AERCO BMK 2.0 LN Natural Gas 2008 - Manual (Page 44)

SAFETY DEVICE TESTING
3. Slowly open the ball valve at the high gas
pressure switch.
4. Start the unit in Manual mode at a firing rate
between 25 and 30%.
5. Using a flat-tip screwdriver, slowly increase
the gas pressure by turning the SSOV
regulator adjustment screw clockwise.
6. The unit should shut down and display a
HIGH GAS PRESSURE fault message
when the gas pressure exceeds 4.7” W.C.
The FAULT indicator should also start
flashing.
7. Reduce the gas pressure back to 2.7” W.C.
and replace the hex head cap on the SSOV
regulator.
8. Press the CLEAR button on the Control Box
to clear the fault.
9. The fault message should clear and the
FAULT indicator should go off. The unit
should restart.
10. Upon test completion, close the ball valve
and remove the manometer. Replace the
1/8“ plug removed in step 1.
6.4 LOW WATER LEVEL FAULT TEST
To simulate a low water level fault:
1. Set the ON/OFF switch on the Control Box
to the OFF position.
2. Close the water 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 necessary, the unit’s relief valve
may be opened to aid in draining.
4. Continue draining the unit until a LOW
WATER LEVEL fault message is displayed
and the FAULT indicator flashes.
5. Place the unit in the Manual Mode and raise
the firing rate above 30%.
6. Set the ON/OFF switch to the ON position.
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.
9. Open the water supply shut-off valve to the
unit to refill.
10. After the shell is full, press the LOW
WATER LEVEL RESET button to reset the
low water cutoff.
11. Press the CLEAR button to reset the
FAULT LED and clear the displayed error
message.
12. Set the ON/OFF switch to the ON position.
The unit is now ready for operation.
6.5 HIGH WATER TEMPERATURE
FAULT TEST
A high water temperature fault is simulated by
adjusting the automatic over-temperature switch.
This switch is accessible from the front of the
unit as shown in Figure 6-2.
1. Start the unit 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.
3. Once the adjustable over-temperature
switch setting is approximately at, or just
below, the actual outlet water temperature,
the unit should shut down. The FAULT
indicator should start flashing and a HIGH
WATER TEMP SWITCH OPEN fault
message should be displayed. It should not
be possible to restart the unit.
4. Reset the adjustable temperature limit
switch to its original setting.
5. The unit should start once the adjustable
temperature limit switch setting is above the
actual outlet water temperature.
6-2