Service manual

06/2010
6. Replace the gas solenoid 1073 per SM500-13.
7. Replace the modulating valve 1076 per SM500-14.
3.6 Green LED flashes, but no ignition (no igniter sparks, no gas
flow, no gas odor)
1. Check that the ignition wire 1412 is connected to the igniter and then check the wire for
continuity.
2. With gas OFF, check if the igniter is sparking to the burner (see figure -3). If not, find where the
igniter is sparking. The likely places would be from the bottom of the igniter to the burner bracket
and at the right side of the electrical drawer where the ignition wire can be forced against the
case. If the spark is at the electrical drawer side then re-route the ignition wire. If the spark is
going to the burner bracket, paint the burner bracket in that area with anti-rust paint, or else, cut
away the burner bracket so there is about 0.5 inch clearance with the igniter wire.
3. Check that the green (ground) wire on DSI cable 1333 is attached under the right-side screw at
the burner bracket (see figure -3).
4. Check the height of igniter electrode above the burner. This height should be 0.125 inch (see
figure -8).
5. Disconnect the ignition wire from the DSI spade connector in the electrical drawer (see figure -4).
During ignition a spark should be seen at the DSI spade connector. If there is none, replace the
DSI board 3158 per SM500-02. If there is a spark, replace the ignition wire 1412 and, find where
the spark is occurring along the ignition wire.
3.7 The unit ignites, but will not rise above minimum burn or
water at the faucet is cool
1. Check flow out of faucet by measuring the time it takes to fill a gallon container. Calculate
water flow in gallons per minute (GPM) by dividing the number one by the time in minutes it
takes to collect one gallon of water. Refer to figure -1 to be sure that you are in the normal
operating range.
2. If the last letter on your micro-controller EL 9049 is ‘D’ or later then the flow through the
RV500 can be read from the green LED as specified in section 4.3 ‘Reading flow using the
green LED’. If the flow at the faucet is more than 0.25 GPM greater than the flow through the
RV500, read about ‘Cold Water Bypass’.
3. Check the voltage to the modulating valve 1076 by placing multimeter probes in the 2-pin
connector (white and black wires) at the circuit board 1841-RV (see figure -4). If the voltage
is greater than 2.0 vdc, the modulating valve likely has been forced out of normal range and
needs to be returned.
4. While powered, tap on the gas pipe between the gas solenoid and the modulating valve. If
this does not free the valve, try using a magnet, starting at the brass fitting on the right side of
the coil lay the magnet on the pipe and move from right to left stopping at the wire coil and
pulling straight off, or try running AutoCal. (See SM 500-15). (Call for tech assistance 800-
934-9690).
5. Replace the modulating valve
6. If the voltage is less than 2.0 vdc: