THERMOSTAHL ENP 20 Manual

GAS/LIQUID FUELED STEEL BOILER
ENERSAVE PLUS
INSTALLATION AND SERVICE MANUAL
VERSION:
2.4
UPDATE:
02.03.2015

Contents
1. GENERAL INFORMATION ................................................................................... 3
1.1. Proper use of the appliance ................................................................................ 3
1.2. Safety warnings ................................................................................................ 3
1.3. Data label ........................................................................................................ 3
1.4. Document information ....................................................................................... 3
2. TECHNICAL FEATURES AND DIMENSIONS ......................................................... 4
2.1. Technical features ............................................................................................. 4
2.2. Function principle .............................................................................................. 4
2.3. Working medium............................................................................................... 5
2.4. Dimensions ...................................................................................................... 6
2.5. Fuel................................................................................................................. 9
3. BOILER MOUNTING ........................................................................................... 9
3.1. Transportation and delivery ................................................................................ 9
3.2. Boiler room .................................................................................................... 10
3.2.1. General requirements ................................................................................ 10
3.2.2. Boiler room dimensions.............................................................................. 11
3.3. Chimney ........................................................................................................ 12
3.4. Mounting the burner ........................................................................................ 13
3.5. Burner mounting dimensions ............................................................................ 14
4. INSTALLATION ................................................................................................ 15
4.1. Hydraulic connections ...................................................................................... 15
4.2. Expansion vessel............................................................................................. 16
4.3. Safety features ............................................................................................... 17
4.4. Return temperature protection.......................................................................... 17
4.5. Filling the system ............................................................................................ 17
4.6. Connection diagrams ....................................................................................... 18
4.6.1. Central heating installation overview ........................................................... 18
5. ELECTRICAL CONNECTIONS ............................................................................ 19
5.1. General instructions......................................................................................... 19
5.2. Control panel functions .................................................................................... 19
5.2.1. EN-1 control panel .................................................................................... 19
5.2.2. EN-2S control panel................................................................................... 21
6. BOILER START-UP ........................................................................................... 23
6.1. Initial lighting checks ....................................................................................... 23
6.2. Start-up ......................................................................................................... 23
6.3. Checks to carry after initial start-up .................................................................. 23
6.4. Combustion regulation ..................................................................................... 24
7. SERVICE AND MAINTENANCE .......................................................................... 25
7.1. Cleaning the boiler .......................................................................................... 25
7.2. Cleaning the chimney box ................................................................................ 25
7.3. Maintenance after long stop.............................................................................. 26
7.4. Basic service procedures .................................................................................. 27
7.4.1. Service after overheating ........................................................................... 27
8. TROUBLESHOOTING ........................................................................................ 27
9. WARRANTY...................................................................................................... 28

GENERAL INFORMATION
3
1. GENERAL INFORMATION
1.1. Proper use of the appliance
Before you make use of this appliance make sure you have read and fully understood the
instructions included in this manual.
The installation and use of the appliance must be performed according to the instructions
indicated in this manual in combination with the current national safety regulations.
The appliance is designed for use in pumped hot water central heating systems. Any other use
is considered improper and is prohibited. THERMOSTAHL declines any responsibility for
damages or injuries caused by improper use; in this case the risk is completely at the user’s
responsibility.
To ensure an efficient and flawless function of the appliance, it is strongly recommended that
you have performed an annual service by a qualified technician.
1.2. Safety warnings
All installation and maintenance procedures must be carried out by professional and authorized
personnel, in compliance with the indications in the present manual and national regulations.
Any failure to correctly install this appliance could cause damage or injuries!
Do not make modifications to parts of the appliance, unless you have contacted the company
and an authorized service contractor.
Only original accessories and spare parts must be used to ensure correct and safe function.
Make sure you respect the cleaning and maintenance procedures on the corresponding
intervals. Failure to do so can cause malfunction to the appliance and possible damages.
The boiler is design to function on the fuels indicated in the corresponding paragraph. Any
other fuel is prohibited. Do not use explosive or flammable substances! Do not store such
substances inside the boiler room.
The working pressure varies according to the model. Make sure you use the appropriate water
pressure. Working in a pressure higher than the one indicated in this manual is
strictly prohibited and dangerous!
1.3. Data label
The data label of the appliance is placed on the boiler’s side cover, on the external part. Make
sure that it is properly placed and readable.
On the label it is indicated the serial number and the manufacturing year of the appliance.
1.4. Document information
This document is an integral and indispensable part of the product and must be retained in
good condition by the user. Keep it in a safe place for future reference.
If the appliance is sold or transferred to another person, this manual has to always follow the
appliance and handed to the new user or installer.

