Benchmark 750-3000 Boiler Installation & Startup Manual
SECTION 5 – SAFETY DEVICE TESTING
OMM-0121_D • GF-205 • 5/9/2019 Technical Support • (800) 526-0288 • Mon-Fri, 8 am - 5 pm EST Page 92 of 122
Figure 5-6b: Bare Boiler – Partial View – BMK 750/13000 Shown
Blower Proof Switch Test Instructions
1. Set the Controller’s On/Off switch to Off.
2. Remove the side and/or front panels to gain access to the Blower Proof Switch (see
Figures above for location).
3. Use a Phillips head screw drive to remove the front cover from the switch to reveal the
switch setting indicator dial (0.3 in the Figure below).
COVER WITH LABEL COVER REMOVED
Figure 5-7: Blower Proof Switch
4. Set the Controller’s On/Off switch to On and wait for the boiler to go into the Purge
sequence.
5. After about 5 seconds, with air flowing into the combustion chamber, slowly turn the dial
clock-wise (to higher value) until the unit trips off with an Air Flow Fault During Purge
message. Optionally, you could attach a manometer and measure the setting at the trip
point.
6. After the boiler shuts down, reset the dial indicator to its original position, shown on the
switch cover label, then replace the switch cover.
BLOWER PROOF
SWITCH
BLOCKED
INLET SWITCH
AIR/FUEL
VALVE
INDICATO
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