Mitsubishi Electric QAHV-N560YA-HPB, Service Handbook

Page: 43 / 176

[
II
Restrictions ]
- 36 -
HWE1517A GB
3. Water pipe hole size and location
4. Pipe gradient and air venting valve (Outlet hot water pipe)
5. Outlet check valve (When installing multiple units)
When connecting multiple units with pipes in parallel, install a check valve at the outlet pipe of each unit. If a check valve is
not installed, a circuit in which warm water flows back will be created in some units during the defrost cycle or abnormal stop,
and other units will come to an abnormal stop due to sudden change of the inlet water temperature.
19
755
26 54 54 26
9
206
274
297
85
90
85
122
199
Water inlet
(Bronze Rc3/4, female screw)
Service panel
Front view
Side view
Hot water outlet
(Bronze Rc3/4, female screw)
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
Automatic air venting valve
Air venting valve installation example
Air separator
Automatic air
venting valve
Hot water outlet
Crosscut pipe
Base
Heat pump unit
Upward gradient 1/200
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