Benchmark 750/1000 Boiler
Installation, Operation & Maintenance Manual
CHAPTER 2 – INSTALLATION
OMM-0082_0J
AERCO International, Inc.
•
100 Oritani Dr.
•
Blauvelt, NY 10913
Page
31
of
192
GF-130
Ph.: 800-526-0288
05/21/2014
NOTE
Both the Delayed Interlock and Remote Interlock must be in the closed
position for the unit to fire.
2.10.12.2.1
Remote Interlock In (OUT & IN)
The remote interlock circuit is provided to remotely start (enable) and stop (disable) the unit
if desired. The circuit is 24 VAC and comes factory pre-wired closed (jumped).
2.10.12.2.2
Delayed Interlock In (OUT & IN)
The Delayed Interlock terminals can be used in one of two ways:
•
In conjunction with the optional external sequencing valve (see section 2.14 and
Chapter 10 – BST), a component of AERCO’s on-board Boiler Sequencing
Technology (BST) solution. By default a cable of the boiler’s wiring harness is
connected to these terminals. If BST is implemented, the other end of that cable is
connected to the sequencing valve.
•
If BST is
NOT
implemented, the second use is typically in conjunction with the
AUXILIARY RELAY CONTACTS described in section 2.10.14. This interlock circuit
is located in the purge section of the start string. It can be connected to the proving
device (end switch, flow switch etc.) of an auxiliary piece of equipment started by
the unit’s auxiliary relay. If the delayed interlock is connected to a proving device
that requires time to close (make), a time delay (AUX START ON DLY) that holds
the start sequence of the unit long enough for a proving switch to make (close) can
be programmed.
To use this option, you must disconnect the harness from the Delayed Interlock
terminals and connect the proving device in its place.
Should the proving switch not prove within the programmed time frame, the unit will
shut down. The AUX START ON DLY can be programmed from 0 to 120 seconds.
This option is located in the Configuration Menu (Chapter 3).
2.10.13 FAULT RELAY (NC, COM, & NO) Terminals
The fault relay is a single pole double throw (SPDT) relay having a normally open and normally
closed set of relay contacts that are rated for 5 amps at 120 VAC and 5 amps at 30 VDC. The
relay energizes when any fault condition occurs and remains energized until the fault is cleared
and the
CLEAR
button is depressed. The fault relay connections are shown in Figure 2-12.
2.10.14 AUX RELAY CONTACTS (NC, COM, & NO) Terminals
Each unit is equipped with a single pole double throw (SPDT) relay that is energized when there
is a demand for heat and de-energized after the demand for heat is satisfied. The relay is
provided for the control of auxiliary equipment, such as pumps and louvers, or can be used as a
unit status indictor (firing or not firing). Its contacts are rated for 120 VAC @ 5 amps. Refer to
Figure 2-12 to locate the AUX RELAY terminals for wiring connections.
2.11 FLUE GAS VENT INSTALLATION
AERCO Gas Fired Venting and Combustion Air Guide, GF-2050 must be consulted before any
flue or combustion air venting is designed or installed. Suitable, U/L approved, positive
pressure, watertight vent materials MUST be used for safety and UL certification. Because the
unit is capable of discharging low temperature exhaust gases, the flue must be pitched back
towards the unit a minimum of 1/4" per foot to avoid any condensate pooling and to allow for
proper drainage.
