Baxi MULTI-HEAT User manual

EN/137466/0/14-06-2002
INSTRUCTIONS MULTI-HEAT
INSTRUCTION FOR INSTALLATION AND USE OF
BAXI MULTI-HEAT
List of sections
Section
Operating and owner instructions 1
Possibilities for automation 2
Installation instructions 3
Technical data and wiring diagram 4
Setup and test report 5

It is hereby declared that below BAXI product:
Multi-Heat
complies with the EEC directives mentioned below.

●
Council Directive 89/336/EEC of 3 May 1989 on the approximation of the laws of the Member States relating to electromagnetic
compatibility and 92/31/EEC and 93/68/EEC)
●
Council Directive 73/23/EEC of 19 February 1973 on the harmonization of the laws of Member States relating to electrical equipment
designed for use within certain voltage limits and 93/68/EEC
●
Directive 98/37/EEC of the European Parliament and of the Council of 22 June 1998 on the approximation of the laws of the Member
States relating to machinery
The photograph shows MULTI-HEAT 2.5
Page 1
List of contents
This instruction is divided into sections - the figure numbers refer to the corresponding section
Section
1 USE AND THE USER'S TASK / RESPONSIBILITY / POSSIBILITIES
1.1 OVERVIEW OF THE BOILER AND THE EQUIPMENT
1.2 RESPONSIBILITY AND SAFETY
1.3 DESCRIPTION OF OPERATION
1.4 STARTING UP THE BOILER
1.5 IGNITION
1.6 EXTINGUISHING
1.7 BOILER AND RETURN TEMPERATURE
1.8 DAILY FIRING
1.9 USER EXPERIENCES
1.10 RECOMMENDED ADJUSTMENT OF OPERATION
1.11 CLEANING THE BOILER
1.12 OPERATING THE PUMP
1.13 OPERATING THE MIXING VALVE (SHUNT VALVE) - (EXTRA EQUIPMENT)
1.14 USE OF PRESSURE GAGE
1.15 FILLING UP WITH WATER
1.16 SAFETY SPRINKLER DEVICE
1.17 TROUBLE SHOOTING
1.18 PREVENTIVE MAINTENANCE
1.19 SUMMER STOP
2 AUTOMATION
3 INSTALLATION INSTRUCTIONS
3.1 STANDARD EQUIPMENT AND OPTIONAL EXTRAS
3.2 ARRANGEMENT CONDITIONS - AIR SUPPLY
3.3 CHIMNEY CONNECTION
3.4 EXPANSION, SAFETY VALVES AND PUMP CONNECTION
3.5 ELECTRICITY CONNECTION
3.6 ASSEMBLY GUIDELINES
3.7 SYSTEM DIAGRAM
4 TECHNICAL DATA AND ELECTRICAL DIAGRAMS
4.1 TECHNICAL DATA
4.2 ELECTRICAL DIAGRAM

5 GENERAL DELIVERY SURVEY REPORT FOR BOILER SYSTEM
5.1 MEASURED AND ADJUSTED VALUES
Due reservations are made regarding construction amendments and possible printing errors.
Page 2
1 Use and the user's task / responsibility / possibilities
1.1 Overview of the boiler and the equipment
1. Control Panel

2. Cleaning door, top
3. Combustion chamber
4. Burner
5. Cleaning door, bottom
6. Observation flap
7. Air apertures for the combustion
8. Blow-off faucet (on type 2.5 this is placed between the fire box and the
hopper)
8a. Delivery screw for air chamber (on type 2.5 this is placed directly over
the bottom frame on the right-hand side.
9. Ignition / striking arc
10. Cleaning opening (for hopper)
11. Fuel worm conveyor/auger (transports the fuel inwards)
12. Back-burn safety valve
13. Blower (provides air for the combustion)
14. Stirrer/agitator (only for the version firing with wood chips)
15. Air intake (there is one of these on both sides)
16. Cleaning flap (there is one of these on both sides)
17. Covers for hopper (reversible)

