13
Figure 7: ASD overriding load demand to maintain compressor relay off
Evaporator fan drip-time delay
The evaporator fan drip-time delay holds the compressor relay, defrost relay, and the evaporator relay off (contacts
open) after the defrost duration terminates. This user-defined drip-time delay means that the evaporator coil can
shed additional water and reduces the moisture that blows into the refrigerated space when the evaporator fans
start. Select from 0 minutes to 10 minutes for the evaporator fan drip-time delay. The evaporator fan drip-time delay
is unavailable for off-cycle (passive) defrost. For more information about the evaporator fan drip-time delay, see
Figure 8.
Evaporator fan time delay
The evaporator fan time delay holds the evaporator fan relays off (contacts open) after the defrost termination, drip-
time delay, and compressor restart in cooling mode. This time-based delay means that the evaporator coil cools
down and freezes any moisture before the evaporator fan or fans start. This delay reduces the water and warm air
that blows into the refrigerated space. Select a time delay from 0 minutes to 15 minutes for the evaporator to freeze
any remaining moisture, before the evaporator fans turn on.
Table 6: ASD overriding load demand callout table
Item Description
Relay off
Relay on
Normal on/off refrigeration cycle based on load demand
ASD overrides load demand
When ASD elapses,
the existing demand
closes the relay (on)
ASD starts
when the relay
opens (off)
Load demand
Compressor
relay
ASD
ASD
ASD
Compressor
relay cycling on
load demand
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