TECHNICAL FEATURES AND DIMENSIONS
4
2. TECHNICAL FEATURES AND DIMENSIONS
2.1. Technical features
The ENERSAVE boiler is made of steel, as a monobloc construction, with horizontal tubed heat
exchanger and pressurized fire chamber. It functions on the principle of reversed flame, with
three passes of burned gases: two passes in the combustion chamber and one pass in the
exhaust tubes. The heat transfer is performed through radiation at the first two passes and
through conduction at the third pass of the tubes.
It is appropriate for light oil combustion and gas combustion. It is available as an independent
boiler or as a unit with an integrated burner. It can also be combined with a hot water boiler
hot water production.
The boiler is designed for maximum working temperature of 90oC.
DESCIPTION OF COMPONENTS
Steel boiler body with horizontal tube exchanger
High efficiency stainless steel turbinators
Removable rear smoke box with inspection cleaning door
Front door insulated with refractory material, equipped with a flange for burner mounting
and a flame inspection pipe
Rockwool body insulation of 50 mm thickness
Electrostatically painted external covers
Control panel for electromechanical operation (optional)
2.2. Function principle
ENP 20 –EN 300 EN 350 –EN 2500
Fig 1. Boiler function scheme
The function of the boiler is based on the counter-pressure that is created by the returnable
flame in the combustion chamber and by the transmission of heat with radiation. The burned
gases reverse their course at the bottom of the fire chamber, surrounding this way the flame,
which does not get into immediate contact with the surrounding walls.
The burned gases are then guided towards the smoke box through the fire tubes where the
heat transfer is mainly through conductivity, and afterwards evacuated to the chimney. The
smoke box is equipped with an inspection and cleaning door, which also actions as an
explosion relief. The turbinators in the tubes create turbulence to the burned gases, so as to
get into a continuous contact with the walls of the tubes and increase the heat transfer
efficiency.

TECHNICAL FEATURES AND DIMENSIONS
5
The results a complete and perfect combustion with a small excess of air, and uniform heat
charge of the surfaces.
The door has an insulation cord to ensure air-tight closing. The door is equipped with a flange
for burner mounting and an inspection eye for flame inspection.
2.3. Working medium
The ENP boiler is designed for function with water as working medium, with a maximum
concentration in polypropylene glycose of 50%.
The maximal temperature of the water is 95ºC. The minimal temperature of the return water is
65ºC for nominal decrease of temperature ∆t=20ºC in a device of heat performance.
The boiler is appropriate for open and closed heating systems with maximal operation pressure
4 bars. The maximal operation pressure of the boilers with power bigger than 800 kW is 5
bars.
The quality of the heating plant water is an important element for the performance of the
system. The water that enters the heating plant must be clean, transparent and free from salts
and chemical substances. It must be filtered, so as no quantity of sand or mud from the water
supply comes into the boiler.
The hardness of the water must be within permissible limits. In regions where the water is
hard, it is necessary to use water softeners.
Properties of the water for use:
Appearance: clean-transparent
Total hardness: Max 20ºf
Free oxygen: Max 0,05 mg/lit
Organic substances: Max 0,5 mg/lit
PH: min 8,5

