Dettson Lowboy 154 Series, Installation Instructions And Homeowner'S Manual

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2.10 SUPPLY AIR ADJUSTMENTS
(4 SPEED MOTORS)
On units equipped with 4-speed blower motors, the sup-
ply air must be adjusted based on heating/air condition-
ing output and the static pressure of the duct system. For
the desired air flow refer to Table 1 as well as the table 9
based on static pressure in the Technical Specifications
section of this manual.
Figure 5 – Blower “OFF” delay - Board #ST9103A
To effect the adjustment, the RED (for heating) and BLUE
(for cooling and heat pump) wires can be changed on the
motor.
Also, refer to the position of the wires on the
electronic board of the unit and consult the wiring dia-
grams. If the heating and air conditioning speeds are
the same, the RED wire must be moved to “UNUSED
LEADS” on the electronic board and the jumper provided
with the BLUE wire must be used between the “HEAT”
and “COOL” terminals.
The blower start/stop delays can be adjusted by position-
ing the DIP switches on the electronic board as shown in
the following figures. For upflow installation, the recom-
mended blower ON delay is 60 seconds and blower OFF
delay 2 minutes.
Figure 6 – Blower Start/Stop Delays - Board#1158
Carte#1158 Board
Table 1 – Blower speed adjustments, heating mode, 4-speed motor
HEATING
CAPACITY
(USGPH)
STATIC
PRESSURE
(w.c.)
RECOMMENDED
BLOWER SPEED
0.90 0.25” MED-LOW
0.90 0.50” MED-LOW
1.10 0.25” MED-HIGH
1.10 0.50” MED-HIGH
10