Winterwarm DHX User manual

EN - v2.3 / 07-2023
Installation manual
Air heater
Type DHX

Contents
1. Introduction 3
1.1. Symbols used in this manual 3
1.2. Warranty 3
2. Safety instructions 4
2.1. Installation 4
2.2. Use 4
2.3. Maintenance & Cleaning 4
2.4. Children and vulnerable users 5
3. Technical specifications 6
3.1. Performance 6
3.2. Gas types 6
3.3. Dimensions 8
4. Installation 9
4.1. Preparation 9
4.2. Positioning the air heater 9
4.3. Gas type & connection 9
4.4. Electrical connection 10
4.5. Room thermostat 10
5. Flue systems 12
6. Operating the air heater 13
6.1. Burner cycle 13
6.2. Minimum firing time 13
6.3. Summer ventilation 13
6.4. Overheating protection 13
6.5. Air passage check 14
6.6. Gas supply pressure 14
7. Commissioning the air heater 14
7.1. Adjusting the settings 14
7.2. Commissioning the air heater 14
8. Combustion settings 17
8.1. Adjusting the burner settings 17
8.2. Converting to another gas type 18
9. Troubleshooting 19
9.1. Volatile lock outs 19
9.2. Temporary errors 19
9.3. Warnings 19
9.4. Instructions 20
9.5. Further troubleshooting 21
10. Maintenance 22
10.1. Preparation 22
10.2. Basic maintenance 22
10.3. Maintenance of the burner unit 22
10.4. Extensive maintenance in poultry sheds 23
11. Electrical wiring diagram 24
12. Exploded view and spare parts 25
13. Disposal and recycling 26
14. Declaration of conformity 26

3INSTALLATION MANUAL AIR HEATER TYPE DHX
1. Introduction
This manual is intended for the gas, electrical and
mechanical installer.
This document gives instructions on how to use and
maintain the air heater. It is most important to follow the
instructions in this document for safe operation of this air
heater.
It is important to read this document before starting the
installation process. Store this document close to the air
heater for quick reference.
1.1. Symbols used in this manual
DANGER! Indicates a dangerous situation that would lead
to death or severe injury.
WARNING! Indicates a potentially dangerous situation
that could lead to death, severe injury or serious product
damage.
CAUTION! Indicates a potentially dangerous situation
that could lead to injury or product damage.
NOTICE Indicates important information that is not
directly related to safety.
1.2. Warranty
NOTICE Using, installing or maintaining this air heater in
any other way than described in this manual may cause
damage that voids the warranty.
NOTICE Failing to follow the safety instructions in this
manual can lead to damage to the air heater or the
installation and void the warranty.

4
2. Safety instructions
Always follow the safety instructions in this chapter when
installing, using or performing maintenance on this air
heater:
2.1. Installation
CAUTION! This air heater must be installed and
maintained by an authorized, qualified and competent
installer, using calibrated equipment.
NOTICE This air heater must be installed and maintained
in accordance with this manual, national and local building
regulations and local health and safety regulations.
2.1.1. Protection against dust
CAUTION! Cover the air heater while spreading sawdust
on the floor. This prevents large amounts of dust from
accumulating on the heater.
CAUTION! The air heater can be used in a dusty
environment (e.g. a poultry shed) if they are cleaned and
maintained more frequently.
2.1.2. Temperature
CAUTION! Do not install the heater in places where the
temperature can rise above 40°C. Higher temperatures
cause the internal components to degrade much faster.
2.1.3. Corrosive vapours
WARNING! Do not install the air heater in areas that
contain any corrosive or explosive vapours. Corrosive
vapours (e.g. containing Chlorine) that are sucked into the
air intake will cause corrosion of the heat exchanger and a
leakage of condensate and flue gas. This is also the case
for the room thermostat.
2.2. Use
CAUTION! Make sure the area around the air heater is
dry when performing maintenance on the air heater.
CAUTION! Always close the doors and inspection hatches
of the air heater, except when adjusting and checking the
appliance.
2.2.1. Maximum CO2concentrations
This air heater uses oxygen from the surrounding air for
the combustion process. CO2is formed and emitted as a
result. Too much CO2in the air may be harmful to people,
animals and crops.
DANGER! Never allow the CO2concentration to rise
above the values shown in the table below!
Maximum CO2concentration
Poultry shed 0.3% 3,000 ppm
Greenhouse 1% 10,000 ppm
DANGER! This air heater may emit carbon monoxide
(CO) when the oxygen level in the surrounding air is too
low. Carbon monoxide is extremely dangerous. Ensure
sucient ventilation to prevent this from happening.
WARNING! The minimal ventilation requirements for a
room in which this air heater is installed is 1000 m3/h for
each 100 kW of installed power.
2.3. Maintenance & Cleaning
Frequent maintenance and cleaning of the air heater is
necessary to ensure safe and proper operation. Failure
to do so could lead to damage to the heater or its
surroundings and void the warranty.
CAUTION! Air heaters installed in a dusty and/or wet
environment must be maintained and cleaned more
frequently.
CAUTION! Air heaters installed in poultry sheds must be
maintained and cleaned after every cycle.
CAUTION! Always have a service technician inspect
and maintain the heater every year for reliable and safe
operation.
2.3.1. Protection from water (IP class)
WARNING! Never use water when cleaning electrical
parts.
This air heater is protected against splash water and has
an IPX4D classification.
WARNING! Do not use a pressure washer to clean parts
that contain electronics, such as the electric motor or the
machine cover.

