1
Service
10
Service Manual
1
Service
General Operation
How the boiler operates
The Knight wall mount boiler uses an advanced stainless steel
heat exchanger and an electronic control module that allows
fully condensing operation. The blower pulls in gas and air
and pushes flue products out of the boiler through the heat
exchanger and flue piping. The control module regulates
blower speed to control boiler firing rate. The gas valve
senses the amount of air flowing into the boiler and allows
only the right amount of gas to flow.
How the control module operates
The Knight wall mount control module receives input from
boiler sensors. The control module activates and controls
the blower and gas valve to regulate heat input and switches
boiler, DHW and system pumps on and off as needed. The
user/installer programs the module to meet system needs by
adjusting control parameters. These parameters set operating
temperatures and boiler operating modes. Boiler operation
can be based on boiler outlet water temperature, boiler return
water temperature or system supply temperature, depending
on the parameter setting.
Sequence of operation
Table 1-1 shows control module normal sequences of
operation for space heating and DHW operation. The
combined operation sequence is for a typical application,
programmed to provide DHW priority.
Access modes
User
The user can adjust space heating and tank target temperatures
by pressing the NAVIGATION dial when “
SETPOINTS” is
flashing at the bottom of the display. The date and time, and
the temperature units can also be changed.
Installer
Most parameters are available only to the installer, accessible
only by entering the installer password (5309).
For accessing, adjusting, and saving parameters, reference
Tables 1-2 and 1-3 on pages 13 - 14 of this manual.
Summary of Contents for WH 399
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