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SERVICE PROCEDURE RE-IV
Light Duty Commercial
Thermostat Testing
WARNING
High voltage exposure. Use caution to avoid
personal injury during this procedure.
D
ouble Element, Non-Simultaneous, Single Phase
O
peration.
W
ater In Tank Is Cold With Power ON.
1. This procedure assumes line voltage, ECO and
elements are in working order.
2. Turn power “ON” to water heater.
3. Set multi-meter to “Volts AC”.
4. Check across terminals L4 and T2 of
upper thermostat (see illustration 29).
A) Rated voltage NOT present,
Recheck ECO (see page 14). If
ECO is okay, replace thermostat.
B) Rated voltage IS present,
proceed to next step.
5. Check across element terminals
(see illustration 30).
A) Rated voltage NOT present,
check wire connections from
thermostat to element.
B) Rated voltage IS present,
Repeat element testing
see page 15.
Illustration 29 Illustration 30
Tank Does Not Deliver Enough Hot Water.
1. This procedure assumes line voltage, ECO and elements are in
working order.
2. Turn power “ON” to water heater and set multi-meter to “Volts AC”
3. Adjust temperature setting of upper & lower thermostat to the
Highest setting. Water temperature in tank must be below thermostat
setting for this test.
4. See illustration 29 above. Check voltage across terminals L4 & T2 of
upper thermostat.
A) Rated voltage IS present, okay, upper thermostat is calling
for heat. Go to step 5 below.
B) Rated voltage NOT present, replace upper thermostat.
5. Adjust temperature setting of upper thermostat to the minimum
setting. Water temperature in tank must be above thermostat setting
for this test.
6. Check voltage across terminals L3 & T4 of upper
thermostat (see illustration 31).
A) Rated voltage NOT present, replace upper thermostat.
B) Rated voltage IS present, upper thermostat is okay. Go to
step 7 on next page.
Illustration 31
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