AERCO BMK 2.0 LN Nat. Gas - Manual (Page 44)

SAFETY DEVICE TESTING
6-2
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)
RESET BUTTON FOR MANUAL
RESET TEMPERATURE LIMIT
SWITCH
HIGH LIMIT
ADJUSTABLE
TEMPERATURE
LIMIT SWITCH
MOUNTING PLATE
ON SHELL
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
Interlock. 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.