Back-Up Operation Of Boiler; Supplementary Information - Mitsubishi Electric EHST20C-VM6HB Service Manual

SUPPLEMENTARY INFORMATION

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Refrigerant collecting (pumpdown) for split model systems only
Refer to "Refrigerant collection" in the outdoor unit installation manual or service manual.

Back-up operation of boiler

Heating operation is backed up by boiler.
For more details, refer to the installation manual of PAC-TH011HT-E.
<Installation & System set up>
1. Set Dip-SW 1-1 to ON "With boiler" and SW2-6 to ON "With Mixing tank".
2. Install the thermistors THWB1 (Flow temp.) and THWB2 (return temp.) *1 on the boiler circuit.
3. Connect the output wire (OUT10: Boiler operation) to the input (room thermostat input) on the boiler. *2
4. Install one of the following room temp. thermostats. *3
Wireless remote controller (option)
Room temp. thermostat (field supply)
Main controller (remote position)
*1 The boiler temp. thermistor is an optional part.
*2 OUT10 has no voltage across it.
*3 Boiler heating is controlled on/off by the room temp. thermostat.
<Remote controller settings>
1. Go to Service menu > Heat source setting and choose "Boiler" or "Auto". *4
2. Go to Service menu > Operation settings > Boiler settings to make detailed settings for "Auto" above .
*4 The "Auto" automatically switches heat sources between Heat pump (and Electric heater) and boiler.
OCH531
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