TECHNICAL FEATURES AND DIMENSIONS
6
2.4. Dimensions
ENP 20-160
Type
A
B
C
D
E
F
L
T1-T2
T3
T4
T5
T6
mm
mm
mm
mm
mm
mm
mm
inch
mm
mm
inch
inch
ENP 20
670
840
595
410
435
530
800
1 ¼”
139
106
½”
½”
ENP 30
670
840
595
510
435
530
900
1 ¼”
139
106
½”
½”
ENP 40
670
840
595
610
435
530
1000
1 ¼”
139
106
½”
½”
ENP 50
670
840
595
710
435
530
1100
1 ½”
139
106
½”
½”
ENP 60
765
970
695
635
510
635
1050
1 ½”
159
125
½”
¾”
ENP 70
765
970
695
735
510
635
1150
1 ½”
159
125
½”
¾”
ENP 80
765
970
695
835
510
635
1250
2”
159
125
½”
¾”
ENP 100
880
1045
800
940
550
635
1450
2”
193
146
½”
1”
ENP 120
880
1045
800
1040
550
635
1550
2”
193
146
½”
1”
ENP 140
880
1045
800
1140
550
635
1650
2 ½”
193
146
½”
1 ¼”
ENP 160
880
1045
800
1290
550
635
1800
2 ½”
193
146
½”
1 ¼”

TECHNICAL FEATURES AND DIMENSIONS
7
ENP 180-2500
Type
A
B
C
D
E
F
L
T1-T2
T3
T4
T5
mm
mm
mm
mm
mm
mm
mm
inch
mm
mm
inch
ENP 180
1040
1240
970
1050
585
780
1600
2 ½”
244
160
1”
ENP 200
1040
1240
970
1050
585
780
1600
2 ½”
244
160
1”
ENP 220
1040
1240
970
1300
585
780
1800
2 ½”
244
160
1”
ENP 250
1040
1240
970
1300
585
780
1800
2 ½”
244
160
1”
ENP 300
1040
1240
970
1550
585
780
2050
3”
293
160
1”
ENP 350
1290
1545
1185
1320
750
1020
2150
DN 80
343
220
1”
ENP 400
1290
1545
1185
1320
750
1020
2150
DN 80
343
220
1”
ENP 450
1290
1545
1185
1570
750
1020
2400
DN 100
343
220
1”
ENP 500
1290
1545
1185
1570
750
1020
2400
DN 100
343
220
1”
ENP 550
1290
1545
1185
1820
750
1020
2650
DN 100
343
220
1”
ENP 600
1290
1545
1185
1820
750
1020
2650
DN 100
343
220
1”
ENP 650
1290
1545
1185
2070
750
1020
2900
DN 125
343
220
1”
ENP 700
1540
1935
1445
1580
920
1080
2450
DN 125
343
270
1”
ENP 750
1540
1935
1445
1580
920
1080
2450
DN 125
343
270
1”
ENP 800
1540
1935
1445
1830
920
1080
2700
DN 125
395
270
1”
ENP 900
1540
1935
1445
2080
920
1080
2950
DN 125
395
270
1”
ENP 1000
1540
1935
1445
2080
920
1080
2950
DN 125
395
270
1”
ENP 1100
1540
1935
1445
2330
920
1080
3200
DN 150
395
270
1”
ENP 1200
1540
1935
1445
2330
920
1080
3200
DN 150
395
270
1”
ENP 1300
1540
1935
1445
2330
920
1080
3200
DN 150
485
270
1”
ENP 1400
1540
1935
1445
2580
920
1080
3450
DN 150
485
270
1”
ENP 1500
1540
1935
1445
2580
920
1080
3450
DN 150
485
270
1”
ENP 1650
1540
1935
1445
2830
920
1080
3700
DN 150
485
270
1”
ENP 1800
1940
2235
1850
2100
1250
1500
3200
DN 150
580
380
1 ¼”
ENP 2000
1940
2235
1850
2100
1250
1500
3200
DN 150
580
380
1 ¼”
ENP 2300
1940
2235
1850
2600
1250
1500
3700
DN 200
580
380
1 ¼”
ENP 2500
1940
2235
1850
2600
1250
1500
3700
DN 200
580
380
1 ¼”

