Combustion Air From Outside The Building; Combustion Air From Inside The Building; Sealed Combustion; Temporary Combustion Air Filtering During Construction - Watts AERCO Benchmark 2.0LN User Manual

GF-127
OMM-0052_0E
The more common methods of supplying combustion air are outlined below. For more
information concerning combustion air, refer to the AERCO Benchmark Venting and Combus-
tion Air Guide, GF-2050.
2.12.1

Combustion Air From Outside the Building

Air supplied from outside the building must be provided through two permanent openings. Each
opening must have a free area of not less than one square inch for each 4000 BTU/H boiler
input. 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, 8.4.1 and 8.4.3.
2.12.2

Combustion Air From Inside The Building

When combustion air is provided from within the building, it must be supplied through two
permanent openings in an interior wall. Each opening must have a free area of not less than
one square inch per 1000 BTU/H of total boiler input. The free area must take into account any
restrictions such as louvers.
2.12.3

Sealed Combustion

The AERCO Benchmark 2.0LN Boiler is UL listed for 100%-sealed combustion. For sealed
combustion installations, the screen on the air inlet duct of the unit must be removed. The inlet
air ductwork must then be attached directly to the unit's air inlet.
In a sealed combustion air application, the combustion air ducting pressure losses must be
taken into account when calculating the total maximum allowable venting run. See the AERCO
Benchmark Venting and Combustion Air Guide, GF-2050. When using the boiler in a sealed
combustion air configuration, each unit must have a minimum 8 inch diameter connection at the
unit.
2.12.4

Temporary Combustion Air Filtering During Construction

When the Benchmark 2.0LN Boiler is used to provide heat temporarily during ongoing building
construction, accumulated drywall dust, sawdust and similar particles can accumulate in the
unit's combustion air intake filter and block combustion air flow. In these situations, AERCO
recommends that a disposable air intake filter be installed, temporarily, above the boiler
combustion air inlet.
AERCO recommends that the temporary air filter be cut from a McMaster-Carr part no.
2122K315 Polyester Air Filter Roll Tackfield, ½" thick, 16" wide, or equivalent. Cover the
Benchmark 2.0LN air inlet with the blue side of the filter material facing outward to hold the dust
on the outside surface. Maximize the surface area of the filter covering the 8" diameter opening
by creating a dome out of the filter material.
Cover the flared duct opening with the blue side facing outward. During construction check the
filter for dust accumulation and replace it when the accumulation becomes noticeable.

2.13 BENCHMARK PUMP RELAY OPTION

An optional Benchmark 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 Benchmark pump relay (SPDT) contact is rated for:
•
10 A Resistive @ 277 VAC/28 VDC
•
1/3 HP N/O @ 120/240 VAC
•
1/6 HP N/C @ 120/240 VAC
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 • Ph: 800-526-0288
PR2: 04/22/13
Benchmark 2.0LN Dual-Fuel Low NOx Boiler
Operation and Maintenance Manual
CHAPTER 2: INSTALLATION
Page 25 of 158