Benchmark 6000 Boiler Installation, Operation & Maintenance Manual
CHAPTER 2 – INSTALLATION
Page
32
of
210
AERCO International, Inc.
•
100 Oritani Dr.
•
Blauvelt, NY 10913
OMM-0086_0D
03/20/14
Ph.: 800-526-0288
GF-133
•
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 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 2-13.
2.10.14 AUX.RELAY Terminals
Each unit is equipped with a single pole double throw (SPDT) auxiliary 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 2-13 to locate the AUX.RELAY terminals (N.C., COM, & N.O.) for wiring
connections.
2.11 FLUE GAS VENT INSTALLATION
The 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.
While there is a positive flue pressure during operation, the combined pressure drop of vent and
combustion air systems must not exceed 140 equivalent feet or 1.9” W.C. Fittings as well as
pipe lengths must be calculated as part of the equivalent length. For a natural draft installation
the draft must not exceed - 0.25” W.C. These factors must be planned into the vent installation. If
the maximum allowable equivalent lengths of piping are exceeded, the unit will not operate
properly or reliably.
