Water Pipe Hole Size And Location; Pipe Gradient And Air Venting Valve (Outlet Hot Water Pipe) - Mitsubishi Electric QAHV Série Manuel D'installation & D'instructions

[3] Water Pipe Hole Size and Location

Water inlet
(Bronze Rc3/4, female screw)

[4] Pipe gradient and air venting valve (Outlet hot water pipe)

During the hot water storage operation, the air dissolved in the water is discharged in the form of bubbling from the
outlet hot water pipe to quickly raise low-temperature water to the required temperature. When the air accumulates in
the pipe, the resistance of the water circuit will increase and the flow rate will extremely decrease. Because of this, an
installation of automatic air venting valves is required when there is a pipe that slopes down in the outlet hot water
pipe.
Install the pipe with an upward gradient of 1/200 or more toward the air vent to prevent air accumulation in the pipe.
Also, install air venting valves to the places where air can accumulate. The installation example is shown below.
Note:
• If the crosscut pipe is located lower than the hot water outlet of the heat pump unit, raise the pipe near the unit and
install an automatic air venting valve.
Automatic air venting valve
Upward gradient 1/200
19 (3/4)
54 (2-3/16)
Air separator
Air venting valve installation example
Hot water outlet
(Bronze Rc3/4, female screw)
122 (4-13/16)
199 (7-7/8)
Front view
9 (3/8)
26 (1-1/16) 26 (1-1/16) 54 (2-3/16)
755 (29-3/4)
Side view
Automatic air venting valve
GB-16
Service panel
Automatic air
venting valve
Heat pump unit
Hot water outlet
Base
Crosscut pipe
[Unit: mm (in)]