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TABLE 5 – CONDENSER FAN CONTROL
(EPROM VERSIONS C.A32.09.02 (0483),
C.ACS.09.02 (D87E), AND C.A06.09.03
(EIOC)
Turn on a Fan Stage
Every 5 sec
285 PSIG
Turn on a Fan Stage
every 15 min
250 PSIG
Discharge Pressure 150 – 250 PSIG
150 PSIG
Turn off Fan Stage
every 15 min.
120 PSIG
Turn off a Fan Stage
every 5 sec.
0 PSIG
Note: A low Oil - Suction differential Pressure less than 75 PSID
will cause the micro to turn a fan stage Off every 5 sec. This
will override pressure control of the fans.
TABLE 6 – CONDENSER FAN CONTROL AND FAN CONTACTOR DATA FOR DXST UNITS
WITH 3 FANS/SYSTEM (EPROM VERSIONS C.A14.09.03 (A85F), OTHER .03 VERSIONS, AND
HIGHER
Fan
Stage
Fans
1
1
SYS1
2
3
3
5
4
1, 5
SYS2
5
3, 5
6
1, 3, 5
* Sys 1 Outputs are on Relay Board #1
Sys 2 Outputs are on Relay Output Board #2
170
ON *
OFF *
Conditions
Conditions
DP
DP & OAT
>205 PSIG
<135 PSIG & <60°F
>265 PSIG
<160 PSIG & <65°F
>285 PSIG
<180 PSIG & <70°F
>205 PSIG
<135 PSIG & <75°F
>265 PSIG
<160 PSIG & <80°F
>285 PSIG
<180 PSIG & <85°F
EPROM Version C.A14.09.03 (A85F),
other .03 versions and higher
Fan operation is outlined in Table 6. Condenser fan ON
conditions are governed solely by the Discharge Pressure
(DP). When the DP rises above 205 PSIG, fan stage 1 is
activated. From there, subsequent fan stages are activated
as the discharge pressure rises. The system will remain at
the highest fan stage reached unless the OFF conditions
outlined in the next paragraph are satisfied.
Condenser fan OFF conditions are governed by both the DP
and OAT. Fan staging will be decreased from the highest
fan stage reached if both the DP and OAT requirements
are met. For example, if a system is at fan stage 3, and the
DP falls below 195 PSIG and the OAT drops below 75°
F, the fan stage will be reduced to stage 3.
Fan
Contactor
9M
10M
11M
9M, 11M
10M, 11M
9M, 10M, 11M
Wire
Relay
Number
Board
Output*
130
15
131
14
132
10
130, 132
10,15
131, 132
10, 14
130, 131, 132
10, 14, 15
JOHNSON CONTROLS
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