Combustion From Outside The Building; Combustion Air From Inside The Building; Ducted Combustion Air; Sequencing Valve Installation - Aerco BENCHMARK 2500DF User Manual

Benchmark 2500DF-3000DF Installation, Operation & Maintenance Manual

2.12.1 Combustion From Outside the Building

Air supplied from outside the building must be provided through two permanent openings. For each unit
these two openings must have a free area of not less than one square inch for each 4000 BTUs input of
the equipment or 750 square inches of free area. 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.

2.12.2 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 BTUH of total input or 3000 square inches of free area. The free area must take into account any
restrictions, such as louvers.

2.13 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.
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. See the AERCO Benchmark Venting
and Combustion Air Guide, GF-2050. When using the boiler in a ducted combustion air configuration,
each unit must have a minimum 8 inch diameter connection at the unit.

2.14 SEQUENCING VALVE INSTALLATION

All Benchmark units are shipped with a connection for an optional motorized external sequencing valve
(p/n 92084-TAB) included in the shipping container. This valve is an integral component of the AERCO's
on-board Boiler Sequencing Technology (BST) solution. BST allows sites with multiple boilers to have
one boiler, acting as a "master" to manage the other boilers at the site in such a way that the efficiency of
the entire boiler array is maximized.
The implementation of BST, and the installation and use of this valve is optional.
The boiler is pre-wired to accept the sequencing valve. Installation consists of installing the sequencing
valve in the hot water outlet pipe, and then connecting it into the shell harness, as described below.
When operated with the BST system, the Master controls its own isolation valve and sends signals to the
slave units to open or close their isolation valves. After the boiler load is satisfied, the isolation valve
opens for a programmed interval (default = 1 minute) before closing. When the system load is satisfied,
the BST system will open the isolation valves for all of the boilers.
When the Sequencing Isolation Valve is used, the AUX START ON DLY
in the Configuration menu must be set to at least 120 seconds. The
Sequencing Isolation Valve control is only available when BST is
enabled. Refer to section 2.10.12.2 and Table 3-4 in section 3-6 and
Chapter 10.
OMM-0099_0A
GF-145
CHAPTER 2 – INSTALLATION
NOTE
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913
Ph.: 800-526-0288
Page 31 of 234
PR1: 05/21/2014