5INSTALLATION MANUAL AIR HEATER TYPE DHX
2.3.2. Disinfecting fluids
CAUTION! Some aggressive disinfection fluids can
damage the heater. When using such fluids, cover the
heater while disinfecting the shed.
2.4. Children and vulnerable users
WARNING! This air heater can be used by children aged
8 years and above and by persons with reduced physical,
sensory or mental capabilities or lack of experience and
knowledge, if they are supervised or instructed concerning
use of the appliance in a safe way and understand the
hazards involved.
WARNING! Children shall not play with the air heater.
WARNING! Children shall not clean and maintain this air
heater without supervision.

6
3. Technical specifications
3.1. Performance
Technical specification Unit Type DHX v5.1
DHX40 DHX75 DHX100 DHX120
Net nominal heat input kW 40.0 72.0 100.0 120.0
Heat output kW 40.0 72.0 100.0 120.0
Air output m3/h 3900 3900 5900 6800
Throw horizontal m 43 43 51 51
Gas connection G” 3/4" 3/4" 3/4" 3/4"
Electrical connection (50 Hz) V 230 230 230 230
Electrical power consumption kW 0.16 0.16 0.24 0.24
Stand-by electrical power
consumption
kW 4 4 4 4
Electrical current (max.) A 1.0 1.0 1.6 1.6
Protection class - IPX4D
Pressure switch point mbar 15 15 15 15
Sound level (at 8 m) dBA 65 65 70 70
Thermostat connection - 2-wire low voltage communication bus or ON/OFF 230 V
Net weight kg 35 35 45 45
3.2. Gas types
3.2.1. Natural gas G20
Specification Unit Natural gas G20
Nominal supply pressure mbar 20
Supply pressure (min. - max.) mbar 17-25
Gas category - II2H3B/P
DE: II2ELL3B/P
BE: I2Er
FR: II2Er3B/P
NL: II2EK3B/P
Pressure switch point mbar 15
Class - A3
Specification Unit DHX40 DHX75 DHX100 DHX120
Gas consumption m3/h 4.2 7.5 10.3 12.3
Burner injectors n x Ømm 1x 5.85 1x 8.5 1x 10.5 1x 12.0
Burner pressure mbar 8.0 6.5 6.3 6.0

7INSTALLATION MANUAL AIR HEATER TYPE DHX
3.2.2. Butane / LPG G30
Specification Unit Butane / LPG G30
Nominal supply pressure mbar 30 / 50
Supply pressure (min. - max.) mbar 20-50
Gas category - II2H3P B/P
NL: II2EK3B/P
DE: II2ELL3B/P
BE: I3B/P
FR: II2Er3B/P
PL: II2ELwLs3B/P
Class - A3
Specification Unit DHX40 DHX75 DHX100 DHX120
Gas consumption kg/h 4.0 6.0 8.0 9.5
Burner injectors n x Ømm 1 x 4.5 1x 5.85 1x 6.85 1x 7.8
Burner pressure mbar 8.5 8.0 9.0 8.1
3.2.3. Propane G31
Specification Unit Propane G31
Nominal supply pressure mbar 30 / 50
Supply pressure (min. - max.) mbar 20-50
Gas category - II2H3P B/P
NL: II2EK3B/P
DE: II2ELL3B/P
BE: I3B/P
FR: II2Er3P
PL: II2ELwLs3B/P
Class - A3
Specification Unit DHX40 DHX75 DHX100 DHX120
Gas consumption kg/h 3.8 5.7 7.9 9.5
Burner injectors n x Ømm 1 x 4.5 1x 5.85 1x 6.85 1x 7.8
Burner pressure mbar 11.5 10.7 11.5 10.7

