Instruction Manual

HEATING CYCLE START - UP
CDX-HW CDXX-HW: Installation, Operation, and Maintenance Instructions
9
HEATING CYCLE START - UP
1.
Fill the water heater. Open a hot water faucet while filling the water heater to
vent the air. When the tank is full and all the air is purged, close the faucet.
2.
Ignite the water heater and set the thermostat to 140 degrees.
3.
Purge the air handler's hot water coil and lines.
NOTE: It may require purging several gallons of water so either have a bucket
available or a means of discarding the water.
Close valve number 1 and open valve number 2. (See figure 1) Next, open the
air bleed valve. When all of the air is purged from the lines close valve number
2 and open valve number 1. After all the air is purged from the coil and lines,
open both valve number 1 and 2 and close the air bleed valve.
4.
Switch the room thermostat to the "Heat" position and raise the
temperature setting to a position approximately ten degrees above room
temperature.
WARNING: To prevent damage, the fan coil unit should not be energized for heating
until the hot water coil and all the water lines have been purged of air.
The pump should energize and begin circulating the hot water through the coil.
If the pump is operating properly and the water temperature in the water
heater has reached the set point, then the hot water inlet at the fan coil unit will
be hot. If the pump is running but hot water is not circulating, open the air
bleed valve long enough to purge any remaining air from the hot water lines
and coil. This will allow the pump to begin circulating hot water.
5.
The water heater thermostat should be adjusted so that the water
temperature entering the hot water coil is as close to 140 degrees as
possible with the system energized and operating long enough for all
temperatures to stabilize.
FIGURE 1.
TYPICAL PIPING SCHEMATIC WITH FLOW CONTROL MODULE