Knight 285, Service Manual

1  

Service

18

Service Manual

1  

Service 

SH Differential

The SH differential sets how many degrees below the turn off
temperature the temperature has to go before the boiler will
turn on. This parameter can only be changed by the installer
by accessing parameter 

B5

. The temperature range of this

parameter is 0°F to 86°F. The default value is 20°F.

C: Data logging

Hours running SH

The hours running SH parameter shows the total number of
hours the boiler has been in the SH firing position. This
parameter can be viewed by the user and the installer by
accessing parameter 

C1

.

Hours running DHW

The hours running DHW parameter shows the total number
of hours the boiler has been in the DHW firing position. This
parameter can be viewed by the user and the installer by
accessing parameter 

C2

.

Ignition attempts

The ignition attempts parameter shows the total number of
times the boiler has attempted to fire. This parameter can be
viewed by the user and the installer by accessing parameter

C3

.

Show last 10 errors

The control will log the 10 most current errors with the date
and time the error occurred. This parameter can be viewed
by the user and the installer by accessing parameter 

C4

.

D: Functions

Reset last 10 errors

The reset last 10 errors parameter allows the error counter to
be reset to 0. This parameter can only be cleared by the
installer by accessing parameter 

D1

. Once accessed, press the

RESET key to clear the counter.

Service mode delay

By pressing the pin button on the front of the display for five
(5) seconds, the control will be placed in Service Mode. This
will override all other heat demands. The Service Mode
allows the installer to set the unit to either maximum firing
rate or minimum firing rate for the purpose of combustion
analysis. The delay sets the length of time the boiler will stay
in the Service Mode if no keys have been pressed before going
back to its original state. This parameter can only be changed
by the installer by accessing parameter 

D2

. The time range of

this parameter is 0 to 40 minutes.

The default value is

20 minutes.

E: DHW settings

DHW boiler set point

When a DHW call for heat becomes active, the control will
use the DHW boiler set point to determine the firing rate of
the boiler based on the actual water temperature.

This

parameter can be changed by the installer by accessing
parameter 

E1

. The temperature range of this parameter is

50°F to 190°F. The default value is 180°F.

SH/DHW switching time

The SH/DHW switching time parameter sets the length of
time the control will stay in DHW Mode when a SH call has
been received. After this time period has expired the control
will revert to SH Mode. If a DHW call is still active the timer
will reset. After the time period has expired the control will
revert back to DHW Mode. This will continue until one of
the demands has been satisfied.

This parameter can be

changed by the installer by accessing parameter 

E2

. The time

range of this parameter is 10 minutes to 240 minutes. The
default value is 30 minutes.

F: Outdoor air reset  

Outdoor air reset operation

When the outdoor air sensor is installed, the control will
calculate the water temperature set point based on the
outdoor air temperature. As the outdoor air temperature
drops the water temperature set point increases. This feature
allows the boiler to be more efficient in periods of mild
weather, see FIG. 1 on page 19.

Minimum air temperature

When the outdoor air temperature drops to or below this
point, the water temperature will be at its maximum setting
(FIG. 1). However, if the user set point is set lower, the water
temperature will be limited by the user set point instead. This
parameter can be changed by the installer by accessing
parameter 

F1

. The temperature range of this parameter is -

30°F to 90°F. The default value is 25°F.

Maximum air temperature

When the outdoor air temperature rises to or above this
point, the water temperature will be at its minimum setting
(FIG. 1). This parameter can be changed by the installer by
accessing parameter 

F2

.

The temperature range of this

parameter is -30°F to 90°F. The default value is 70°F.