18. Smoke nozzle
19. Flow and return
Fig. 1.1 (This shows MULTI-HEAT 4,0)
Page 3
1.1.1 Fuel forms (see also page 1)
Wood pellets
MULTI-HEAT is delivered as a standard for firing with wood pellets. MULTI-HEAT 1.5 is principally
designed for wood pellets.
The wood pellets must be pure wood.
1. Without additives or chemical or synthetic binders
2. Water content below 10%
3. Max. 1% dirt/dust
4. Calorific value approx. 5 kW/kg
To determine whether the wood pellets are suitable:
1. The smell must be as for pure wood
2. The smell when burning must be as for pure wood
3. The colour must be as for wood, without particles of a clear of other colour such as white, green or
blue.
Please ask your supplier for a description of contents
Grain (barley and wheat)
When firing with grain the co-delivered worm conveyor/auger extension must be mounted in order to
counteract the inconveniences caused by cinders which can be formed in the combustion chamber. The
boiler is tested with barley and wheat with a water/moisture content of 15%.
Corn (maize)
When firing with corn (maize) the co-delivered worm conveyor/auger extension must be mounted
in order to counteract the inconveniences caused by cinders which can be formed in the combustion
chamber. The boiler is tested in USA with maize with a water/ moisture content of 15% or less.
Wood chips

The version for firing with wood chips (model F) has a hopper in the stirrer or agitator system which
transports the fuel to the worm conveyor/auger. We recommend a chip size of 5-30 mm with a water/
moisture content of 25% or less.
Change-over
When changing fuel-type it is important to switch over the boiler corresponding to the correct equipment
and the new operation setting.
Use of equipment
Wood
pellets Grain Corn (Maize) Wood chips
worm conveyor/auger
extension ÷++÷
Stirrer / agitator ÷ ÷ ÷ +
+ = must be used
÷ = must not be used
Usage of other and less suitable fuel types for MULTI-HEAT - over and above the wood pellets indicated
above, grain (wheat and barley), corn (maize) as well as wood chips can result in less problem-free
operation, more work for the user and possibly a greater fuel consumption. Consult the factory for advice
with regard to the possibilities of using other types of fuel.
1.1.2 Function (Refer if necessary to fig. 1.1)
The fuel worm conveyor/auger (11) "screws" the fuel into the boiler's combustion chamber (4).
The combustion air is supplied via the built-in blower (13) down through holes (7) at the back and up into
the fuel.
The flue gas passes upwards through the boiler's combustion chamber (3) and via a well-dimensioned
number of horizontal fire tubes with stirrers or turbo-mixers, the flue gas is returned to the return/cleaning
chamber (16) and leaves the boiler via the vertical smoke nozzle (18).
Page 4
Safety: Insofar as the fire moves backwards into the fuel supply pipe, the retrograde combustion (back
burn) safety device (12) will extinguish the fire with water.
If the fire goes out, a built-in smoke gas sensor will turn off the boiler and sound an alarm. The boiler
must not run with the doors to the hopper door (17) open.

The control (1) is an electronically built-up 2-stage control. The 2 stages can be set according to the heat
requirement: 30-100%. It is also possible to make a setting for high or low output.
The boiler will run at a high output until the set temperature is close to being achieved.
Then the automatic control will switch to reduced output. If the temperature then drops slightly again, the
automatic control will couple up to full output again.
When the set temperature has been achieved, the blower will be switched off and the automatic control
will switch over to intermittent operation. This means that the fire is kept alight by adding a little fuel at
considerable intervals and simultaneously briefly setting the blower in action.
1.1.3 Service and guarantees:
The guarantee is described more closely in the BAXI Guarantee Certificate which is delivered together
with the boiler.
Complaints: You ought always refer to the fitter or dealer who has installed / delivered the central heating
boiler for you. After this, the fitter / dealer will, if necessary, pass on your complaint to the factory.
However, complaints can also be made directly to the factory.
1.2 Responsibility and safety
1.2.1 Responsibility The user is responsible for correct operation of the boiler and that the firing
guidelines from BAXI A/S are followed. Circumvention of the guidelines can, amongst other things,
result in a lower useful effect and increased environmental strain, as it is not possible to achieve the clean
smoke gases which are aimed at. Furthermore, incorrect operation can reduce the lifetime of the boiler.
Correct operation (and installation) are the best guarantee for a well-functioning boiler with a long
lifetime and a good immediate environment.
It is a precondition that the user has the necessary will and correct attitude to firing with wood pellets,
grain, maize, wood chips, and such like since, after all, it is necessary to carry a piece of work in order to
"harvest the fruits" of this environmentally friendly and economically advantageous form of heating.
1.2.2 Safety: If faults or deficiencies are ascertained, these must be rectified as quickly as possible by a
heating and ventilation fitter.
Outlet pipes, ventilation channels, fresh air openings, etc must not be closed or blocked.
The water supply for the boiler's retrograde combustion (back burn) safety device must not be shut off.
Inflammable liquids or easily combustible materials must not come dangerously close to the boiler.
All stoking must take place via the stoker system.
1.2.3 Maintenance: If irregularities on the system's safety valves, expansion tanks or automatics are
ascertained, the owner / user must immediately ensure that the equipment in question is examined and put
right by an expert.
The owner / user must ensure that fitted safety valves, if any, are not blocked up by incrustation and
suchlike.

