SAFETY DEVICE TESTING
6-2
4. Reconnect the wire previously removed from
the high gas pressure switch and depress
the
CLEAR
button.
5. The unit should restart.
6.4 LOW WATER LEVEL FAULT TEST
1. Place the
ON/OFF
switch in the
OFF
position.
2. Close shut-off valves in the supply and
return piping to the unit.
3. Slowly open the drain valve on the rear of
the unit. If it is necessary to vent the unit to
aid in draining, the unit’s relief valve may be
opened.
4. Drain the unit until the
LOW WATER LEVEL
fault message is displayed and the
FAULT
LED flashes.
5. Place the unit in the Manual Mode and raise
the firing rate above 25%.
6. Set the
ON/OFF
switch to
ON
. The
READY
light should remain off and the unit should
not start. If the unit does start, shut the unit
off immediately and refer fault to qualified
service personnel.
7. Close the drain and pressure relief valve
used in draining the unit.
8. Open the water shut-off valve in the return
piping to the unit to fill the shell.
9. Open the water shut-off valve in the supply
piping to the unit.
10. After the shell is full, press the
LOW
WATER LEVEL RESET
button to reset the
low water cutoff. Press the
CLEAR
switch
to reset the
FAULT
LED and clear the
displayed error message.
11. Set the
ON/OFF
switch to the
ON
position.
The unit is now ready for operation.
6.5 WATER TEMPERATURE FAULT
TEST
1. In the normal operating mode, allow the unit
to stabilize at its setpoint.
2. Lower the adjustable temperature limit
switch setting to match the displayed
OUTLET TEMPERATURE. (See Fig. 6.2).
ADJUSTABLE
TEMPERATURE LIMIT SWITCH
RESET BUTTON
FOR MANUAL RESET
TEMPERATURE
LIMIT SWITCH
MOUNTING PLATE
ON SHELL
HIGH LIMIT
Figure 6.2
Temperature Limit Switch Setting
3. Once the adjustable limit switch setting is
approximately at, or just below, the actual
outlet water temperature, the unit should
shut down. The
FAULT
LED should be
flashing and the message
HIGH WATER
TEMP SWITCH OPEN
should be displayed.
The unit should not start.
4. Reset the adjustable temperature limit
switch setting to its prior setting.
5. The unit should start once the adjustable
temperature limit switch setting is above the
actual outlet water temperature.
6.6 INTERLOCK TESTS
The unit is equipped with two interlock circuits
called the Remote Interlock and Delayed Inter-
lock. Terminal connections for these circuits are
located in the I/O Box and are labeled REMOTE
INTL’K IN and DELAYED INTL’K IN. These
circuits can shut down the unit in the event that
an interlock is opened. These interlocks are
shipped from the factory jumpered (closed).
However, each of these interlocks may be
utilized in the field as a remote stop and start, an
emergency cut-off, or to prove that a device
such as a pump gas booster, or louver is
operational.
Summary of Contents for AERCO Benchmark 2.0
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