14
Step 7 — Adjust Indoor-Fan Speed —
Adjust indoor-
fan speed to meet jobsite conditions.
For units with electric heat, required minimum L/s is 1062
(cfm is 2250) for 50TFQ008; 1203 (2550) for 50TFQ009; and
1416 (3000) for 50TFQ012 with the following exceptions:
Table 5 shows indoor-fan motor data. Tables 6 and 7 show
fan r/s and rpm at motor pulley settings for standard motors.
Refer to Tables 8-15 to determine fan speed settings. Fan motor
pulleys are factory set for speed shown in Tables 1A and 1B.
To change fan speeds:
1. Shut off unit power supply and tag disconnect.
2. Loosen belt by loosening fan motor mounting nuts. See
Fig. 24 and 25.
3. Loosen movable pulley flange setscrew (see Fig. 26).
4. Screw movable flange toward fixed flange to increase
speed or away from fixed flange to decrease speed. In-
creasing fan speed increases load on motor. Do not ex-
ceed maximum speed specified in Tables 1A and 1B.
5. Set movable flange at nearest keyway of pulley hub and
tighten setscrew. (See Tables 1A and 1B for speed change
for each full turn of pulley flange.)
To align fan and motor pulleys:
1. Loosen fan pulley setscrews.
2. Slide fan pulley along fan shaft.
3. Make angular alignment by loosening motor from
mounting plate.
To adjust belt tension:
1. Loosen fan motor mounting nuts.
2. Sizes 008 and 009 — Slide motor mounting plate away
from fan scroll for proper belt tension (16 mm [.6-in.] de-
flection with 4.5 kgf [8 to 10 lbs] of force) and tighten
mounting nuts (see Fig. 24).
Size 012 — Slide motor mounting plate downward to
tighten belt tension (16 mm [.6-in.] deflection with
4.5 kgf [8 to 10 lbs] of force) and tighten mounting nuts.
Secure motor mounting plate nuts. See Fig. 25.
3. Adjust bolt and nut on mounting plate to secure motor in
fixed position.
UNIT
50TFQ
UNIT
VOLTAGE
HEATER
kW
UNIT
CONFIGURA-
TION
REQUIRED
MINIMUM
L/s
Cfm
012
400
34.7
Horizontal
or Vertical
1510
3200
Fig. 23 — Durablade Economizer Barometric
Relief Damper Characteristics
Fig. 24 — Typical Belt-Drive Motor Mounting for
Size 008 and 009
Fig. 25 — Typical Belt-Drive Motor Mounting for
Size 012
MOTOR MOUNTING
PLATE NUTS