It is the responsibility of the owner or user that the boiler and equipment, if any, are cleaned and
maintained in accordance with:
- normal practice
- indications in this instruction
- instructions for equipment / accessories, if any
- as well as conditions described in the appurtenant guarantee
certificate
(See section 1.18 Preventive maintenance as well as the boiler's guarantee certificate).
Page 5
1.3 Description of operation
Side
A. Display 7
B. Menu 7

C. Form of operation 7
D. Ebullition thermostat 10
E. ON / OFF button - ignite / extinguish Error!
Unknown switch argument. 6
F. Alarm reset - cancel alarm 9
G. Manual worm conveyor/auger - forwards 8
H. Manual worm conveyor/auger - backwards 8
I. Light diodes 7
J. Set = boiler temperature. 6
K. High output 8
L. Low output 8
M. Firing at intervals 8
P. Pump 10
R. REG Error! Unknown switch argument. 7
Fig. 1.3
Remember: Always ensure that you have a pen and paper ready every time you adjust the
settings on the control. Suggestions for tables can be seen on the last page of this
instruction.
When an adjustment is made on a setting, the information regarding this will
be shown in the display for approx. 10 seconds after the last adjustment or until
another function is carried out.

(E) Ignite takes place by pressing the ON/OFF button (E) and this will be displayed in the light
diode above the button..
(J) Boiler temp. is adjusted by keeping set (J) pressed in and simultaneously pressing on + or – on REG
(R). The temperature can be adjusted from 60 to 85°C. The ideal temperature is 80°C
since it is "good for the boiler" to have a comparatively high temperature. (When "set"
is pressed, the diode will light up - "set" and the adjusted temperature is shown on the
display.
Page 6
(R) Regulation
Here the adjustable parameters can be adjusted up and down in value.
(B) Menu With this button it is possible to switch between which of the 4 temperatures you wish
to have shown in the display. However, in the set-up menu, it is used to "step" through
the set-up points. - (See temperature display on the next page). This is also used for
programming, as shown on page Error! Unknown switch argument. Error! Unknown
switch argument.9.
(A) (I) Temp. indication - with the menu button (B) it is possible to set the desired temperature in the
display (A).
•Every time you press the menu button this will switch to the next temperature
(displayed on the light diodes (I)).
The temperatures which can be shown are:

•Supply pipe
temperature = boiler temperature.
•Return temperature = return temperature to the boiler
•Set temperature = the set, desired boiler temperature
•Smoke temperature = the temperature in the boiler's fire tubes
(Symbols for 02% and the ventilator's actual % only apply for the model with oxygen
control. – see separate instruction.
When everything is in full swing it is a good idea to have the smoke temperature displayed
so that you can keep an eye on what the smoke temperature is so that it is possible to see
whether the boiler needs to be cleaned.
Neither must the smoke temperature be too low since this can cause condensation in the
chimney.
How low the temperature is depends on the chimney, but temperatures below 120°C are
not normally to be recommended..
Note: If you press on one of the buttons (J - M), the adjusted value will be shown for 5
seconds - after which the value which you have chosen will be shown once again.
(C) Operation
form Here it is possible to switch automatic mode (Fixed-diode switched off) or constant high or low output mode (Fixed-diode lit up)
Choose with the button (C) between 2-step operation = light diode switched off) or
constant operation (light diode lit up).
There are three possibilities which can be set by pressing button (C):
1. 2-step operation = no light above the button
2. Fixed high output = light above button and light on row 100%