8
3.3. Dimensions
The dimensions of this air heater can be found in figures 1 through 2.
Figure 1 - Dimensions of the DHX40 - DHX75
Figure 2 - Dimensions of the DHX100 - DHX120

9INSTALLATION MANUAL AIR HEATER TYPE DHX
4. Installation
4.1. Preparation
Before installation, please use the data badge to check:
• if the heater is in accordance with the order;
• if the heater is suitable for the local present
provisions (gas type, gas pressure, electrical supply
etc.)
Before leaving the factory, the air heater has been tested
for safety and has been set to the operating settings. It has
been configured for the type of gas that is stated on the
data badge. Should there be any doubt about the settings
that apply to your situation, please contact your supplier.
4.1.1. Standards
NOTICE The installation must comply with all applicable
local and national standards.
NOTICE The air heater must be installed in accordance
with the relevant requirements of the Gas Safety
regulations, Electrical installation regulations and or other
local regulations that may apply.
4.2. Positioning the air heater
Keep the following requirements in mind when choosing a
location to install your air heater:
WARNING! Never install an air heater close to flammable
materials.
• Keep sucient distance between the heater and
any obstructions. This is both for safety reasons
and to allow access for service and maintenance
(figure 3).
• Make sure the air flow to and from the heater is
free from obstacles at least 5 metres in front of the
heater. Also make sure the air intake is free from
obstacles.
• Make sure enough space remains to open the door
of the air heater.
• Make sure the wall can support the air heater.
Figure 3 - Minimum clearances around the air heater
4.2.1. Orientation
• Install the heater horizontally without an inclination
(figure 4).
Figure 4 - A correct and incorrect horizontal
orientation
4.3. Gas type & connection
The unit is suited for natural gas, propane or butane (LPG).
The specific gas type that a heater is set up for can be
found on the packaging labels and on the heater badge.
The heater can be converted to another gas type. Contact
your supplier for more information.
The working and standing supply pressure must be
a minimum of 17 mbar, and a maximum of 50 mbar,
measured at the inlet pressure nipple of the gas control in
the heater.
NOTICE The supply line’s manual isolation valve must be
placed within reach of the heater.
NOTICE All gas supply lines must be mounted without any
mechanical tension.
NOTICE Always clean the inside of a gas supply line
before connecting it to the air heater. Place a gas filter in
the supply line when needed.
CAUTION! When using pressures above 60 mbar to test
the supply lines, always close the manual isolation valve of
the air heater.

10
4.4. Electrical connection
The electrical installation must comply with local and
national requirements as well as IEE regulations.
4.4.1. Power supply
The air heater requires an earthed power supply of 230 V /
AC. The device is not phase-dependent. A supply of 400 V
/ AC + Neutral is optional. The control circuit is a two wire
230 V connection.
Figure 5 - The air heater's connection clamps
A supply cord with a connection plug is supplied with the
air heater.
NOTICE Make sure you do not damage the supply cord. A
damaged cable needs to be replaced by a qualified person
immediately.
4.4.2. Fuse
One fuse is present on the air heater’s control board (see
the electrical wiring diagram in §11.).
• When replacing this fuse, always use one of the
same type (5AT).
4.5. Room thermostat
The air heater can be controlled in two ways:
• by an ON/OFF signal 230 V;
• through a bus communication system with an
external interface.
4.5.1. Installation requirements bus communication
Following these requirements when placing the thermostat
to ensure the heater functions correctly:
• Make sure that air can circulate around the
thermostat.
• Make sure the sun does not shine directly upon the
thermostat.
• Do not place the thermostat on a cold wall.
• Place the thermostat on an inner wall free from
draught.
• Never place the thermostat within the throw of the
heater.
• Never mount the thermostat near the aerials of
internal communication networks. These emit
radiation that can disturb the thermostat. Keep
several meters distance.
In all cases, the communication between the heater
and the thermostat is based on a two wire, low-voltage
connection. (see the electrical wiring diagram in §11.).
Follow these instructions to prevent malfunction of the
installation and damage to the thermostat or air heater:
• Use a cable with the following specifications:
–Signal cable.
–Shielded and twisted.
–Minimum dimensions: 1 x 2 x Ø0.8 mm2.
–Maximum length: 200 m.
CAUTION! Keep the thermostat cable separated from the
mains cables.
CAUTION! Connect the cable’s earth shield only to the
earth terminal inside the air heater. Do not connect the
other end of the cable’s earth shield.
NOTICE A cable with a thickness of less than 0.8 mm will
result in a poor signal.
NOTICE A cable that is not shielded and twisted may
result in a disturbed communication in an EMC-unfriendly
environment.
4.5.2. Bus communication system installation
To connect the air heater to a bus communication system,
do the following:
1. Connect the two control wires to terminals 4 and
5 (see figure 6 or the electrical wiring diagram in
§11.).
2. Set the S1 and J14 switches on the control unit as
follows (figure 7 / 8):
a. Set S1 to 1.
b. Set J14 to 1.

