Reznor B5SM Option - Installation - Economizer - Manual (Page 4)

Heat Pump Ther mo stat – Sin gle "O/B" ter mi nal for
se lec tion of Re vers ing Valve Con trol.
(B4,B5)SM Series economizers are pre-wired to work in
conjunction with single stage Heat Pump thermostats that
utilize the "O" terminal to energize the reversing valve
when the thermostat "System Switch" is set in the "Cool"
mode. Refer to these installation instructions and wiring
diagrams for proper connection and operation of the
economizer. When the system switch is in the OFF, HEAT,
or EMERGENCY HEAT mode setting the economizer is
automatically locked out during heating operation. It holds
the outdoor fresh air damper at the minimum position
setting only when the air handler is operating. Refer to
Section VI – Minimum Damper Position for proper set
up and operation.
VI - SYS TEM CHECK AND START UP
PRO CE DURES
Min i mum Damper Po si tion Ad just ment.
Damper min i mum po si tion keeps the out door air damper
from clos ing com pletely dur ing sys tem op er a tion for
ven ti la tion of build ing con tam i nants and peo ple
oc cu pancy. Con sult your State or lo cal codes as required.
1. Disconnect main power to outdoor unit and air
handler.
2. Set thermostat "SYSTEM" switch to "OFF" position and
"FAN" switch to "AUTO".
3. Install jumper wire across air handler low voltage
terminal board "R" and "G" terminal.
4. Disconnect mixed air sensor from the W7212
terminals T and T1 and short terminals T and T1. See
Figure 5.
5. Ensure the factory installed jumper is in place across
terminals P and P1.
6. Calculate the appropriate mixed air temperature per
the following equation:
* (Return Air Temp. x % of Return Air) + (Outside Air
Temp. x % of Outside Air) = Mixed Air Temperature
Example:
Assume local code requires 10% outdoor air during
occupied conditions, (200 CFM of total unit CFM =
2,000) outdoor air is 60
o F, and return air is 75 o F.
Under these conditions, what is the mixed air
temperature?
(0.1 x 60 o F) + (0.9 x 75 o F) = 6.0 o F + 67.5 o F = 73.5 o F
7. Restore power to the outdoor section and air handler.
8. Carefully adjust the MIN POS potentiometer on the
W7212 control module with a small screwdriver until
the mixed air temperature reaches the calculated
value.
9. Once minimum position adjustments are completed,
turn off power to the outdoor unit and air handler.
Damper will move to fully close.
INSTALLATION
INSTRUCTION
INSTALLATION INSTRUCTIONS FOR
560199
ECONOMIZER USED WITH
(B4,B5)SM 090/120 SERIES AIR HANDLER
10. Remove jumper wire across "R" and "G" on the low
voltage terminal board and T and T1 on the W7212
control module.
11. Reconnect the mixed air sensor.
12. Restore power to outdoor unit and air handler.
VII - MAIN TE NANCE
1. Damper motor is prelubricated and does not require
further lubrication.
2. Make visual inspection of dampers and linkage
assemblies during routine maintenance.
3. Filters should be checked periodically and cleaned
when necessary.
4. The washable filters supplied with the economizer can
be cleaned with water and a mild detergent.
5. Take note of “Air Flow Direction” marking on filter
frame when reinstalling.
6. If filter must be replaced, filter of like kind and size must
be used. DO NOT replace permanent filters with
throwaway type filters.
4