9
240011511 REV. C [05/31/2017]
Belt Drive Blower Systems
WARNING
Improper installation could result in death or serious
injury. Belt drive components operate at high speeds
and may snag loose clothing resulting in injury or
death. Have a trained service professional preform
the following instructions. Failure to follow these
instructions could result in death or serious injury.
!
Belt drive blower systems can be modified for speed and air deliv
-
ery by adjusting variable speed motor pulley and changing blower
pulley.
• Adjust variable speed motor pulley by loosening 5/32 Allen
set screw in outer sheave. Turn outer sheave clockwise to
increase blower speed, counter clockwise to reduce speed.
•
Verify setscrew is tightened at one of the flat spots, failure
to do so will convert the variable speed pulley to a fixed
speed pulley by ruining the threads.
• Modify blower speed by changing the blower pulley. Smaller
blower pulley will cause the blower to turn faster. Large
pulley reduces blower speed.
• Large increases in the blower speed may increase power
requirements.
• Check amperage draw of the blower motor after making
changes. If amperage draw is greater than the value listed
on the motor rating plate, replace with motor of higher
horsepower.
•
Deflection of 3/4 of an inch to 1 inch fan belt tension is
necessary. Less deflection places a strain on the blower
bearings and increases start up amperage draw.
•
More deflection allows excess slippage and causes
premature motor pulley wear.
• Automotive belt dressings are not recommended.
• Bar soap will work as belt dressing to reduce belt squeaks,
etc. If using soap apply to the sides of belt only.
If operating belt drive blower at speeds above 1100 RPM, replace
sintered bronze blower bearings with roller bearings.
WARNING
Electrical shock hazard. Turn OFF electrical power
supply at service panel before opening blower access
door. Failure to do so could result in death or serious
injury.
!
22b. Circulating Air Blower (LRFV)
LRFV furnace models are equipped with electronically commutated
motors (ECM).
Setting Blower Speed and “ON” and “OFF” Timings
Blower speed and on/off time delays are handled by ECM motor
programming and are set via dipswitches per Table A-10.
Heating airflow rate is SW1 and on/off delay is SW4, both are set
according to firing rate. Cooling airflow rate is SW2 and if used
is set according to installed cooling capacity. SW3 can be used
to adjust airflow rate by (+) or (-) 15%. Features of this ECM
variable speed motor are that it will deliver a constant airflow
within a wide range of external static pressures, and also includes:
• Soft Start:
ECM will slowly ramp up to required operating
speed. In heating cycle allows heat exchanger to reach
operating temperature before set heat speed, minimizes
noise and increases comfort.
• Soft Stop:
At end of heating cycle, ECM will slowly ramp
down. Allows increased energy efficiency and reduced noise
levels.
• Dehumidification:
Feature is programmed into the variable
speed motor. At start of each cooling cycle, variable speed
motor will run at 82% of rated airflow for 7.5 minutes. After
7.5 minutes has elapsed, motor will increase to 100% of
rated airflow. Used to provide dehumidification and improve
system efficiency.
• Continuous Fan Operation:
When thermostat continuous
fan (G) switch is on without call for heating or cooling,
indoor fan is immediately energized at 50% of cooling speed.
Allows continuous circulation of air between calls for heating
or cooling. If call for heat (W) or cool (Y) occurs during
continuous fan, blower remains energized.
23. Maintenance And Service
Routine Maintenance By Home Owner
• Arrange for professional servicing of furnace by the service
or installation contractor annually.
•
Homeowner is to maintain air filter or filters. A dirty filter
can cause furnace to over-heat, fail to maintain indoor
temperature during cold weather, increase fuel consumption
and cause component failure.
•
Inspect, clean or replace filter monthly.
•
Furnace is supplied with semi-permanent type filter. If filter
is damaged, replace with filters of same size and type.
•
During monthly filter inspection, inspect general condition of
furnace. Watch for signs of oil leaks in vicinity of oil burner,
soot forming on any external part of furnace, soot forming
around joints in vent pipe, etc. If any of these conditions are
present, please advise your service or installation contractor.
