Annual Maintenance - Mitsubishi Electric ecodan EHPX-Serie Installationshandbuch

7
Service and Maintenance
No. Fault symptom
27 The hydrobox that The hydrobox is designed to run in an operation
mode with a higher priority (i.e. DHW mode in this
was running in the
case) at power recovery.
heating mode before
power failure is
running in the DHW
mode after power
recovery.
28 Cooling mode is NOT Dip SW2-4 is OFF.
available.
29 The cooling system . When the water in the circulation circuit is un-
duly hot, Cooling mode starts with a delay for
does not cool down to
the protection of the outdoor unit.
the set temperature.
2. When the outdoor temperature is lower than
the preset temperature below which the
freeze stat. function is activated, Cooling
mode does not start running.
30 The electric heaters The setting time period of Heat-pump-only opera-
tion is short.
are activated shortly
after DHW or LP
mode starts running
after Cooling mode.
3 During DHW or LP If the preset temperature below which the freeze
stat. function is activated is low, error L6 is more
mode following the
likely to occur interruption operation before the
cooling mode, error
freeze stat. function is activated.
L6 (circulation water
freeze protection)
occurs and operation
stops frequently.

Annual Maintenance

It is essential that the hydrobox is serviced at least once a year by a qualified individual any spare parts required MUST be purchased from Mitsubishi Electric (safety matter).
NEVER bypass safety devices or operate the unit without them being fully operational.
<Draining the hydrobox>
WARNING: DRAINED WATER MAY BE VERY HOT
. Before attempting to drain the hydrobox islolate from the electrical supply to prevent booster heater burning out.
2. Isolate hydrobox from primary water circuit and drain water from hydrobox. Use a suitable heat resistant hose to assist in these operations.
3. Drain any remaining water from booster heater using fitted drain cock and hose to safely drain the unit.
4. After the hydrobox is drained, water remains in the following component parts. Drain water completely by checking the inside of the parts.
• Strainer (Remove the strainer cover.)
• Pressure relief valve (Operate the valve.)
<Annual maintenance points>
Use the Annual Maintenance Log Book as a guide to carrying out the necessary checks on the hydrobox and outdoor unit.
Possible cause
• Normal operation.
• After the DHW max. operation time has elapsed or the DHW max. temperature has
Turn Dip SW2-4 to ON. (Refer to "5.1 Dip Switch Functions" in this manual.)
.
2.
Adjust the setting time period of Heat-pump only operation. (Refer to "<Electric heater
(DHW)> on Page 47.
Adjust the preset temperature below which the freeze stat. function is activated. (Refer
to "<Freeze stat function>" on Page 49.
Explanation - Solution
been reached, the DHW mode switches to the other mode (ex. Heating mode).
Normal operation.
To run Cooling mode overriding the freeze stat. function, adjust the preset tem-
perature below which the freeze stat. function is activated. (Refer to "<Freeze stat
function>" on Page 49.
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