Service manual
06/2010
6. Examine the micro-controller EL 9049 (see figure -4). Be sure that all pins are in the socket
and none appear bent (use thumb to gently press on the chip).
7. If the problem persists then change board 1841-RV. Refer to SM500-01 for the change
procedure.
3.4 Green LED flashes, but no ignition attempt (no igniter, no
gas)
1. Is the water ON and is the flow out of the faucet at least 0.5 gallons per minute (2.5 minutes
to fill 1 gallon)? Flow must be greater than 0.5 GPM for the unit to turn on.
2. Check the T-in, T-mid, and T-out thermisters (see section 4.3 ‘T-in, T-mid, T-out Thermister
and T-set readout’).
3. Find the RV500 flowmeter (see figure -3) and verify that the black rotor, visible through the
transparent cover, is rotating which indicates that there is flow going through the unit. If the
flowmeter is not turning or turning slowly so that the rotor spokes are clearly visible there
may be cold water leaking into the hot water lines somewhere in the coach. See the
description under the problem Section 4.1 ‘Cold Water Bypass’ to learn more about this
condition. If the last letter on your micro-controller 9049 is ‘D’ or later, the flow through the
RV500 can be read from the green LED as specified in section 4.3 ‘ Reading flow using the
green LED’.
4. Place a finger on the ignition relay on the circuit board (see figure -4) and turn on water. Do
you feel or hear a click of the relay actuating?
5. If NO, inspect the micro-controller EL 9049 to confirm that it is pushed in fully and that no
pins appear bent or out of the socket If the micro-controller is okay then replace the circuit
board 1841-RV per SM500-01.
6. If YES, check that 12 vdc goes to the DSI board 3158 (see figure -4) at the left white wire.
If YES, check that the green (ground) wire on DSI cable 1829 is attached under the right-
side screw at the burner bracket (see figure -3). If green ground wire is attached then
replace the DSI 3158 per SM500-02. If NO, replace the DSI cable 1829.
3.5 Green LED flashes, but no ignition (igniter sparks, no gas)
1. Check the ECO for an open circuit by checking continuity on each connector. On older models
check the pop-out button on the ECO 1293 and push in; newer models have auto reset (no
button). The ECO is a bi-metal switch that opens when temperature goes above 165F.
2. (see figure -3)
3. Check that the propane tank is ON and there is gas in the tank. Gas pressure to the RV500
while running should be 11.0–14.0 wci. Gas pressure may be too low due to improper gas line
diameter (under ¼” diameter) or the gas line being too long (over 25 feet) or ON/OFF solenoid at
tank, if you have a solenoid, may have an orifice that is too small (under 3/16” diameter).
4. Check that all four spade connectors are secure to the gas solenoid 1073 (see figure -3). Check
that 12 vdc is getting to the gas solenoid 1073 (see figure -3). Removing the top and/or bottom
spade connections at the gas solenoid and measuring voltage between the blue and white leads.
If there is no voltage or the voltage is less than 10.0 vdc, replace the DSI cable 1829.
5. Use a wrench or similar tool to tap on the gas supply pipe to the right of the coil on the
modulating valve 1076 (see figure -3). It is possible that the piston in the modulating valve has
been forced out of its normal range and may stick. The tapping helps to free the valve