Comfort-Aire HBH Series 1/2 to 5 Ton - Manual (Page 31)

Heat Controller, Inc. HBH/V COMPACT IOM Instructions
Piping System Cleaning and Flushing
Cleaning and flushing the WLHP piping system is the
single most important step to insure proper start-up and
continued efficient operation of the system.
Follow the instructions below to properly clean and flush
the system:
1. Insure that 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 water. DO
NOT allow system to overflow. Bleed all air from the
system. Pressurize and check the system for leaks
and repair as appropriate.
4. Verify that all strainers are in place (Heat Controller
recommends a strainer with a #20 stainless steel wire
mesh). Start the pumps, and systematically check each
vent to ensure that all air is bled from the system.
5. Verify that make-up water is available. Adjust make-
up water as required 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
approximately 86°F [30°C]. Open 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
gallons [1/2 kg per 750 l] of water (or other equivalent
approved cleaning agent). Reset the boiler to raise
the loop temperature to 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 the 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 in the range of pH 6.0 - 8.5 (see table
3). Add chemicals, as appropriate to maintain neutral
pH 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
maintain loop temperatures.
DO NOT use “Stop Leak” or similar chemical agent in this
system. Addition of chemicals of this type to the loop water
will foul the heat exchanger and inhibit unit operation.
NOTE: Heat Controller strongly recommends all piping
connections, both internal and external to the unit, be
pressure tested by an appropriate method prior to any
finishing of the interior space or before access to all
connections is limited. Test pressure may not exceed
the maximum allowable pressure for the unit and all
components within the water system. Heat Controller will
not be responsible or liable for damages from water leaks
due to inadequate or lack of a pressurized leak test, or
damages caused by exceeding the maximum pressure
rating during installation.
Piping System Cleaning and Flushing