Benchmark 5000-6000 Boiler Installation & Startup Manual
SECTION 3:
START SEQUENCE
OMM-0123_E
• GF-207 • 12/17/2019 Technical Support • (800) 526-0288 • Mon-Fri, 8 am - 5 pm EST Page
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of
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When there is a demand for heat, the following events will occur:
Start Sequence
1. The
DEMAND
LED status indicator will light.
2. The unit checks to ensure that the Proof of Closure (POC) switch in the downstream Safety
Shut-Off Valve (SSOV) is closed. See Figure 3-1 for SSOV location.
Figure 3-1: SSOV Location
3. With all required safety device switches closed, a purge cycle will be initiated and the
following events will occur:
a. The Blower relay energizes and turns on the blower.
b. The Air/Fuel Valve rotates to the full-open purge position and closes purge position
switch. The dial on the Air/Fuel Valve (Figure 3-2) will read 100 to indicate that it is
full-open (100%).
c. The
VALVE POSITION
bargraph will show 100%.
Figure 3-2: Air/Fuel Valve In Purge Position
STEPPER
MOTOR
TO BLOWER
AIR IN
UPSTREAM
SSOV
TO AIR/FUEL
VALVE
GAS INLET
MANUAL SHUT-
OFF VALVE
DOWNSTREAM
SSOV WITH
POC
HIGH GAS
PRESSURE SWITCH
- BMK 6000
:
10.5” W.C., 2.6 kPa
- BMK 5000
:
11.0” W.C., 2.7 kPa
UPSTREAM LOW GAS
PRESSURE SWITCH
- BMK 6000
:
8.5” W.C., 2.1 kPa
- BMK 5000
:
8.0” W.C., 2.0 kPa