3. Fixed low output = light above button and light on row 30-100%
The greatest advantage can be achieved by choosing the form of operation called 2-
step operation..
Here, the boiler must run at a high output until the temperature is just 3 degrees below
the desired temperature, and then switched down to a low output. The operation will thus
continue on a low output until the temperature is achieved.
If the temperature cannot be maintained with a low output, the boiler will once again
switch to a high output when the temperature has dropped to 6 degrees below the
adjustment value.
2-step operation:
During 2-step operation, the lowest smoke temperature and the highest useful effect are
achieved.
Letters in brackets () see fig. 1.3
Page 7
(K) High Output This is set by means of the 2 push buttons above the 100% symbol.
The lowest button is used to set the number of seconds between each worm conveyor/
auger delivery - this can be set between 5 and 30 seconds. This setting is shown in the
display. (Press in and hold "SEC" and adjust up or down by pressing on + or – on REG
(R).
In the same manner, the uppermost button is used to set the blower's air quantity from 0
to 100, where 100 corresponds to maximum air quantity. The adjustment is shown in the
display.
The firing quantity and the air quantity must be adjusted according to each other.
It is possible to choose how big a "high output" you want to have. High output does not
necessarily need to be the boiler's maximum output, but it must just be greater than the
heat requirement of the house.
Suggestions for adjustment - see, if necessary, section 1.10 - recommended adjustment
of the control.
(L) Low Output This is set by means of the 2 push buttons above the 30-100% symbol.

The lowest button is used to set the number of seconds between each worm conveyor/
auger delivery - this can be set between 10 and 60 seconds, but never below the setting
of the high output. The setting is shown in the display. Press in and hold "SEC" and
adjust up or down by means of pressing on + or –. Using the uppermost button, set the
blower's air quantity from 0 to 100, where 100 corresponds to maximum air quantity.
The adjustment is shown in the display.
The firing quantity and the air quantity must be adjusted according to each other.
Minimum output is 30% of full output. See also technical data.
Suggestions for adjustment - see, if necessary, section 1.10 - recommended adjustment
of the control.
(M) Firing at
intervals This is set by means of the push button (M)
Set the number of minutes between each worm conveyor/auger delivery. This is only
active when the boiler temperature is rising. Set between 1 and 60 min so that the
fire can just be kept alight without firing so much that the temperature rises - this is
experience value.
Suggestions for adjustment - see, if necessary, section 1.10 - recommended adjustment
of the control.
(G) Manual worm conveyor - forward
This takes place by pressing on the symbol for the fuel worm conveyor/auger with the
arrow key to the right. As long as the key is activated, the worm conveyor/auger will run
inwards. However, this will not take place when the hopper is open.
(H) Manual worm conveyor/auger- backward
This takes place by pressing on the symbol for the worm conveyor/auger with the
arrow key to the left. As long as this key is activated, the worm conveyor/auger will
run outwards. However, not when the hopper door is open. Furthermore, the worm
conveyor/ auger can only run for 3 seconds if the key is depressed for a longer time.
Bogstav i parentes () se fig. 1.3
Page 8

(F) Alarm re-set- Here, the alarm is re-set. If there is no alarm, use the button to come into the set-up
menu (but simultaneously with the (C)-button). The following are the alarms which can
appear:
A-1
There is no fire! The smoke temperature has been below 100°C during operation for
more than 30 minutes of operation, or after intermittent firing and starting up. Check the
smoke gas sensor and remove any coating.
A-2
The ebullition thermostat (D) is switched off. This can be reconnected by pressing when
the cover is removed. (Situated in the boiler's operation panel). The circuit breaker on
the back of the control panel (see 4.2 - electrical diagram) has blown.
A-3
The motor protection for the worm conveyor/auger has failed. This can be reconnected
when the motor is no longer over-burdened.
A-4
The flow temperature has exceeded 94°C.
A-5
Error during communication with the more sensitive parts of the control, i.e. the
program cannot be saved or read.
The programming situation arises when the ON/OFF button (E) has been switched off
by keeping the alarm re-set (F) and the operation form (C) buttons pressed down for
3 seconds. Then 3 horizontal lines will appear in the display and it will be ready for
programming.
Programming -
By "stepping" with the menu key, the data which have been set can be seen.

