Watts AERCO Benchmark OMM-0136 - Page 18

Benchmark Platinum-Edge [II]: Operation-Service Manual
SECTION 3 - START SEQUENCE
OMM-0137_E • GF-211 • 12/13/2019 Technical Support • (800) 526-0288 • Mon-Fri, 8 am - 5 pm EST Page 18 of 153
Start Sequence
Figure 3-1e: BMK5000-6000: SSOV Location – BMK6000 Shown
3. The Auxiliary Delay occurs for a configurable length of time and the Delayed Interlocks are
closed.
4. Once all required safety device switches are closed, a purge cycle is initiated, and the
following events 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 3-2a and 3-2b) will read 100 to indicate
that it is full-open (100%).
c. The Fire Rate bar graph on the Controller’s front face shows 100%.
Figure 3-2a: BMK750 & 1000 Air/Fuel Valve in Purge Position
STEPPER MOTOR
TO
BLOWER
AIR INLET
100
UPSTREAM
SSOV
TO AIR/FUEL
VALVE
GAS INLET
MANUAL SHUT-
OFF VALVE
DOWNSTREAM
SSOV WITH
POC
HIGH GAS
PRESSURE SWITCH
- BMK6000: 10.5” W.C., 2.6 kPa
- BMK5000: 11.0” W.C., 2.7 kPa
UPSTREAM LOW GAS
PRESSURE SWITCH
- BMK6000: 8.5” W.C., 2.1 kPa
- BMK5000: 8.0” W.C., 2.0 kPa