11INSTALLATION MANUAL AIR HEATER TYPE DHX
NOTICE The air heater must be switched o when setting
the switches. Otherwise the settings will have no eect.
Figure 6 - Bus communication connection
1 2 3 4 5 6 7 8
ON
1 0
S1 J14
Figure 7 - Positions of the S1 and J14 switches
Figure 8 - Location of the S1 and J14 switches
4.5.3. Installation of multiple heaters on one control unit
An MTC or MTS room thermostat, or interface module can
control up to 8 air heaters. To connect the air heaters, do
the following (figure 9):
NOTICE This functionality does not apply to an ON/OFF
thermostat.
1. Connect the two wires of the thermostat to
terminals 4 and 5 of the first air heater.
2. Connect the first air heater to the second air heater.
3. Repeat for each subsequent air heater.
PE L5
4
N 5
45 45 4
22°C
L
N
PE L N
L
N
PE L N
L
N
PE L
N
L
N
123...8
22° C
L Neutal
4 5
L Neutal
4 5
L Neutal
4 5
1 2 3 4 5 6 7 8
ON
1 0
1 2 3 4 5 6 7 8
ON
1 0
S1 J14
1 2 3 4 5 6 7 8
ON
1 0
1
2
3
Figure 9 - Connection of multiple air heaters to a
modulating room thermostat
Each air heater needs an unique number to be recognised
by the room thermostat. This number can be set with the
J14 switch on the control unit of each air heater:
1. Set the S1 and J14 switches on the control unit as
follows (figure 10):
a. Set the S1 switch of the first air heater to 1.
b. Set the S1 switch of the other air heaters to 0.
c. Set the J14 switch of the first air heater to 1.
d. Set the J14 switch of the second air heater to
2, etc.
1 2 3 4 5 6 7 8
ON
10
1 2 3 4 5 6 7 8
ON
1 0
S1
J14
1 2 3 4 5 6 7 8
ON
10
Figure 10 - Positions of the S1 and J14 switches for the
first three air heaters in a system
NOTICE If the J14 switch of more than one air heater is
set to the same number, the system will not work.
NOTICE The air heater must be switched o when setting
the switches. Otherwise the settings will have no eect.

12
4.5.4. ON/OFF thermostat installation
To connect the air heater to an ON/OFF room thermostat,
do the following:
• Connect the two thermostat wires to terminal 6 and
7 (see figure 11 or the electrical wiring diagram in
§11.). This is a 230 V connection for the thermostat
signal.
Figure 11 - ON/OFF thermostat connection
5. Flue systems
To ensure safe and proper use, this air heater must be
connected to a flue system. This flue system must be
installed according to this manual as well as national and
local regulations. A flue system consists of a flue terminal,
piping and an optional condensate discharge system.
DANGER! Never allow the CO2concentration to rise
above the values shown in the table below!
Maximum CO2concentration
Poultry shed 0.3% 3,000 ppm
Greenhouse 1% 10,000 ppm
DANGER! This air heater may emit carbon monoxide
(CO) when the oxygen level in the surrounding air is too
low. Carbon monoxide is extremely dangerous. Ensure
sucient ventilation to prevent this from happening.
WARNING! The minimal ventilation requirements for a
room in which this air heater is installed is 1000 m3/h for
each 100 kW of installed power.

13INSTALLATION MANUAL AIR HEATER TYPE DHX
6. Operating the air heater
6.1. Burner cycle
The air heater’s display shows the current status of the
burner cycle (figure 12).
Figure 12 - Display of the air heater
Display Status Description Time
(seconds)
0Stand-by Waiting for heat demand. -
1 Reset Software reset. -
3 Pre-check Zero position check pressure
switch.
-
4 Pre-purge 10 seconds of pre-ventilation
by the fan. The pressure switch
is checked.
10
5 Pre-ignition Ignition without opening the
gas valve.
-
6 Ignition 5 seconds of ignition. The gas
valve opens.
-
7 Flame check The air heater checks if the
flame is present.
-
8 Burn The heater fires up and burns. 15
9 Minimum
(If
applicable)
Before the flame stops,
the burner will modulate to
minimum power.
-
10 Burner o The gas valve closes. The flame
stops.
-
11 Post purge System fan purges with fresh
air.
System fan cools the heat
exchanger.
40 - 120
P Anti-shuttle The heater can not generate
a heat demand during this
period.
1
F Ventilation Request to start (summer)
ventilation mode.
-
6.2. Minimum firing time
The heater will always fire for a minimum of 15 seconds,
even if the heat demand stops. This is to avoid a large
amount of start and stops.
NOTICE The heater will try to ignite 2 times before it stops
and gives an error.
Enter the times below in the barn computer to match the
heat demand and the fire cycle of the air heater.
Burner cycle phase Duration (seconds)
Minimum value Maximum value
Pre purge time 10 10
Firing time 15 3600*
Post purge time 40 120
*The air heater will restart after every hour.
6.3. Summer ventilation
The fan can be set to run in the summer. Follow the
instructions in the user manual of the Room thermostat or
the Bus communication system.
Summer ventilation can be activated on the air heater. For
further information, see §7.2.3..
6.4. Overheating protection
An NTC sensor is located near (or on) the heat exchanger.
This sensor monitors the heat exchanger temperature.
If the heat exchanger becomes too hot, this sensor will
cause the heating process to stop. Depending on the
temperature, the air heater performs the following actions:
• Step 1: Power reduction (when possible) (display:
A07).
• Step 2: Burner stop, followed by an automatic
restart when cooled down (display: E05 / E36).
• Step 3: Burner stop, followed by a Lock Out. A
manual reset is required. (display L15).
NOTICE A manual reset can be done on the electronic
circuit board or remotely with the special room thermostat.

14
6.5. Air passage check
The air heater is equipped with a vane switch to check the
passage of air through the heater. If the air passage is too
low, the heater will stop. Error L-14 will be shown on the
display.
6.6. Gas supply pressure
The gas supply pressure during stand-by and operation
should be between certain values, depending on the gas
type:
Natural gas: between 17 and 30 mbar.
Propane & Butane: between 25 and 57 mbar.
When the supply pressure is too low, the heater will
not work. Error A-09 will be shown on the display. The
setting from the pressure switch is shown in the technical
specifications (chapter 3.).
WARNING! When the supply pressure is too low, the
combustion gasses may become harmful for humans, as
well as animals and crops.
NOTICE When multiple heaters start at the same time,
the gas pressure may drop. When the gas pressure
restores, the heater will automatically restart.
Gas type Unit Gas supply pressure
Minimum value Maximum value
Natural gas mbar 17 30
Propane &
Butane
mbar 25 57
7. Commissioning the air heater
7.1. Adjusting the settings
Prior to packaging, the safety and functioning of each
air heater is checked in detail. It is also set to the right
combustion eciency.
In general, the heater does not need to be adjusted after
installation. It is only necessary to perform a functional
check and to obtain an optional flue gas analysis and
record it for later reference.
CAUTION! Use only calibrated instruments to adjust the
air heater.
CAUTION! Never carelessly turn the adjuster screws.
NOTICE Adjusting the control without checking the
burner pressure voids the warranty.
Only adjust the burner pressures if they dier more than
0,5 mbar from its setting.
7.2. Commissioning the air heater
Once the unit is installed according to this manual, the unit
can be commissioned. To do so, follow these instructions:
1. Make sure the gas supply pipe is clean, gas tight
and free from air.
2. Switch on the electric supply with the maintenance
switch.
You are now able to observe the first start-up and become
familiar with the functioning of the heater.
NOTICE If the gas line is not purged correctly, the heater
will attempt to start twice before going into a lock-out
condition. In this case, manual reset is necessary.
1. Instruct the end user of the about a safe use of the
air heater:
–The presence of gas
–The location of the manual gas valve
2. Instruct the end user about the operation of the
heater:
–Lock-out indication
–Reset
3. Instruct end user about the necessary
maintenance.
4. Leave this manual with the end user.