By pressing on + or - on REG (R), the minimum air quantity of the blower is adjusted.
Possible settings are 10-20-30-40-50.
The factory setting is (- 20) = 20%
(–XX)
When the desired value is shown in the display, save by pressing button (C).
Here, the worm conveyor/auger's running-in time is adjusted at "high output" - i.e. the
time which the worm conveyor/auger is running each time. Adjustment area: 0.1-6.0
corresponding to 0.1-6.0 seconds.
(HX.X)
Save with button (C).
Here, the worm conveyor/auger's adjustment time is adjusted at "low output" - i.e. the
time which the worm conveyor/auger is running each time. Adjustment area: 0.1-6.0,
corresponding to 0.1-6.0 seconds.
(LX.X)
Factory setting::
MULTI-HEAT
Type HX.X (high output) LX.X (low output)
1,5 H1,7 = 1,7 sec. L1,7 = 1,7 sec.
2,5 H0,5 = 0,5 sec. L0,3 = 0,3 sec.
4,0 H1,0 = 1,0 sec. L0,6 = 0,6 sec.
Here, the time which the blower is to run with maximum air quantity is adjusted when
the fuel worm conveyor/auger is in the interval situation.
(PXX)
(Possible setting: 0-10 seconds).

Factory setting (P05) = 5 seconds
The settings can be changed by pressing on + or minus on REG (R).
By means of the operation form button (C), the desired setting can be saved, and it is
possible to "step" further in the menu.
Step through the program with the menu button (B).
NB: You must "step" at least one level further before you "save". (If you do not do this,
the latest figure will not be saved)
Save data New data are saved by closing down and pressing the ON/OFF button (E).
Regret If, nevertheless, you do not want to save the new input data which have been entered,
you can regret by pressing the alarm/reset button (F).
Letters in brackets () see fig. 1.3
Page 9
(D) Ebullition
thermostat If the boiler temperature reaches up to approx. 100°C the ebullition thermostat will switch off the boiler, and the display will show (A-2). In order to reconnect, unscrew
the protective cap and press in the pin which has sprung. The alarm is then re-set by
pressing in (F).
(P) Pump The circulation pump for the heating plant can be ignited (light diode = ON) or switched
off.
1.4 Starting up the boiler
●Prior to starting up the boiler, it is necessary to ensure that there is sufficient water in the system.

●Prior to starting up the boiler, it is necessary to ensure that the water supply is connected to the
retrograde combustion (back burn) valve. (See section 1.16 - retrograde combustion (back burn)
valve).
●It is necessary to ensure that the ignition/fuel arc (pos. 9, fig. 1.1) is pushed right back.
●The hopper lid must be closed, since this hinders retrograde combustion (back burn). The packing
in the hopper lid must be closed and air-tight, and this must be controlled regularly (once per
year).
The built-in micro-switch likewise ensures that the boiler cannot run without the lid being closed.
Suggested settings are indicated on page 13.
●You ought to aim that the smoke temperature does not exceed 220°C.
●You must likewise ensure that the smoke temperature does not fall so low that condensation is
formed in the chimney. (Remove 1-2 turbulators if necessary.)
This temperature is dependent on the chimney's diameter and insulation.
The recommended smoke gas temperature setting for firing with grain is min. 130°C.
●There is a built-in alarm in the control which will indicate an alarm if the smoke temperature is
below 100° C for more than 30 min.
●If the house's chimney is such that condensation forms, some turbulators can be removed
to increase the smoke gas temperature in order to counter the condensation. The boiler has,
however, been tested and approved with all turbulators installed. Efficiency is reduced and fuel
consumption increased when turbulators are removed.
1.5 Ignition
1.5.1 Wood chips and pellets:
Move the fuel forwards so that there is a pile of about 5-6 handfuls inside the combustion chamber and
the control is set on OFF.
Pour lighter fuel over the fuel and ignite.
When the fuel is ignited and in flame, with an open door, set the control to ON, then close the door and
the boiler is in operation.
(Here it is possible to open the hopper door slightly so that the combustion worm conveyor/auger does
not start up immediately). When a proper "blaze" has been established in the combustion chamber,
carefully close the hopper door again.
NB: Never leave the boiler with an open hopper door.

