A.O. Smith BT-100-LP, Instruction Manual

Page: 34 / 47

34
Never use this water heater unless it is completely
filled with water. To prevent damage to the tank,
the tank must
be filled with water. Water must flow
from the hot water faucet before turning “ON” gas
to the water heater.
Read this manual first. Then before checking the
water heater make sure the gas supply has been
turned “OFF”, and never turn the gas “ON” before
the tank is completely full of water.
Never use this water heater unless it is completely
filled with water. To prevent damage to the tank,
the tank must be filled with water. Water must flow
from the hot water faucet before turning “ON” gas
to the water heater.
Leakage from other appliances, water lines, or
ground seepage should also be checked.
REMOVING AND REPLACING THE GAS CON-
TROL VALVE/THERMOSTAT
IMPORTANT: This water heater has a resettable
thermal switch installed. Do not attempt to disable
or modify this feature in any way. Use only factory
authorized replacement parts. IMPORTANT: This
gas control valve/thermostat is shipped from
the factory as a natural gas unit. However,
it may be converted to use LP gas. Before
installing this gas control valve/ thermostat,
make sure that it is configured for the type of
gas that you are using.
REMOVING THE GAS CONTROL VALVE/THERMOSTAT:
1. Turn the gas control/temperature knob to the
OFF position. See
Figure 22
(page 24) .
2. Turn off the gas at the manual shut-off valve on
the gas supply pipe.
3. Drain the water heater. Follow the instructions in
Draining and Flushing
(page 32) .
4. Disconnect the igniter wire from the igniter lead
wire. Use needle nose pliers to disconnect
the red (+) and white (-) thermopile wires.
Disconnect the pilot tube (7/16” wrench) and
manifold tube (3/4” wrench) at the gas control
valve/thermostat. See
Gas Control Valve
Removal
(page 34) .
IGNITER
WIRE
RED WIRE
(LEFT SIDE)
PILOT
TUBE
MANIFOLD TUBE
IGNITER
BUTTON
IGNITER
LEAD
WIRE
WHITE
WIRE
(RIGHT
SIDE)
GAS CONTROL/
TEMPERATURE KNOB
VAC
FIGURE 27. GAS CONTROL VALVE REMOVAL
5. Referring to
Figure 28
(page 34), disconnect the ground
joint union in the gas piping.
6. Disconnect the remaining pipe from the gas control valve/
thermostat.
FIGURE 28. PIPING CONFIGURATION
7. To remove the gas control valve/thermostat, thread a 4”
section of gas pipe into the gas inlet and use it to turn the
gas control valve/thermostat (counterclockwise.) Do not
use a pipe wrench or equivalent to grip body. Damage may
result, causing leaks. Do not insert any sharp objects into
the inlet or outlet connections. Damage to the gas control
valve/thermostat may result.