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12. The following symptoms do not indicate malfunctions.
Situation
The heater is not energized at TH7 ≤ 4°C.
The panel heater is cold even though the heater ON
conditions are met.
The heater does not turn off when TH7 ≥ 4°C.
The drain water is drained from the top of the outer panel of
the outdoor unit.
Ice between the outer panel and the inner panel does not melt.
Ice is formed at both edges of the heater.
Water freezes between units that are densely installed.
Explanation
• Panel heater ON conditions are not met.
- Panel heater ON conditions: Outdoor temperature is 4°C or
below (TH7 ≤ 4°C), and heating operation (including defrost
operation) is being performed.
To prevent burn injury, temperature of each surface is
individually controlled so that the energization is stopped for
areas where the heater sheet metal temperature becomes too
high. Therefore not all heaters may be energized.
* Note: Resistance at the terminal that stops the panel heater is
1440 Ω ± 7% when the unit is turned off and the panel heater
surface temperature is 40°C or below. (If the resistance is
2880 Ω ± 7%, either of the cables may be broken.)
The outdoor unit performs operation by sucking in outside air.
Therefore the panel heater tends to be cold while the outdoor
unit is in operation. Check the panel heater during defrost.
* Note: The panel heater temperature during the defrost
operation ≈ outdoor temperature + 15 deg
• Panel heater OFF conditions are not met.
- Panel heater OFF conditions: The outdoor unit is in cooling
mode or stop mode, or the compressor is stopped, or
[outdoor temperature is above 7°C (TH7 > 7°C) and three
minutes have passed since the defrost operation is
completed].
Even when the panel heater is turned on, it is normal that
water is drained from the outer panel of the outdoor unit.
Water is drained from the outer panel of outdoor unit because
the panel heater is used for maintaining water drainage from
the outdoor unit panel.
The center part of the heater is heated to collect and drain
water. Therefore ice may be formed at both edges.
If units are installed too close to each other, drain water from
the heater may freeze and accumulate between units. There
will not be a problem unless the top panel of the heater is
covered with ice.
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