Modulating Control Features - Dunkirk 95M-200 Control Manual And Troubleshooting Manual

Boiler Control Design
• Integrated modulating boiler control is designed for
central heating (CH) hot water boilers with modulating
fan and gas-air control.
• Modulation is based upon data relayed to control by
temperature sensors.
• Burner uses direct spark igniter (DSI).
• Modulating boiler control is intended for use in
combination with user interface display unit for both
information and operation.
• Control is designed for installation with conventional on/
off dry contact room thermostat.
• Control is able to provide hot water and outdoor reset
functions.
Main Controller Functions
Central Heat (CH): Control uses sensors on supply water,
return water and outside air to determine heat load of
heating system. Results in boiler supplying just enough
heat to satisfy demand which results in fewer overshoots
and less short cycling than conventional boiler.
Domestic Hot Water (DHW): When used in conjunction
with indirect hot water heater boiler has capability to
provide domestic hot water. An on/off dry contact aquastat
is used to activate call for domestic hot water.
Outdoor Reset: Control senses outside air temperature
using factory supplied, fi eld installed sensor. Controller
detects presence of sensor and reacts according to
parameters programmed into controller.
User Interface Display
User interface display allows installer and home owner to
scroll through control settings and customize boiler to heat
delivery system used in installation location. See "User
Interface Quick Reference" Section 10, page 21 for more
information on using and programming boiler control.

4 - MODULATING CONTROL FEATURES

IMPORTANT:
This boiler is equipped with a feature that saves energy
by reducing the boiler water temperature as the heating
load decreases. This feature is equipped with an override
which is provided primarily to permit the use of an external
energy management system that serves the same function.
This Override Must Not Be Used Unless At Least One Of The
Following Conditions Is True:
• An external energy management system is installed
that reduces the boiler water temperature as the
heating load decreases.
• This boiler is not used for any space heating.
• This boiler is part of a modular or multiple boiler
system having a total input of 300,000 BTU/hr or
greater.
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