. Verify electrical power to the unit is disconnected.
2. Install the system with the supply hose connected
directly to the return riser valve. Use a single length of
flexible hose.
3. Open all air vents. Fill the system with the water. DO
NOT allow system to overflow. Bleed all air from the
system. Pressurize and check the system for leaks and
repair appropriately.
4. Verify all strainers are in place. Start the pumps, and
systematically check each vent to ensure all air is bled
from the system.
5. Verify make-up water is available. Adjust make-up water
appropriately to replace the air which was bled from
the system. Check and adjust the water/air level in the
expansion tank.
6. Set the boiler to raise the loop temperature to approxi-
mately 85°F [29°C]. Open the a drain at the lowest point
in the system. Adjust the make-up water replacement
rate to equal the rate of bleed.
7. Refill the system and add trisodium phosphate in a
proportion of approximately one pound per 150 gal-
lons [1/2 kg per 750 L] of water (or other equivalent
approved cleaning agent). Reset the boiler to raise the
loop temperature to about 100°F [38°C]. Circulate the
solution for a minimum of 8 to 24 hours. At the end of
this period, shut off the circulating pump and drain the
solution. Repeat system cleaning if desired.
8. When the cleaning process is complete, remove the
short-circuited hoses. Reconnect the hoses to the
proper supply, and return connections to each of the
units. Refill the system and bleed off all air.
9. Test the system pH with litmus paper. The system water
should be slightly alkaline (pH 7.5-8.5). Add chemicals,
as appropriate, to maintain acidity levels.
10. When the system is successfully cleaned, flushed,
refilled and bled, check the main system panels, safety
cutouts and alarms. Set the controls to properly main-
tain loop temperatures.
� CAUTION! �
To avoid possible damage to a plastic (PVC) piping sys-
tem, do not allow temperatures to exceed 110°F [43°C].
� CAUTION! �
DO NOT use 'stop leak' or any similar chemical agent
in this system. Addition of these chemicals to the loop
water will foul the system and inhibit unit operation.