Bard ECONOMIZERS WITH EXHAUST EIFM-5C - Manual (Page 8)

Manual 2100-447C
Page
8 of 13
10. Connect leads with fork terminal to corresponding
points on terminal strip. RE: C.Y.G. (See wiring
diagram.)
11. Wire nut leads with 5/8" stripped ends to Y1 and
Y2 leads from thermostat. See wiring diagram in
this manual.
NOTE: Wires referenced in note one on wiring
diagram are for special control application
only and are not normally used in conjunction
with other circuitry to open the damper
regardless of outside temperature and
humidity. Consult factory for details.
12. Close control panel cover.
13. Reinstall the blower access panel at top of unit and
secure with sheet metal screws.
14. Replace filter and screws in front condenser grille.
15. ECONOMIZER CHECK OUT
A. Remove mist eliminator (Figure 2). Locate the
minimum position potentiometer (See Figure 4).
B. Energize the evaporator blower by switching
thermostat to the manual fan position with
heat/ cool in the OFF position.
C. Cycle the minimum position potentiometer
(factory set for 0% fresh air) 0 to full open.
(See Figure 3.) Throughout checkout
procedure observe operation of damper to
insure there is free, unobstructed operation
through the entire angle of damper travel.
Then adjust the damper minimum open
position to meet local codes or application
requirements. See example below.
EXAMPLE:
1. Measure return air temperature (RAT)
(assume 75°F for example).
2. Measure outdoor air temperature (OAT)
(assume 60°F for example).
3. Calculate the mixed air temperature (MAT)
which will result from the desired
combination of OAT (10 percent) and RAT
(90 percent).
.1 OAT + .9 RAT = MAT
or substituting example values
.1 (60°F) + .9 (75°F) = 73.75°F
4. Adjust the minimum position potentiometer
knob until proper mixed air temperature as
calculated above is reached. Care should
be taken to insure thermometer is sensing
air that is well mixed.
5. Mark correct setting on dial of minimum
position potentiometer for future reference.
D. Adjust the enthalpy control to position A, B,
C and D to achieve the maximum combination
of temperature and humidity acceptable for the
installation as per Table 2 below. The
suggested setting is between A & B 70° DB
@ 55 percent RH. It is further recommended
to always set the control at C or above.)
(See Figure 4.)
E. Switch the thermostat fan control to automatic
and position the heat/cool switch to cool.
Adjust the thermostat temperature to engage
the first stage of cooling only (Y). This will
cause the dampers to modulate to achieve
mixed air temperature of 55° provided outside
air enthalpy is sufficiently low. If enthalpy is
too high for economizing, low enthalpy can be
simulated by temporarily removing and
jumping leads on terminal 2 and 3 of enthalpy
control together. This will also cause the
economizer damper to modulate away from
minimum position. (Be sure to properly
reconnect leads at end of checkout
procedure).
TABLE 2
ENTHALPY CONTROL SETTINGS
l a i D
g n i t t e S H R % 0 2 H R % 0 5 H R % 0 8
y p l a h t n E
l o r t n o C
g n i t t e S
A
F . g e d 0 8
) C . g e d 6 2 (
F . g e d 3 7
) C . g e d 3 2 (
F . g e d 6 6
) C . g e d 9 1 (
B
F . g e d 6 7
) C . g e d 4 2 (
F . g e d 0 7
) C . g e d 1 2 (
F . g e d 3 6
) C . g e d 7 1 (
C
F . g e d 4 7
) C . g e d 3 2 (
F . g e d 6 6
) C . g e d 9 1 (
F . g e d 9 5
) C . g e d 5 1 (
D
F . g e d 1 7
) C . g e d 1 2 (
F . g e d 3 6
) C . g e d 7 1 (
F . g e d 4 5
) C . g e d 2 1 (