User manual

Operating advanced function _43
ENGLISH
Backup Heater Variables for Space Heating
• The FSV #4021 should be set to “1(On)” to use 2-stage electric backup heater in hydro unit
as an additional heat source.
• To compensate the lowered heat pump heating performance under very cold weather
conditions, the FSV #4023 should be set to “1(On)”(Default).
 - The threshold temperature to use backup heater for cold weather compensation:
FSV #4024, Default “0˚C”, Range -15 ~ 35˚C
 - The backup heater operation is restricted to save energy in the threshold temperature
range.
• The FSV #4022 for backup heater priority should be set to “0(both)”(Default) or “1”(backup)
to use backup heater. If not(booster heater priority), the backup heater can be operated in
case of no booster heater demand.
•The threshold temperature for backup heater operation during defrost mode to prevent cold
draft because of chilled water can be controlled by adjusting FSV #4025. Under FSV #4025
of water outlet temperature, backup heater Will be turned on.
To use both heaters together at the same time, please check the capacity of the power
circuit breaker of your house before use.
External Backup Boiler for Space Heating (Field Option)
• The FSV #4031 should be set to “1(Yes)” to use a backup boiler as an additional heat
source. (default: “0 (No installation)”)
• Priority of backup boiler and heat pump is defined by FSV #4032 (default: “0(OFF)”)
• To compensate the lowered heat pump heating performance under very cold weather
conditions, the backup boiler operates instead of heat pump under the threshold
temperature (FSV #4033, Default “-15˚C”, Range -20 ~ 5˚C).