QUICK REFERENCE
6.2
NORMAL OPERATION
The Qudos 28s and Qudos 28sP boilers feature a user display which shows actual flow
temperature. However, the display can also be used to show other information about the operation
of the boiler. Press the “
” button repeatedly until the display shows “SHP” and then press the
“ENTER” button, you will enter the installer information mode. Press the up arrow to the left of the
display once to show the first reading, flame current. Press the up arrow again to move on to the
next reading. The table below shows the values associated with consecutive up arrow button
press:
INSTALLER INFORMATION MODE (SHP)
The hours/days that the burner has been operated since manufacture of the PCB -
B:nn is thousands of hours plus nnn is single hours (ie 1345 hours would display as
B:01 and 234.
13
The hours that the boiler has been connected to a power supply since manufacture
of the PCB - P:nn is thousands of hours plus nnn is single hours (ie 1345 hours
would display as P:01 and 234.
12
The current boiler configuration - not used for general diagnostics
11
Active setpoint - the temperature that the boiler is attempting to reach and maintain
as determined by the user setting and/or the outside temperature sensor/advanced
controls.
10
Current fan speed (rpm) - display indicates a fan symbol.
9
DHW flow rate - not relevant for this model
8
Outside temperaure - display indicates a small graph on the bottom row. (NB: Only
relevant if an outside temperature sensor is detected)
7
System water pressure, in bar. (Maximum 2.7 bar, minimum 0.4 bar. The boiler will
shut down if the water pressure drops below 0.4 bar)
6
Actual Flue Temperature - display indicates the flame and fan symbols (NB: Flue
temperatures above 75C may cause reduced boiler output. Flue temperatures
above 80C will cause boiler lockout)
5
Actual DHW temperature - display indicates a tap symbol (NB Only relevant if the
DHW sensor option is connected)
4
Actual CH return temperature (maximum 72C) - display indicates a radiator symbol
and a “2”. (NB Flow temperatures more than 20C above return temperature may
lead to overheat and noise problems. Check the pump performance and the
system for blockages)
3
Actual CH flow temperature (maximum 84C) - display indicates a radiator symbol
and a “1”
2
The flame current (in micro amps) detected from the burner (should be <1 when off
and >2.5 when burner on. Low flame current readings suggest poor combustion
and may lead to flame lockouts. Check gas supply, air supply and combustion
setting.)
1
Meaning
Info No.
You can return to the normal display mode at any time by pressing the “Reset” button.
During normal operation the radiator symbol will indicate the mode of operation. If the radiator
symbol is not present then there is no demand on either SL1 or SL2. Other methods of placing a
demand on the boiler is via an Opentherm control, such as the Keston Room Controller, or a
0-10VDC input. Either alternative input is indicated by the inverted “T” symbol on the bottom row of
the display.
WD420/3/2007
Chapter 6 : Fault Finding
The Keston Qudos 28s & Qudos 28sP Boilers
Installation & Servicing Instructions
Page : 32