15INSTALLATION MANUAL AIR HEATER TYPE DHX
7.2.1. First use – thermostat
To commission the air heater via the room thermostat, do
the following:
• Put the thermostat in the highest position. The start
sequence is always the same.
The air heater will burn for the minimal firing time (see
§6.2. for more information).
7.2.2. First use - display
To commission the air heater via the display’s manual test
mode, do the following:
NOTICE The display’s manual test mode will only work for
maximum 10 minutes.
1. Press and hold the OK and (+) button for two
seconds (figure 13). The display will alternate
between Hi and St.
2. Press the OK button to confirm. The air heater will
start a burner cycle.
3. Press the (–) button until 0 is displayed to exit the
service. The air heater will always cool down the
heat exchanger for several minutes.
The test mode will automatically end after 10 minutes.
Figure 13 - Using the display
7.2.3. Manual operation
The air heater can be operated without an external
thermostat or signal. There are three modes available:
Heat demand deactivated
When this mode is activated, the air heater does not
respond to heat demands, except for heat demands
received through bus communication.
To activate the heat demand deactivated mode, do the
following:
1. Press the (+) and (-) buttons (figure 14)
simultaneously. The display shows a blinking 0.
2. Press the (+) button until the display shows a
blinking 6.
3. Press the OK button to deactivate the heat
demands. The display shows H.
12 hour burner cycle
When this mode is activated, the air heater starts a burner
cycle of 12 hours.
To activate a 12 hour burner cycle, do the following:
1. Press the (+) and (-) buttons (figure 14)
simultaneously. The display shows a blinking 0.
2. Press the (+) button twice until the display shows a
blinking 7.
3. Press the OK button to activate the 12 hour burner
cycle mode. The display shows H2.

16
Summer ventilation
When this mode is activated, the air heater ventilates
continuously. The air heater does respond to heat
demands. When a heat demand ends, the ventilation
function continues.
To activate the summer ventilation, do the following:
1. Press the (+) and (-) buttons (figure 14)
simultaneously. The display shows a blinking 0.
2. Press the (+) button three times until the display
shows a blinking 8.
3. Press the OK button to activate the summer
ventilation. The display shows H3.
Exit a mode
To deactivate a mode, do the following:
1. Press the (+) and (-) buttons (figure 14)
simultaneously.
2. Press the (-) button until the display shows 0.
3. Press the OK button to deactivate the mode.
Figure 14 - Using the display

17INSTALLATION MANUAL AIR HEATER TYPE DHX
8. Combustion settings
In principle, it is not necessary to adjust the control shortly
after commissioning the air heater. When the control does
have to be adjusted after a period of use or after installing
a new heater, this must be done by a qualified person
using calibrated equipment.
DANGER! A poor adjustment can lead to overheating of
the air heater and/or production of toxic carbon monoxide.
8.1. Adjusting the burner settings
The flow of gas to the burner is controlled with a gas valve.
The valve must be set to the correct burner pressure. The
minimum gas pressure switch is mounted on the right side
of the measuring point (figure 15).
Figure 15 - Main parts of the gas valve
1 Measuring point of gas supply pressure.
2 Measuring point of burner pressure.
3 Adjuster screw for burner pressure.
To adjust the burner pressure, do the following:
1. Switch o the air heater.
2. Connect the pressure meter to the measuring point
(figure 15 - 2).
3. Switch on the air heater and start heating.
4. Check whether the burner pressure is equal to the
nominal burner pressure for this air heater (see
§3.2.).
5. Record the measured value as a reference for the
next measurement.
6. If the burner pressure does not correspond with the
specified value, turn the adjuster screw (figure 15 -
3) to the specified value.
8.1.1. Measuring the CO(2) values
Adjusting the burner pressure using the adjusting screw
is sucient. Optionally, you can check the CO and CO2
values, which can be done as follows.
Figure 16 - Measuring combustion values with a probe
To measure the CO and CO2values, do the following:
1. Switch on the air heater and allow it to heat for
about 5 minutes.
2. Measure the CO value.
3. Measure the CO2percentage in the flue gas.
4. Record the CO and the CO2values as a reference
for the next measurement.
5. If the CO value exceeds 15 ppm:
or
If the CO2value does not correspond to the
specified percentage (table A):
a. Check the burner pressure air inlet opening of
the system fan to see if the CO2value deviates
by more than 1%.
b. Measure the burner pressure (figure 15 - 2).
c. Check whether the gas pipe diameter is too
small (gas pressure too low).
d. Repeat steps 2 till 4.
Table A shows the approximate nominal CO2percentages
for the DHX models (air temperature 20°C):
Nominal CO2percentage
Gas type DHX40 DHX75 DHX100 DHX120
High calorific gas (G20) 7.3% 8.1% 8.0% 7.1%
Low calorific gas (G25) 7.8% 8.7% 8.3% 7.7%
Butane (G30) 8.1% 9.6% 9.7% 8.6%
Propane (G31) 8.5% 9.8% 9.4% 8.9%
Table A - CO2values per gas type and heater model