TECHNICAL FEATURES AND DIMENSIONS
8
TECHNICAL DATA
Type
Nominal
power
Back-
pressure
Fire
chamber
volume
Heated
surface
Pressure
drop
Water
content
Weight
Pmax
Effici
ency
Mcal/h
kW
mm H2O
lit
m2
(Δt=15oC)
mmH2O
lit
kg
bar
%
ENP 20
20
23
2..4
24
1,2
20
46
158
4
91,5
ENP 30
30
35
2..4
31
1,6
20
57
179
4
91,5
ENP 40
40
47
2..4
39
1,9
20
70
197
4
91,5
ENP 50
50
58
2..4
47
2,4
30
81
220
4
91,5
ENP 60
60
69
4..6
56
2,6
40
117
271
4
91,5
ENP 70
70
81
4..6
64
3,1
50
128
308
4
91,5
ENP 80
80
93
6..10
76
4,5
75
138
416
4
91,5
ENP 100
100
116
6..10
144
4,9
80
246
439
4
91,5
ENP 120
120
140
6..10
161
6,0
90
282
465
4
91,5
ENP 140
140
163
8..15
179
6,7
100
305
502
4
91,5
ENP 160
160
186
10..20
205
7,2
120
326
538
4
91,5
ENP 180
180
209
10..20
206
6,7
100
400
687
4
93
ENP 200
200
233
10..20
206
7,2
120
427
747
4
93
ENP 220
220
256
10..20
263
8,0
150
471
782
4
93
ENP 250
250
291
10..20
263
8,7
150
523
805
4
93
ENP 300
300
349
20..30
320
10,3
180
607
885
4
93
ENP 350
350
407
20..30
423
13,4
200
782
1518
4
93
ENP 400
400
465
20..30
423
13,4
200
753
1529
4
93
ENP 450
450
522
20..30
539
15,8
220
809
1587
4
93
ENP 500
500
581
20..30
539
15,8
220
809
1598
4
93
ENP 550
550
637
20..30
577
16,8
250
848
1621
4
93
ENP 600
600
698
20..30
577
18,3
250
877
1690
4
93
ENP 650
650
756
30..40
692
20,7
300
947
1817
4
93
ENP 700
700
814
30..40
872
23,3
350
1180
2250
5
93
ENP 750
750
872
30..40
872
24,0
350
1250
2390
5
93
ENP 800
800
930
30..40
1052
25,4
22.73333
3333
350
1325
2510
5
93
ENP 900
900
1047
30..40
1052
26,3
400
1365
2620
5
93
ENP 1000
1000
1163
30..40
1098
27,1
400
1390
2710
5
93
ENP 1100
1100
1279
30..40
1280
29,8
400
1440
2880
5
93
ENP 1200
1200
1396
30..40
1280
31,0
400
1495
2980
5
93
ENP 1300
1300
1453
30..40
1280
33,2
400
1550
3090
5
93
ENP 1400
1400
1628
30..40
1390
34,5
400
1640
3220
5
93
ENP 1500
1500
1740
30..40
1390
36,8
400
1740
3360
5
93
ENP 1650
1650
1919
30..40
1550
39,0
400
1830
3650
5
93
ENP 1800
1800
2093
40..60
1940
39,7
450
2178
4455
5
93
ENP 2000
2000
2326
40..60
1940
40,5
450
2140
4570
5
93
ENP 2300
2300
2675
40..60
2185
47,1
450
2464
5220
5
93
ENP 2500
2500
2887
40..60
2785
54,5
450
2600
5800
4
93
ENP 2500
2500
2887
40..60
2785
54,5
450
2600
5800
5
93

BOILER MOUNTING
9
2.5. Fuel
The ENP is designed for function with the following fuels:
1. Natural Gas, according to DIN 4756 and 4788, with lower calorific power 8.500 kcal/Nm3.
The delivery conditions of natural gas to the burner are stabilized by the Norm for natural
gas I 6-98, for gas with low pressure (p=500 mmCA)
2. Light oil fuel EL, according to DIN 4755 and 4787, with a viscosity of 4, 5 cSt at 20oC and
lower calorific power 9.900 kcal/kg.
3. Light oil fuel with lower calorific power 9.650 kcal/kg.
No other fuel than the ones mentioned should be used with this boiler! If you
wish to use an alternative fuel, please contact the manufacturer.
When liquid fuel is used, pay attention at the following:
When filling the fuel tank, avoid any water or dust entering together with the fuel in the tank.
When the room temperature of the location where the boiler is mounted is lower than 0oC, it is
recommended the use of a pre-heater.
3. BOILER MOUNTING
3.1. Transportation and delivery
The boiler is delivered complete with the metal covers, well packaged. The loading and
unloading of the boiler must be performed with a forklift or a crane. A special hook is provided
on the upper part of the boiler for lifting.
The boiler is heavy. Do not try to lift by hands or other unsuitable equipment.
Danger of injury! Perform all moves with extreme attention and care.
Remove the boiler packaging with attention. Keep the packaging material away from
children since it can be dangerous. After having unpacked everything, make sure that the
appliance is intact and undamaged. In case of doubt do not use the appliance and inform the
supplier.
The ENP boiler is delivered with the following equipment already fitted and mounted:
Boiler steel body
Rockwool insulation mounted on the boiler body and tightened with plastic tapes
Metal covers mounted on the boiler body
Turbinators positioned inside the fire tubes
The following accessories are positioned inside the boiler body. Remove them carefully by
opening the middle door.
Cleaning tools
Drainage valve
Burner sealing cord
Control panel (optional)
In the documentation folder you will find:
Technical manual
Warranty leaflet
Declaration of conformity

