Manual 2100-484E
Page 10 of 22
DC FAN CONTROL
The primary reason the DC30002 or DC3003 controller
system would be used is for additionally controlling a
DC Fan ventilation system installed in the shelter in
addition to controlling either 2 or 3 HVAC units. The
DC Fan package and intake system is independent of the
HVAC systems, and is supplied by others.
A DC Fan pilot-duty control relay, Form C (SPDT) rated
at 1A is incorporated into both DC3002 and DC3003
alarm boards for this purpose. DC Fan package must
include the load control relay, or be otherwise field-
supplied.
The DC Fan control can be configured to be used as
follows:
1.For emergency ventilation only
2.For both free cooling and emergency ventilation
3.For free cooling only
The controller default setting is “Both”
When economizers are used in HVAC units 1 and 2 and
Free Cooling is selected, the economizer controls make
the decision when the DC Fan can be active as free
cooling or not. The logic is as follows:
1.As long as at least one of the HVAC economizers is
operating the DC Fan can operate
2.When outdoor conditions are not acceptable for free
cooling using the economizers or when indoor load
conditions as such that both economizers are forced
off, the DC Fan is turned off. This is monitored by
the Unit 1 and Unit 2 “Y” signals feeding from the
HVAC 1 and 2 units to the DC3002 or DC3003
internal alarm boards. If both Unit 1 and 2 Y signals
are present the DC Fan will not operate in Free
Cooling mode.
When economizers are not used, and Free Cooling with
the DC Fan is desired, and optional remote sensor Bard
Part Number 8612-023 must be used.:
1.Sensor is connected to main controller board OUT
terminals CU (copper wire) and AG (silver colored
wire). The sensor is polarity sensitive and will not
work correctly if connected in reverse.
2.The sensor must be located outside the shelter and
should be in a junction box for physical protection.
3.It should be on the north side of the shelter if
possible to keep from being influenced by the effects
of the sun.
4.In the Program menu under “dFon” there are 3
choices for the DC Fan decision for free cooling or
not: 50-55-60F. Factory default is 55F.
5.If set-point is 55F, the outdoor temperature must be
54F or colder for DC Fan to operate. Above 56F the
DC Fan would be inhibited for Free Cooling.
For Emergency Ventilation using the DC Fan package,
either “Emergency Ventilation Only” or “Both” must be
selected in the Program menu. This means that if the
shelter temperature rises to 1F above the High
Temperature #2 set-point, the DC Fan control relay will
be energized. The High Temperature #2 alarm relay also
is energized at the same time. Default setting for High
Temperature #2 is 90F.
NOTE: If economizers are installed, they can also be
used for emergency ventilation. See Emergency
Ventilation Sequence Using Economizers on page 16.
DC FAN PURGE OPTION
The DC Fan can also be used for intermittent purge cycle
if desired for purpose of controlling out-gassing from
storage batteries or for any other reasons.
DC Fan purge duration is defined in minutes:
1.Shown as “Purg” in Programming Menu
2. Choices are No, 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10-minutes
3. Default is set to No
DC Fan purge interval is defined in hours:
1.Shown as “Pint” in Programming Menu
2. Choices are 1, 2, 3, 4, 5, 6, 7, 8 up to 24-hours
3.Default is 1-hour
4.The “Pint” display is suppressed if Purg is set to No
NOTE: The purge interval starts at the end of the
selected purge duration.
CONTROLLER WIRING
The DC3002 can be used for controlling two (2) air
conditioners with or without economizers. The DC3003
can be used for controlling three (3) air conditioners
with or without economizers. Units with economizers
will connect differently than units without economizers;
therefore, it is important to use the correct connection
diagram. See Table 1 for correct connection diagrams.
noitcennoC margaiD rellortnoC ledoM fo.oN CAVH
dellatsnIrezimonocE
CAVH 1# CAVH 2# CAVH 3#
1erugiF 2003CD2seYseY---
2erugiF 2003CD2
oNoN---
3erugiF 3003CD3ro2seYseYseY
4erugiF 3003CD3ro2seYseYoN
5erugiF 3003CD3ro2oNoNoN
TABLE 1