18
8.2. Converting to another gas type
To change the gas type of the heater, the gas injector has
to be changed (figure 17 - 6).
Figure 17 - The head of the burner unit
CAUTION! For safety reasons, the manufacturer
recommends that the air heater is converted to another
gas type only by the manufacturer, its representative or
a qualified service technician. Contact your supplier for
more information.
To change the gas injector, do the following:
1. Open the inspection hatch.
2. Remove the gas pipe by unscrewing the
compression fitting (figure 17 - 4).
3. Remove the two connecting boots (figure 17 - 9)
from the ignition electrode by gently pulling at the
cables.
4. Unscrew the four nuts that connect the burner unit
to the air inlet.
5. Remove the burner unit from the air heater.
6. Disassemble the burner unit:
a. Remove the stabilizer (figure 17 - 7) from the
injector (figure 17 - 6).
b. Remove the flange from the injector by
unscrewing the injector’s nut.
7. Install the new injector.
8. Reassemble the burner unit.
9. Select the correct injector diameter and burner
pressure (see §8.1.).
10. Change the labels on the air heater with ones that
have the correct values for the new gas type.
11. When the air heater has been reassembled and
cleaned, perform the following checks:
a. Open the manual gas valve and check if the
gas supply line does not leak.
b. If the heater has been moved, check if the
supply lines are connected properly.
WARNING! Gas supply lines that are not connected
properly can slip o and create a fire hazard.
c. Check if the wiring is secured properly.
12. Perform all checks that are performed during the
installation of the air heater (see §7.2.):
a. Measure the burner pressure.
b. Measure the combustion values.
c. Check the general heater operation.

19INSTALLATION MANUAL AIR HEATER TYPE DHX
9. Troubleshooting
If the air heater malfunctions, first check if the problem is
caused by external circumstances (e.g. no supply power).
If the problem is not caused by external circumstances,
use the tables and instructions in this chapter to fix the air
heater.
NOTICE Please remember the built in waiting times of
the air heater; the signals of the LED’s and the code on the
display. Do not react too soon.
9.1. Volatile lock outs
The table below describes the volatile lock outs that can
occur. These can only be reset by hand.
Display Error type Description Case #
L-0 Internal error Internal error 13
L-1 Ignition error Flame lasts only 5
seconds after ignition
1
No flame after ignition 2
L-2 and 3 Internal error Internal error 13
L-4 E-error E-error for more than 24
hours
12
L-8 to 12 Internal error Internal error 13
L-13 Vane switch error Vane switch is closed
while fan isn't running
17
L-14 Vane switch error Vane switch does not
close when the fan should
run
18
L-15 Overheating Heat exchange sensor is
overheated
3
L-17 to 19 Internal error Internal error 13
L-20 Flame error Flame detected after
closing the gas valve
15
L-21 Flame error Flame detected before
opening the gas valve.
16
L-22 Flame error Flame failure during
burning
5
L-25 Sensor error Heat exchange sensor
failure
4
L-27 to 31 Internal error Internal error 13
L-32 Sensor error Heat exchange sensor
failure
4
L-33 to 38 Internal error Internal error 13
L-39 Vane switch error Vane switch is closed
while fan isn't running
17
L-40 and
41
Vane switch error Vane switch does not
close when the fan should
run
18
L-43 Overheating Heat exchange sensor is
overheated too often
3
9.2. Temporary errors
The table below describes the temporary errors that can
occur. These will disappear automatically after the cause
has been resolved.
Display Error type Description Case #
E-00 to 04 Internal error Internal error 13
E-05 Overheating Heat exchange sensor is
overheated
3
E-06 to 13 Internal error Internal error 13
E-14 Flame error Flame detected when
there shouldn’t be one
16
E-15 to 20 Internal error Internal error 13
E-21 and 22 Heat exchanger
sensor error
Heat exchanger sensor
not detected
4
E-27 and 28 Heat exchanger
sensor error
Heat exchanger sensor
short-circuit
4
E-34 Reset button
error
Too many reset actions in
a short timespan
9
E-36 Overheating Heat exchange sensor is
overheated
3
E-38 and 39 Heat exchanger
sensor error
Heat exchanger sensor
not detected
4
E-47 and 48 Heat exchanger
sensor error
Heat exchange sensor
short-circuit
4
E-49 to 64 Internal error Internal error 13
E-65 Voltage too low Supply voltage is too low
for over 1 minute
E-66 Voltage too high Supply voltage is too high
for over 1 minute
E-67 Pressure switch
error
Too many pressure switch
errors
11
E-69 Configuration
error
Heater configuration error 19
9.3. Warnings
The table below describes the temporary warnings that
can occur. The heater may still be working, or stops until
the cause has been resolved.
Display Error type Description Case #
A-02 Configuration
error
Heater configuration error 19
A-07 Overheating Heat exchange sensor is
almost overheated
3
A-09 Gas pressure There is not enough gas
pressure.