BOILER MOUNTING
10
3.2. Boiler room
3.2.1. General requirements
The boiler must be installed in a special and separate room. This room must be chosen so that
it offers easy access for fuel transport, air supply and exhaust gas evacuation. The doors of the
boiler room must be metallic, open outwards, and have at least 0,9 m width.
The boiler installation is prohibited in rooms with extensive dust, dangerous
gases, and moist spaces.
For the correct boiler function it is necessary that the boiler room has openings for natural
ventilation and combustion air supply. It is recommended that two different openings are used
for this purpose, positioned on opposite walls and diagonally to ensure good air circulation. The
cross section of the openings can be estimated by the following formula:
F=Q*8 /1000
Where F=Surface of the opening in cm² (with grid)
(Without grid by receiving 2/3 of the F)
Q=Heating power of the boiler in kcal/h
The boiler room must be provided with a drainage channel. All safety devices must be
connected to this channel.
The boiler room must have an appropriate fire extinguishing system, according to the
regulations in force. In case that the building is designed with a fire alarm system, a smoke
detector must be positioned on top of every boiler.
The fuel storage is prohibited in the boiler room. If so, the storage must be separated from the
boiler with a non-flammable wall, and proper distanced from the boiler.
Fig 2. Boiler room ventilation and air supply

BOILER MOUNTING
11
3.2.2. Boiler room dimensions
The boiler must be placed on a horizontal plane, with adequate mechanical resistance to
support the boiler’s weight. The boiler must be positioned in the room in such a way so that it
is easily accessible from all the sides. The following dimensions are recommended (see Fig 3):
Distance from the front wall (N):
For boilers up to 100 kW –minimum 1,5 m
For boilers bigger than 100 kW –minimum 2 m
Distance from the rear wall (L):
Appropriate distance for maintenance access. Minimum 0,6 m.
Distance from side walls (M):
For boiler up to 300 KW –minimum 0,6 m
For boilers bigger than 300 kW –minimum 1 m
Boiler room height (H):
For boilers up to 70 kW –minimum 2 m
For boilers 70 to 230 kW –minimum 2,4 m
For boiler 230 to 400 kW –minimum 3 m
For boiler bigger than 400 kW –minimum 3,5 m
Distance between two boilers (P) must be at least 1m.
Fig 3. Recommended boiler room dimensions

BOILER MOUNTING
12
3.3. Chimney
The chimney installation must supply sufficient draught, air tightness and protection against
condensation.
The appropriate chimney installation is very important for the boiler’s efficient
and safe function!
The chimney must be positioned if possible in the interior of the building. It must be vertical,
with no changes in the direction. The cross-section of the chimney can be round or
rectangular. If the chimney is installed in the exterior, it must be insulated.
The horizontal part connecting the boiler’s chimney pipe with the vertical chimney must have
maximum length 2 m. If this distance is bigger, it is recommended to have a 15-30oinclination
upwards. The connection with the boiler’s chimney pipe must be air-tight.
The chimney must be equipped with a cleaning door at its base. Also cleaning doors are
recommended where there are changes in direction and ash can be accumulated. Tactical
cleaning is recommended (every 3 months) for efficient boiler function.
A chimney terminal must be installed at the end of the chimney for protection against weather
effects and foreign objects entrance. In areas with strong winds a special anti-downdraught
terminal is recommended.
The chimney height must exceed the roofline by at least 1 m. If there are other obstacles
positioned on the roof, the chimney height must exceed them by at least 1 m. If there are
multiple chimneys, minimum distance between them is 0,3m.
Each boiler should be connected to an independent chimney. Connection of multiple boilers to
the same chimney is not recommended.
Fig 4. Chimney distances
Fig 5. Chimney connection

