Benchmark 750-6000 with Edge [i]: Install-Startup Manual
SECTION 2
– INSTALLATION
OMM-
144_B • GF-217 • 5/25/2020 Technical Support • (800) 526-0288 • Mon-Fri, 8 am - 5 pm EST Page
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2.13 COMBUSTION AIR
The
Benchmark Venting and Combustion Air Guide
, TAG-0022 (GF-2050) MUST be consulted
before any inlet air venting is designed or installed. Air supply is a direct requirement of ANSI
223.1, NFPA-54, CSA B149.1 and local codes. These codes should be consulted before a
permanent design is determined.
The combustion air must be free of chlorine, halogenated hydrocarbons, other chemicals that
can become hazardous when used in gas-fired equipment and other combustion products.
Common sources of these compounds are swimming pools, degreasing compounds, plastic
processing, and refrigerants. Whenever the environment contains these types of chemicals,
combustion air MUST be supplied from a clean area outdoors for the protection and longevity of
the equipment and warranty validation.
If combustion air is supplied directly to the unit(s) though air duct(s), see section 2.13.1 below.
If combustion air is not supplied through air ducts, it must be supplied to the unit(s) through two
permanent openings. These two openings must have a free area of
not less than one square
inch (6.5 cm
2
) for each 4000 BTUs (1.17 kW) input
for each unit
. The free area must take
into account restrictions such as louvers and bird screens.
For Canada installations, refer to the requirements specified in CSA B149.1-10, sections 8.4.1
and 8.4.3.
2.13.1 DUCTED COMBUSTION AIR
For ducted combustion air installations, the air ductwork must be attached directly to the air inlet
connection on the sheet metal enclosure. Consult the
Benchmark Venting and Combustion Air
Guide
, TAG-0022 (GF-2050) when designing combustion air ducting.
In a ducted combustion air application, the combustion air ducting pressure losses must be
taken into account when calculating the total maximum allowable venting run. When using the
unit in a ducted combustion air configuration, the minimum diameter connection at the unit is:
TABLE 2-4: Air Duct Minimum Diameter
Benchmark Model
Duct Diameter
BMK750
– BMK1500
6 inch (15.2 cm) diameter connection
BMK2000
– BMK3000
8 inch (20.3 cm) diameter connection
BMK4000 and 5000N
10 inch (25.4 cm) diameter connection
BMK5000 & BMK6000
14 inch (35.6 cm) diameter connection
2.14 BENCHMARK PUMP RELAY
Benchmark units include a pump relay (P/N
69102-2
for
BMK750 & 1000,
69102-3
for BMK1500
- 6000) as standard equipment. The pump relay allows the user to turn a pump on/off and
open/close a motorized valve as the boiler cycles on and off on demand. The Pump Delay Timer
feature allows the user to keep the pump running and keep the motorized valve open for up to 30
minutes after the boiler has shut down and the demand is satisfied.
The pump relay is attached to the outside of the power box, as shown below. Boilers equipped
with the pump relay have a label on the power box cover adjacent to the relay.