20
9.4. Instructions
After identifying the problem, use the Case number to find
the possible cause in this paragraph.
Case 1: Flame lasts only 5 seconds after ignition.
• The flame is not detected:
–Check the ignition/ionisation cable and the
electrode. The cable should have a resistance
of 1 kΩ.
• The air heater is not earthed properly.
• The circuit board is defective.
Case 2: No flame after ignition.
• There is not enough gas pressure.
• The gas mixture is too poor:
–Adjust the gas valve (see §8.1.).
• The gas valve does not open:
–During ignition, check for a 230 V voltage on
the valve.
• Check if the ignition electrode sparks. If not:
–Check the cable and electrode and replace
them when damaged. Optionally, verify the
ionization value (see §9.5.2.).
–Check the burner control unit and replace it
when it does not give a spark output.
• Check the ignition transformer
Case 3: Heat exchange sensor or flue sensor is overheated.
• Check if the connectors J12 and J6 are plugged in
correctly and if the connection J12[1-4] (optional
overheating protection) is closed.
• Check if the system fan supplies enough air.
• Check the settings of the gas valve. The heater may
be overfired. If so:
–Adjust the burner pressure.
Case 4: Heat exchange sensor or flue sensor not detected,
or short circuit.
NOTICE L-25 refers to the heat exchange sensor. L-26
refers to the flue sensor, if applicable.
• The heat exchange sensor consists of two internal
sensors. The readings of these sensors may dier
too much:
–Measure the resistance of each sensor. The
resistance should be 20 KΩ at 25 °C and 25
KΩ at 20 °C.
–If the measured values dier too much,
replace the sensor.
Case 5: Too many flame failures while burning.
• The gas supply is not constant. This results in a
drop in gas supply pressure while burning and
causes the flame to extinguish.
–Check the gas supply pressure while the
heater is burning.
• Recirculation of flue gas. Due to a problem with the
flue terminal the flue gas is sucked back into the air
inlet. This results into a lack of oxygen and causes
the flame to stop.
–Check the flue system and fresh air supply.
Only certified, original parts should be used.
Case 9: Too many reset actions in a short timespan.
• This error will disappear after some time or if the
main power is disconnected for a while.
Case 12: E-error for more than 24 hours.
• Switch the air heater o and on and check the error
code.
Case 13: Internal error.
• Isolate the electrical supply and reenergise. If this
does not help:
–Replace the burner control unit.
Case 15: Flame detected after closing the gas valve.
• Check if the gas valve closes too slow. If so:
–Replace the gas valve.
• Check if the ionisation electrode is wet. If so:
–Dry, clean or replace the electrode.
Case 16: Flame detected before opening the gas valve.
• Check if there really is a flame before ignition. If so:
–Replace the gas valve.
• Check if the ionisation electrode is wet. If so:
–Dry, clean or replace the electrode.
Case 17: Vane switch is closed while fan isn't running
• Check if the vane switch is stuck and cannot go
into the rest position. If so:
–Clean or replace the vane switch.
Case 18: Vane switch does not close when the fan should
run
• Check if the fan runs. If so:
–Check if the vane switch is stuck and cannot
go into closed position. If so:
–Clean or replace the vane switch.
• If the fan does not run, check if the fan motor is
powered. If not:
–Replace the fan motor or the capacitor.