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Benchmark 5000-6000 Boiler Installation & Startup Manual
SECTION 2: INSTALLATION
NOTE:
Both the Delayed Interlock and Remote Interlock must be in the closed position for the unit to
fire.
2.11.12.1 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).
2.11.12.2 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 2.15:
Sequencing Isolation Valve Installation, below, and Section 6: Boiler Sequencing
Technology), a component of AERCO's on-board Boiler Sequencing Technology (BST)
solution. A cable of the boiler's wiring harness is connected to these terminals on all
units; 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 2.11.14, below. 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 (see Section 2.6: CONFIGURATION Menu, item 16, in the Benchmark
5000 – 6000 Operation and Maintenance Guide, OMM-0124 (GF-208).
2.11.13 Fault Relay (NC, COM, & NO)
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 2-14.
2.11.14 Auxiliary Relay Contacts (NC, COM, & NO)
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 2-14 to locate the AUXILIARY RELAY terminals for wiring connections.
OMM-0123_E • GF-207 • 12/17/2019
Technical Support • (800) 526-0288 • Mon-Fri, 8 am - 5 pm EST
Page 30 of 95
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