Installation / Operation Instruction Manual
21
Servicing Guide continued-
The following unusual situations will give reason for the alarm to sound:
If a High Pressure Control is installed, upon installation of the water
heater or occasions of re-starting water heater operation, if the inlet
supply line is closed (i.e. a shut-off valve), the high pressure may be
exceeded due to reasons of thermal expansion of the water.
If a Low Pressure Control is installed and if during the operation of
the water heater the inlet line is closed (i.e. a shut-of
f valve), a low
pressure condition can develop when water is allowed to exit through
the outlet connection.
If a Low Pressure Control is installed and if during the operation of
the water heater the inlet line is closed (i.e. a shut-off valve), a low
pressure condition can develop when water is removed through the
water heater drain valve.
Heating Element Sequencers
Heating element sequencers are available in order to stage the activation of
the heating elements thereby, reducing the inrush current to the water heater.
The sequenc
ers will control one or two contactor coils depending upon the
water heater voltage, phase, and KW.
One contactor will be energized immediately when there is heating demand,
the second contactor, controlled with a sequencer, will be activated
approximately 20 seconds later, and the third contactor will be activated in
another 20 seconds thereby, staging the three contactors over the 40 second
time period. The staging occurs in a similar manner for applications having
more than three contactors.
Refer to the Control Circuit Wiring Diagram for the specific application being
serviced.
Note: On the occasion of servicing the water heater where frequent restarts
in a short time interval are encountered (i.e. on, off, on, etc.), the timing
sequences will not begin until the sequencers have experienced a time
interval to reset.
Electrical Door Lock
An electrical door lock is offered in order to secure the access to the water
heater control cabinet. This device will lock the control cabinet door when the
120VAC control circuit voltage is applied to i
t.
Note: Once the door is opened, the water heater can be re-energized, if
necessary, for service diagnosis.