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9-6 Protection Operations In Heat Mode
1. Outdoor coil De-ice Protection
Protection
Condition A
RV1
(Condition B)
(RV3)
(RV4)
On
Any
De-icing
On
Off
On
Termination of
On
De-icing
Off
Notes:
1. Protection Mode is activated when any of the condition A or condition B is satisfied.
•
In De-icing mode, both systems (A & B) will always perform De-icing at the same time.
2. In the de-icing process:
(i)
The de-icing process can be triggered by any one of the OCT which is < -2
corresponding COMP, RV are both ON and de-icing timer counts to zero.
(ii)
The de-icing timer is stopped (the count is reserved) when both COM-A and COM-B
are OFF.
(iii)
The de-icing timer counts down when any of the compressor turn on.
(iv)
The de-icing timer is reset (to maximum count) when the condition "RV output of the
IDU are all Off or all OCT > -2
3. If the OF speed is marked as "Hi/Lo", its speed is governed by the outdoor air thermistor as
explained before.
INPUTS
RV2
CO1
CO2
OCT-A
(CO3)
(CO4)
(OCT-B)
Any
On
On
= -2
On
On
On
= -2
Off
On
Off
= -2
On
Off
On
= -2
On
On
On
> 12
Off
On
Off
> 12
On
Off
On
> 12
o
C" .
OUTPUTS
ORV-A
CO-A
OF-A
(ORV-B)
(CO-B)
(OF-B)
X
ON
X
X
ON
X
X
ON
X
X
ON
X
ON
ON
Hi / Lo
ON
ON
Hi / Lo
X
ON
Hi / Lo
27
SV-A1
SV-A2
SV-A3
(SV-B1)
(SV-B2)
(SV-B3)
ON
ON
X
ON
ON
X
ON
X
ON
X
ON
ON
ON
ON
X
ON
X
ON
X
ON
ON
o
C with the
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