SERVICING
55
M
a
no
m
e
t
er
M
a
n
o
m
e
t
e
r
H
o
s
e
Common
Terminal(C)
High Fire Coil
Terminal (HI)
Low Fire Coil
Terminal (LO)
Inlet Pressure Tap
1/8 NPT
O
p
e
n
t
o
A
t
m
o
s
p
h
e
r
e
Outlet Pressure Tap
1/8 NPT
Honeywell Model VR9205 Connected to Manometer
1. Remove regulator cover screw from the low (LO) outlet
pressure regulator adjust tower and turn screw clockwise
to increase pressure or counterclockwise to decrease
pressure. Replace regulator cover screw.
a. Close thermostat “R” and “W” contacts to provide a call
for heat.
b. Remove regulator cover screw from the high (HI)
outlet pressure regulator adjust tower and turn screw
clockwise to increase pressure or counterclockwise to
decrease pressure. Replace regulator cover screw.
system.
d. Remove the manometer hose from the outlet pressure
boss.
pressure tap. Replace the outlet pressure boss plug
and seal with a high quality thread sealer.
G
TG
T
TR R T G
BR RG R TG
2. Turn on gas to furnace and check for leaks. If leaks are
found, repair and then reinstall burner compartment door.
3. Turn on electrical power and verify proper unit operation.
Make sure furnace operates at the proper manifold
pressure at both high and low stage outputs.
High Stage
3.2 to 3.8" w.c.
3.5" w.c.
Low Stage
1.6 to 2.2" w.c.
1.9" w.c.
G
TG
T
TR
R
T
G
BR RG R TG T T
T R R B RT
R T
RRT G R JR R T
G TG
T TR R T G
BR RG R TG
High Stage
9.7 to 10.3" w.c.
10.0" w.c.
Low Stage
5.7 to 6.3" w.c.
6.0" w.c.
use a 120V silicon
nitride igniter for ignition. The normal operating temperature
is approximately 2156°F - 2678°F. At room temperature the
ignitor ohm reading should be from 37-68 ohms.
7. Place unit in heating cycle, measure current draw of ignitor
during preheat cycle.
The steady state current at 120V is 0.37 to 0.68 amps.
8. After checking and/or replacing of hot surface ignitor,
reinstall burner compartment door and verify proper unit
operation.
Flashback will also cause burning in the burner venturi, but is
caused by the burning speed being greater than the gas-air
Flashback may occur at the moment of ignition, after a burner
extinction pop.
should be made to determine which has occurred.
1. Improper gas pressure - adjust to proper pressure (See
S-307 CHECKING GAS PRESSURE)..
2. Check burner for proper alignment and/or replace burner.
The pressure control is a safety device to prevent the
combustion cycle from occurring with inadequate venting
caused by a restricted or blocked vent pipe. In addition to
the inducer pressure switch, this furnace has a “front cover
pressure switch” wired in series with the gas valve. This
To Next Page
Loading...
