S-304 Testing Gas Valve - Amana PHB**C Service Instructions Manual

SERVICING
If the rollout control has opened, the circuit between the igni-
tion control and gas valve will be interrupted and the ignition
control module will go into lockout. The servicer should reset
the ignition control by opening and closing the thermostat
circuit. The servicer should look for the ignitor glowing which
indicates there is power to the ignition control. The servicer
should measure the voltage between each side of the rollout
control and ground while the ignition control is trying to power
the gas valve.
Limit Switch Operation (Applies to Primary, Auxiliary, and
Roll Out Limits) DSI systems
If a limit switch opens, the indoor blower is energized on heat
speed and the induced draft blower is energized. The LED
on the control flashes "4" to indicate an open limit switch.
The blower and inducer remain on while the limit switch is
open. The gas valve is de-energized. Power to the thermo-
stat "R" is removed while the limit switch is open.
When the limit switch re-closes, the induced draft motor runs
through its post purge and the indoor blower goes through
the heat off delay.
If a call for heat exists when the limit switch re-closes, the
control goes through a pre-purge period and then makes an
ignition attempt. The indoor blower remains on (for the delay
off time) during the re-ignition attempt.
a. If no voltage is measured on either side of control it
indicates ignition control or wiring to control problem.
b. If voltage is measured on one side of the control and
not the other, it indicates the control is open.
c. If voltage is measured on both sides of the control the
wiring to gas valve or valve is at fault.
Servicing procedure with furnace not firing.
1. Confirm that the outer door was in place and all screws
tightened. (No leaks under the door.)
2. Check to see if any damage was done to the furnace
especially the wiring.
3. Confirm that heat exchanger is not obstructed by feeling
for discharge air from the flue hood when the combustion
blower is running but the unit is not firing.
If the above steps do not suggest the reason the control has
tripped the furnace should be fired.
1. Remove the heating compartment door.
2. Turn off the power or open the thermostat circuit.
3. Reset the roll-out control.
4. Turn power on and put the unit into a call for heating.
A
SSUME FLAME ROLL-OUT COULD OCCUR.
DISTANCE FROM BURNER AREA.
58
CAUTION
K
EEP FACE AND HANDS A SAFE
5. Look under the heat shield as the unit is running. Flames
should be drawn into firing tubes.
A. If only one burner flame is not drawn into the tube,
that tube is restricted.
B. If with out the air circulation blower running, all
flames are not drawn into the tubes either the col-
lector box, combustion blower, or flue outlet is ob-
structed. If the combustion blower or flue outlet is
obstructed, the pressure switch should have opened
preventing the unit from firing, also inspect the unit
pressure switch and wiring.
C. If the burner flame is not drawn into the tube only
when the air circulation blower is running, then a
cracked heat exchanger tube is present.

S-304 TESTING GAS VALVE

Smart Valve Systems
Amana ® brand package units utilize Honeywell "Smart Valve"
gas valves which provides all manual and automatic control
functions required for gas fired heating equipment.
UNUSED
3
MOTOR
S LEADS
1
2
S S
HEAT FAN
120
DELAY
C
OFF
60
SMART VALVE FAN TIMER BOARD
NORMAL SEQUENCE OF OPERATION
1. Thermostat calls for heat. The combustion blower is im-
mediately energized.
2. The pressure switch contacts transfer.
3. The ignitor is energized and pilot gas begins to flow.
4. After pilot flame is proven, the main valve is energized
and the pilot will light the main burners.
5. The control checks the signal from the flame sensor. Gas
flow will continue only if a proper signal is present. As
soon as pilot flame is proven, the ignitor is de-energized.
6. The unit will continue to fire for 30 seconds. The fan con-
trol will then start the main circulating air blower.
2 C X
1 3 4
NEUTRAL
XFMR SEC
C H
O E
O A
L T
C G Y W R
Y