BOILER MOUNTING
13
3.4. Mounting the burner
The ENP boilers are overpressure boilers and it is necessary to take into account the static
pressure of counter-pressure in the combustion chamber to select the proper burner. The
dimensions of the flange on the boiler door for mounting the burner as well as of the support
screws are according to DIN 4789. The part of the fuel pipes, which are connected to the
burner must have sufficient length and must be flexible, in order to allow the opening of the
boiler door.
The gap around the boiler flange is filled by fireproof ceramic material. The supply of fuel must
be adjusted at the nominal power of the boiler, by selection of the appropriate atomizer.
For the mounting of the burner on the boiler, you must take care of the following:
The burner must be well fixed on the special flange of the boiler. The four screws must be
fastened well, so that the burner is not loose on the boiler.
The sealing flange of the burner ensures insulation from combustion gas leaks. Take care
that it does not break.
The injection neck of the burner must be deep enough in the boiler, so that its edge reaches
deeper than the plate that carries the tubes. The burners with long injection neck are more
proper for boilers made of steel.
The burner must be positioned horizontally and parallel to the combustion chamber.
The position of the burner must be correctly aligned in connection with the center of the
combustion chamber. In this way a uniform flame is developed and a better distribution of
the thermal load is ensured.
The door must fit well on the sealing cord in order not to have combustion gas leaks.
The space between the injection neck of the burner and the door of the boiler must be
insulated with fireproof material.
The fireproof material of the door of the boiler must be replaced with new material, if it gets
damaged during the use.
The burner neck must penetrate inside
the combustion chamber in a way that the
entire heat exchange surface of the fire
chamber is performed uniformly by the
exhaust gas. If the neck of the burner is of
very small size, the flame goes directly to
the fire tubes, a fact that results in excessive
increase of the thermal strain of the boiler.
Legend
1.
Burner
2.
Burner mounting flange
3.
Door insulation with fire proof material
4.
Insulation around the injection neck of the
burner
5.
Boiler door
6.
Ceramic insulation flange
7.
Sealing cord
8.
Burner injection neck
9.
Tube
10.
Boiler front plate

BOILER MOUNTING
14
3.5. Burner mounting dimensions
Boiler
type
Power
(kW)
Bentone burner
F.B.R. burner
Dimensions
D(Фmm)
L1(mm)
L2(mm)
ENP 15
18
BFG1 H2
GAS X0 TL
114
126
20
ENP 20
23
BFG1 H2
GAS X0 TL
114
126
20
ENP 30
35
BFG1 H2, BFG1-2 H3
GAS X1 TL; GAS X1-2 TL
114
126
20
ENP 40
47
BFG1 H2, BFG1-2 H3
GAS X1 TL; GAS X1-2 TL
114
126
20
ENP 50
58
BFG1 H3, BFG1-2 H3
GAS X2 TL; GAS X2-2 TL
139
118
20
ENP 60
69
BFG1 H3, BFG1-2 H3
GAS X2 TL; GAS X2-2 TL
139
118
20
ENP 70
81
BFG1 H3, STG146-2L
GAS X2 TL; GAS X2-2 TL
139
118
20
ENP 80
93
BG300-L, STG146-2L
GAS X3 TL; GAS X3-2 TL
159
125
20
ENP 100
116
BG300-L, BG300-2L
GAS X3 TL; GAS X3-2 TL
159
125
20
ENP 120
139
BG300-L, BG300-2L
GAS X4 TL; GAS X4-2 TL
159
125
20
ENP 140
163
BG400-L, BG400-2L
GAS X5 TL; GAS X5-2 TL
193
155
25
ENP 160
186
BG400-L, BG400-2L
GAS X5 TL; GAS X5-2 TL
193
155
25
ENP 180
209
BG400-L, BG400-2L
GAS X5 TL; GAS X5-2 TL
193
155
25
ENP 200
232
BG400-2L, BG400-ML
GAS X5 TL; GAS X5-2 TL
193
155
25
ENP 250
291
BG450-2L, BG450-ML
GAS XP60 TL; GAS XP60-2 TL
273
226
25
ENP 300
349
BG450-2L, BG450-ML
GAS XP60 TL; GAS XP60-2 TL
273
226
25
ENP 350
407
BG550-2L, BG550-ML
GAS XP60 TL; GAS XP60-2 TL
273
226
25
ENP 400
465
BG550-2L, BG550-ML
GAS XP60 TL; GAS XP60-2 TL
273
226
25
ENP 450
522
BG650-2L, BG650-ML
GAS P70-2 TL
356
286
25
ENP 500
581
BG650-2L, BG650-ML
GAS P70-2 TL
356
286
25
ENP 600
698
BG650-2L, BG650-ML
GAS P100-2 TL
356
286
25
ENP 700
814
BG650-2L, BG650-ML
GAS P100-2 TL
356
286
25
ENP 800
930
BG700-2L, BG700-ML
GAS P100-2 TL
425
328
30
Manufacturer approves only the burners specified in this manual. If you want
to use other burners contact the manufacturer, otherwise you risk losing your
warranty.