If the boiler is fitted with oxygen control, set the control to OFF (button E), and a "sea of flames" can
be created by pressing fan symbols K and L simultaneously. The fan will run at a lower speed and the
augur will not start. When combustion is well underway, set the control to ON (button E).
1.5.2 Corn/grain:
Move the fuel towards the opening of the combustion chamber and switch the control to OFF.
Insert 5-6 handfuls of easily combustible material (e.g. wood chips or pellets) into the combustion
chamber at the fuel entrance. Then follow the instructions above.
Page 10
1.6 Extinguishing
When extinguishing, set the control to OFF. Cinders and live coals must be removed from the combustion
chamber.
1.7 Boiler and return temperature
As already mentioned in section 1.3, we suggest that the boiler temperature should be kept at 80°C.
In order to minimise the risk of corrosion in the boiler, the return temperature ought to be min. 60°C.
1.8 Daily firing
1.8.1 Running in period
●In the beginning, it is recommended that you should regularly (daily) inspect your boiler system
and check the fuel hopper, and fill this up, if necessary.
●Check flow temperature, return temperature, as well as smoke temperature. See, amongst other
things, sections 1.3 to 1.7.
●At the beginning, you ought regularly to open the lowest door and check the quantity of ash in
the bottom of the combustion chamber, in order to ascertain how often it is necessary to remove
the ash. (Let a little bit of the ash remain so that the air holes in the bottom of the combustion
chamber are just covered by ash).
1.8.1 Adjustment
The boiler ought to be adjusted first at high output (K) which only ought to be slightly higher than the
maximum heating requirement of the house. The recommended heat loss in an elderly house is approx.
80-160 W/m2 and in a more modern house, approx. 50 W/m2.
After this, set at low output - see technical data and use the recommended adjustment data from the PC-
diskette from BAXI A/S.
The colour of the flame ought to be yellow and slightly bluish.

●If the flame is short and blue, either the interval time or the air quantity must be reduced.
●If the flame is long and reddish-yellow, either the interval time or the air quantity must be
reduced.
Colour of the flue gas
●If the flue gas is black or dark-coloured, this is because the combustion is getting insufficient air.
The flue gas must be white or light-coloured or completely transparent.
1.8.2 This is how the uppermost and lowest doors must be opened:
●When opening the doors you ought, for the sake of safety, to stand so that the doors are between
you and the boiler opening.
●Open the door approx. 2 cm. - Wait for approx. 20 seconds. - Open the door slowly.
●If the boiler is fitted with oxygen control, the door may not be open for more than max. 1 min.
without disturbing the control's operation.
1.9 User experiences
By means of regular (daily) supervision at the beginning, you will obtain an indication of how often you
must fill up the hopper as well as removing ashes from the combustion chamber.
There must always be enough fuel in the magazine to keep it from running dry.
The risk of back-burning is increased if the magazine runs out of fuel and/or fuel other than that specified
in section 1.1.1 is used.
NB: Poorer fuel gives more problematic operation.
Wood pellets composed of pure wood residues produce comparatively little ash.
Grain is more difficult and time-demanding due to greater contents of non-combustible constituents
(salts) which form ash and often also cinders. The quantity depends, amongst other things, on the growth
conditions of the grain, its chemical composition and the extent of the fuel consumption.
If the indications in these guidelines are followed and if the surroundings of the boiler are kept more or
less clean you will, as a rule, be ensured a problem-free operation of the plant.
Page 11
1.10 Recommended adjustment of operation
The values shown below are guidelines - check flame colour and smoke colour - see section 1.8.2. If the
colour is not correct, modify the adjustment until a satisfactory colour is achieved.
Large heat requirement Small heat requirement