AERCO Esteem O&M Manual - Manual (Page 64)

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The boiler can directly accept an analog 0-10
VDC signal to control the firing rate from an
external modulating boiler controller.
Wiring the Modulating Controller
Run two 18 gauge wires from the external
modulating boiler controllers 0-10 VDC boiler
output to the external input terminals on the
low voltage terminal strip inside the boiler.
(see boiler wiring diagram, Figure 20 page
34). This signal will both enable and modulate
the boiler. No wiring is required at the thermo-
stat (T-T) terminals 7 and 8 of the boiler.
N
OTICE
Ensure that the polarity of the con-
nections from the external modulating
boiler controller to the boiler is correct.
Reversed polarity could lead to erratic
and/or no response from the boiler con-
troller.
Parameter Adjustment
The Esteem 399 Low NOx MCBA control
module must be programmed to accept the
0-10 VDC signal from the external modulating
boiler control.
CH Operating Signal Section
(Parameter 45)
Follow the procedure for entering the MCBA
Access Code on page 56, and then change the
setting of Parameter 45 from the factory set-
ting of 00 to 02.
N
OTICE
Ensure that Parameter 4 is set above
the highest setpoint of the external
modulating control. Parameter 4 is a
boiler high temperature limit when us-
ing an external modulating controller.
Programming of External Modulating
Control
The external modulating control must be pro-
grammed to send 1.8 VDC to enable the boiler
and run it at low fire, and 10 VDC to run the
boiler at high fire. Once the control enables the
boiler, it must wait 2 minutes to allow the burn-
er to stabilize before modulating the boiler.
Factory Setting Revised Setting
00 02
Chapter 14 External Modulating Control
GF-125