INSTALLATION
15
4. INSTALLATION
4.1. Hydraulic connections
ENP 20-160
ENP 180-2500
The boiler is intended for connection with a closed expansion vessel network. The boiler is
intended for maximum working temperature 90oC and maximum pressure 3 bars.
The expansion vessel must be connected on the return line. The discharge valve must be
connected through a pipe to the drainage.
If a connection pipe is not used, it must be sealed before water fill!
Legend
T1
Boiler outlet
T2
Boiler inlet
T3
Chimney connection
T5
Drainage valve
T6
Safety connection
Legend
T1
Boiler outlet
T2
Boiler inlet
T3
Chimney connection
T5
Drainage valve

INSTALLATION
16
Legend
1.
Burner
2.
Control panel
3.
Manometer
4.
Safety kit
5,7,8.
Safety valve
6.
Air relief valve
9.
Drainage valve
10.
Ball valve
11,13,15.
Pump
12.
One-way valve
14.
Expansion vessel
4.2. Expansion vessel
The ENP boiler is recommended to be connected with closed expansion vessel. The volume of
the expansion vessel is calculated according to the quantity of the water in the installation and
the static height. When choosing the expansion vessel, it should never be chosen marginal
size, but a size greater.
The expansion vessel should be connected at the return line of the boiler. Before the
installation, the pressure inside the expansion vessel should be regulated according to its
geometrical height from the point of its position up to the highest point of the installation. If
this height is lower than 8 m, then the pressure is adjusted at 0,8 bar. If the boiler room is on
a rooftop, the pressure on the tank should be adjusted at 0,5 bar.
The automatic filling valve must be installed next to the expansion tank and it is adjusted so
that, when the installation is cool, there is a pressure equal to the geometrical height
mentioned above plus 2 m. In areas where high-pressure distributing networks are present, a
pressure reducing gear must be placed.

INSTALLATION
17
4.3. Safety features
The boiler equipment includes a safety kit, which shall be connected to the corresponding
safety connection pipe. The kit consists of a safety valve, an air relief valve and a
thermomanometer.
Additional safety equipment can be mounted on the outlet line, at a distance less than 1,5 m
from the boiler.
Fig 6. Boiler safety kit
4.4. Return temperature protection
For the correct function of the boiler and for protection against condensation and corrosion it is
very important to ensure steady temperature at the return of the boiler of at least 55oC.
This can be ensured by installing a recirculation pump between the boiler outlet and return
(see connection diagrams). An alternative variation is by installing at the return of the boiler a
three-way thermostatic valve.
4.5. Filling the system
After completing all the hydraulic connections, the circuit may be filled with water. After filling
the system, open the radiators air valves to get rid of the air in the installation.
Verify that the installation pressure is according to the technical feature of the boiler. The
pressure must be verified through the boiler’s manometer. An additional manometer should be
installed on the cold water inlet to verify the cold pressure, at the lowest point of the
installation, at a point close to the boiler.
The whole installation must remain under nominal pressure for at least 10 minutes. During this
period, check that all the connections are tight and there are no water leakages. Make sure
that during this period no pressure drop appears.
After firing the boiler, make sure the network functions properly at working temperature and
pressure.
The hardness of the mains water supply affects the boiler’s life span. It is
recommended to use a water softener if water hardness exceeds 15of.
Do not fill the system at the working pressure! When the boiler will be heated,
the water pressure will raise. Filling pressure must be at least 1 bar lower
than working pressure!
Type
Safety kit*
EN 15-50
½”
EN 60-80
¾”
EN 100-120
1”
EN 140-160
1¼”
*Safety kit is not included. Contact the
manufacturer for further information.

