Service manual

150158 Rev. 2 August - 2010
12
DAMPER OPERATION SEQUENCE
OTHER THAN THE ONE LISTED ON THE RATING
PLATE
(Figure 5). Failure to use the correct gas can cause
problems which result in
DEATH, SERIOUS BODILY
INJURY, OR PROPERTY DAMAGE.
If you have any
questions or doubts consult your gas supplier or gas company.
NATURAL GAS MODELS
IF YOU SMELL GAS:
1. Open windows.
2. Get all people out of the building.
3. DO NOT light matches.
4. DO NOT touch electrical switches (on or off).
5. Extinguish any open flames.
6. Use an outside phone and immediately call the gas
company and the fire department. Ask for instructions.
Before hanging up, give your name and address.
7. DO NOT go back into the building. If help is coming, wait
for it outside of the building.
L.P. (PROPANE, BOTTLED)
GAS MODELS
L.P. GAS IS HEAVIER THAN AIR
Should there be a leak in the system, the gas will settle at
FLOOR LEVEL. Basements, crawl spaces, skirted areas under
mobile homes (even when ventilated), closets and areas below
ground level will serve as pockets for the accumulation of gas.
BEFORE LIGHTING, sniff at FLOOR LEVEL
IF YOU SMELL GAS, FOLLOW THESE RULES:
1. Open windows.
2. Get all people out of the building.
3. DO NOT light matches. Extinguish any open flame.
4. DO NOT touch electrical switches (on or off).
5. SHUT OFF GAS at L.P. tank outside of the building.
6. Use an outside phone and immediately call the gas
company and the fire department. Ask for instructions.
Before hanging up, give your name and address.
7. DO NOT go back into the building. If help is coming, wait
for it outside of the building.
OUT OF FUEL
When your L.P. tank runs out of fuel, turn off gas at all gas
appliances including gas to pilots. After L.P. tank is refilled,
all appliances must be re-lit according to the manufacturer’s
instructions, Page 13
.
EXPOSURE TO WATER
Do not use this appliance if any part has been under water.
Immediately call a qualified service technician to inspect the
appliance and to replace any part of the control system and
any gas control which has been under water.
FIGURE 11
OPERATION
In the standby condition (thermostat satisfied) relay contacts
R1 are closed and the motor (DM) is energized, which drives
the damper vane closed. This opens the endswitch (ES) via a
cam on the drive rod. When the damper is fully closed, the
safety switch (N/C) contacts (SS1) are closed by the other
drive rod cover. The torsion spring is wound up. Closure of the
thermostat (TH) energizes the relay coil (R) which opens the
R1 contacts. The motor is de-energized and the spring drives
the damper vane to the open position, the cam opens the safety
switch contacts (SS2) and closes (SS1), and the endswitch
contacts (ES). Closing of the endswitch energizes the control
module. When the thermostat is satisfied, it de-energizes the
control module and the relay coil (R). De-energizing the relay
closes the R1 contacts which energizes the motor, driving the
damper vane to the closed position.
I n the event of an endswitch malfunction, where the contacts
remain closed, the safety circuit detects this condition and
disables the damper in the open position. This is accomplished
when the thermostat closes on the next call for heat, by a
direct short through contacts, (SS2), (ES), the fuse, and the
thermostat. The short causes the fuse to blow, opening the
motor circuit, which causes the damper to spring open and
remain open. This will disable the damper in the open position
and allow the appliance to remain operational.
WARNING
TO AVOID POSSIBLE INJURY, FIRE AND EXPLOSION,
READ THESE PRECAUTIONS BEFORE ATTEMPTING
TO LIGHT OR RELIGHT THE PILOT.
Check the rating
plate near the gas control valve thermostat for correct gas.
DO
NOT USE THIS WATER HEATER WITH ANY GAS
LEGEND
DM Damper Motor
F Fuse
TH Thermostat
ES Endswitch
CM Control Module
R Relay Coil
R1 N/C Relay Contact
R2 N/O Relay Contact
SS1 N/C Safety Switch Contact
SS2 N/O Safety Switch Contact