AERCO BMK 3.0 LN Dual-Fuel Series Gas Fired Low NOx Boiler System - Manual (Page 54)

SAFETY DEVICE TESTING
6-6
of closure switches. The proof of closure switch
circuit is checked as follows:
1. Set the unit’s
ON/OFF switch to the OFF
position.
2. Place the unit in Manual Mode and set the
valve position between 25% and 30%
3. Refer to Figure 6-1 and locate downstream
SSOV #1(natural gas).
4. Remove the cover from SSOV #1 by
loosening the screw shown in Figure 6-4. Lift
off the cover to access the terminal wiring
connections.
5. Disconnect wire #148 from SSOV #1 to
“open” the proof of closure switch circuit.
When wire #148 is disconnected, it opens
the proof of closure switch circuit for both
the natural gas and propane downstream
SSOVs.
6. The unit should fault and display SSOV
SWITCH OPEN.
7. Replace wire #148 and press the CLEAR
button.
8. Set the ON/OFF switch to ON to start the
unit.
9. Remove the wire again when the unit
reaches the purge cycle and PURGING is
displayed.
10. The unit should shut down and display
SSOV FAULT DURING PURGE.
11. Replace the wire on SSOV #1 and press the
CLEAR button. The unit should restart.
ACTUATOR
COVER
SCREW
SSOV #1
ACTUATOR
COVER
Figure 6-4
SSOV #1 Actuator Cover Location
6.12 PURGE SWITCH OPEN DURING
PURGE
The Purge Switch (and Ignition Switch) is
located on the Air/Fuel Valve. To check the
switch, proceed as follows:
1. Set the unit’s ON/OFF switch to the
OFF
position. Place the unit in manual mode and
set the fire rate between 25% and 30%.
2. Remove the Air/Fuel Valve cover by rotating
the cover counterclockwise to unlock it and
then lift up (see Figure 6-5).
3. Remove one of the two wires (#171 or #172)
from the Purge Switch (Figure 6-6).
4. Initiate a unit start sequence.
5. The unit should begin it’s start sequence,
then shut down and display PRG SWITCH
OPEN DURING PURGE.
6. Replace the wire on the Purge Switch and
depress the CLEAR button. The unit should
restart.
6.13 IGNITION SWITCH OPEN DURING
IGNITION
The Ignition Switch (and the Purge Switch) is
located on the Air/Fuel Valve. To check the
switch, proceed as follows:
1. Set the unit’s
ON/OFF switch to the OFF
position.
2. Place the unit in Manual Mode and set the
valve position between 25% and 30%.
3. Remove the Air/Fuel Valve cover (Figure
6-5) by rotating the cover counterclockwise
to unlock and lift up to remove.
4. Remove one of the two wires (#169 or #170)
from the Ignition Switch (Figure 6-6).
5. Initiate a unit start sequence.
6. The unit should begin it’s start sequence
and then shut down and display IGN
SWITCH OPEN DURING IGNITION.
7. Replace the wire on the Ignition Switch and
press the CLEAR button. The unit should
restart.