INSTALLATION
18
4.6. Connection diagrams
4.6.1. Central heating installation overview
Legend
1.
Boiler
15.
Water filter
2.
Burner
16.
Radiators
3.
Burner filter
17.
Radiators valves
4.
Pump
18.
Expansion vessel
5.
Fuel tank
19.
Automatic water filler
6.
Water-level indicator
20.
Burner thermostat
7.
Tank ventilator
21.
Pump thermostat
8.
Tank alimentation
22.
4-way mixing valve
9.
Tank plug
23.
Control panel
10.
Fuel valve for the burner
24.
External temperature sensor
11.
Electromagnetic oil valve
25.
Chimney
12.
Water return
26.
Chimney cleaning door
13.
Outlet water collector
27.
Drainage
14.
Return water collector

ELECTRICAL CONNECTIONS
19
5. ELECTRICAL CONNECTIONS
5.1. General instructions
All electrical connection must be performed by an authorized professional, in conformity with
the local regulations and the indications of this manual. Connections must be done according
to norms EN 60529 and EN 60335-1, and protection norms IP 40 and IP 44.
All wiring must be waterproof insulated. Exposed cables should be protected within plastic
channel. The main electrical supply of the boiler must be connected to an independent safety
of max 16A. The boiler room lighting must be on a separate circuit.
The user is obliged to connect the boiler to an efficient grounding system.
THERMOSTAHL ROMANIA SRL declines any liability for damage caused to
people, animals and goods, due to defects caused by faulty electrical
connections or lack of connecting the boiler to an efficient grounding system.
5.2. Control panel functions
5.2.1. EN-1 control panel
Fig 7. EN-1 control panel
The general switch ON/OFF interrupts the electrical supply to all the devices.
The burner thermostat interrupts the burner function when the preset boiler temperature has
been reached. It is recommended that this temperature is set between 70-90oC. This
temperature should never be set below 55oC. Please note that various pellet burners might
have different electrical connections. In any case follow the manufacturer’s instructions.
The pump thermostat starts the circulation pump function at the preset temperature. It is
recommended that this temperature is set around 45-55oC.
The safety thermostat will interrupt electrical supply if the boiler temperature reaches above
95oC. If so, it needs to be reset manually by unscrewing the plastic cover.
The burner and pump indication lamps follow the function of the corresponding devices.
The control panel offers the possibility to connect with a room thermostat. When the room
thermostat contact opens, the burner function stops.
Legend:
1.
Thermometer
2.
Burner thermostat
3.
Safety thermostat
4.
General ON/OFF switch
5.
Burner indication lamp
6.
Pump indication lamp
7.
Pump thermostat

ELECTRICAL CONNECTIONS
20
Fig 8. EN-1 control panel wiring diagram
Legend:
M
General ON/OFF switch
TS
Safety thermostat
TB
Burner thermostat
TP
Pump thermostat
L
General function lamp
LB
Burner indication lamp
LP
Pump indication lamp
TR
Room thermostat
PE
Grounding
Unscrew the control panel back plate to have access to the connection terminals in the interior.
Connect the main electrical supply to the terminals 1, 2, 3 as indicated. The burner is
connected to the terminals 9, 10, 11 and the pump to the terminals 4, 5, 6.
Between the terminals 7, 8 there is a jumper. If you want to connect a room thermostat,
remove the jumper and connect it to these two terminals.
Attention: The room thermostat must be a simple contact interrupter. It is not
allowed to connect a digital thermostat with an electrical signal output!