Rinnai REU-2018W Service Manual page 41

17) Is the modulating valve operating normal?
18) Is the water flow servo normal? (2008/2408)
Infinity REU-2425W
ad. # Disconnect the modulating valve
festoon terminals and measure the
resistance at the terminals.
Normal: 60 ~ 100
If normal, go to (ae).
Faulty: Replace the modulating valve.
ae. Re-connect terminal and measure
the pink ~ pink voltage at the
modulating valve festoon terminal.
Normal: DC 0.5 ~ 25 V
If normal, go to (af) below.
Faulty: Replace PCB unit.
af. Investigate the change in gas
secondary pressure when the
remote control preset temperature is
altered from 37 to 75 C.
Normal: If the secondary pressure
changes, proceed to check item 4)
below.
Faulty: Replace the modulating valve.
ag. # Disconnect connector and
measure the red ~ blue resistance on
the water flow servo side.
Normal: 10 ~ 30
If normal, go to (ah).
Faulty: Replace the water flow servo
with water flow sensor.
ah. Disconnect connector, and measure
the voltage between orange (+) and
grey(-) on the water flow control side.
Normal: DC 11 ~ 13 V
If normal, go to (ai).
Faulty: Replace the PCB unit.
ai. With connector (E
not turn water ON... wait for the water
flow servo to return to fully open),
measure the voltage between brown
and grey.
Normal: DC 4 ~ 6V
Faulty: Change water flow servo with
sensor.
aj. Leaving the relay connector (E
connected (do not turn water ON...
wait for the water flow servo to return
to fully open), measure the voltage
between yellow and grey.
Normal: Less than DC 0.5 V
Faulty: Change water flow servo with
sensor.
- 38 -
Ω
°
Ω
) connected (do
1
)
1
Issue 2 - 5/07/04 ©Rinnai