cycle or passive defrost. For more information about the evaporator fan drip-time delay, see Figure
Evaporator fan time delay
The evaporator fan time delay holds the evaporator fan relays off or open after defrost termination,
drip-time delay, and compressor restart in cooling mode. During this time-based delay, 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 min to 15 min for the evaporator to freeze any remaining moisture, before the evaporator
fans turn on.
The following figure shows the controller relay states during defrost duration, drip time delay, and
evaporator fan delay. See Table 4 for a description of the callouts shown in the following figure.
Figure 5: Controller relay states
Table 4: Controller relay states callout table
Callout
Description
Compressor relay
Defrost relay
High speed fan relay
Relay off
Relay on
1
Defrost duration
2
Defrost termination
3
Drip time delay
4
Drip time ends
5
Evap fan delay cool down
6
Evap fan delay ends based on time
7
Normal cooling mode
MR5 Series Panel Mount Case Controller Technical Bulletin
14
Discontinued
