SERVICING
42
S-207 MOTOR SHEAVE ADJUSTMENTS
Vl, Vm & 2vp Variable Pitch Key Type Motor
Sheaves
The driving and driven motor sheaves should be in alignment
with each other and the shafts parallel.
Vl & Vm Sheaves Adjustment
1. Loosen set screw “B” using a 5/32" Allen key.
2. Making half or full turns from closed position, adjust sheave
pitch diameter for desired speed. DO NOT OPEN MORE
THAN SIX FULL TURNS.
3. Tighten set screw “B” securely over flat.
4. Carefully put on belts and adjust belt tension. DO NOT
FORCE BELTS OVER GROOVES.
5. Ensure all keys are in place and the set screws tight before
starting drive. Recheck set screws and belt tension after
24 hours service.
NOTE:
Future adjustments should be made by loosening
the belt tension and increasing or decreasing the pitch
diameter of the sheave by half or full turns as required.
Readjust belt tension before starting drive.
C
B
VL & VM
NOTE:
Do not operate sheave with flange projecting
beyond the hub end.
S-300 TESTING PRIMARY LIMIT CONTROL
DCG units use a snap-disk type primary limit device. Some-
times referred to as "stat on a stick". The limit setting is fixed
and must not be readjusted in the field.
TESTING PRIMARY LIMIT CONTROL
Refer to the specification section to determine the proper limit
cutout temperature for the model being serviced.
In all instances the limit control is wired in series with the
ignition control.
If the temperature within the furnace should exceed this set-
ting, the control will open, de-energizing the ignition control
which in turn will open the electrical circuit to the gas valve.
The control will automatically reset when the temperature
within the combustion chamber is sufficiently lowered.
HIGH VOLTAGE!
Disconnect ALL power before servicing
or installing this unit. Multiple power
sources may be present. Failure to do so
may cause property damage, personal injury
or death.
1. Remove electrical power to unit. Some units may have
more than one source of power.
2. Remove the wires from the limit control terminals.
3. Using an ohmmeter, test for continuity across the two
terminals.
4. If limit test open allow unit to cool and retest.
5. If still open, replace the control.
Summary of Contents for DBG Series
Page 51: ...51 ACCESSORIES GAS ELECTRIC...
Page 52: ...ACCESSORIES 52 GAS ELECTRIC...
Page 53: ...53 ACCESSORIES...
Page 54: ...ACCESSORIES 54...
Page 95: ...95 DBC COMMERCIAL 15 25 Ton Packaged Air Conditioner Unit WIRING DIAGRAMS...
Page 100: ...100 DBG COMMERCIAL 15 25 Ton Packaged Gas Electric Unit WIRING DIAGRAMS...
