STIEBEL ELTRON IS E User manual

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Service Manual
IS_E / IS_E-2
Author: Mr. Apiwat Limrueangwattanakul
Date: 25 March 2013
Revision: version 1.0

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Table of Contents
Warning.......................................................................................................................................................... 3
General product information......................................................................................................................... 4
Technical data ................................................................................................................................................ 5
Wiring Diagram .............................................................................................................................................. 6
Troubleshooting............................................................................................................................................. 7
Root clause analysis ....................................................................................................................................... 9
1. Heating Elements checking................................................................................................................ 9
2. TRIAC checking ............................................................................................................................... 10
3. Flow Switch checking ...................................................................................................................... 11
4. PCB Control checking ....................................................................................................................... 13
5. Thermostat checking ...................................................................................................................... 13
6. System comfirm ............................................................................................................................... 15

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Warning
Warning: This service manual is suitable for qualified Technicians only.
Warning: Disconnect power supply before open cover.

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General product information
The Stiebel Eltron IS pressureless (open) instantaneous water heater is a device for
heating water for shower. The electrical power is electronically controlled. The unit switches the
power on once the flow volume reach 1.5-2 l/min.
The “Power” light (C) indicates that the unit is switched on. If the temperature
adjustment rotary (B) switch is turned to the left, it is possible to take a cold shower (the heating
will not be switched on).
The IS is fitted with an overheating protection device. In the event of overheating the
heating power will be cut off.

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Technical Data
Model
IS 35E/E-2
IS 45E/E-2
IS 60E/E-2
Type
Opened outlet
Water pressure
0 Mpa (0 bar)
Water connection
G 1/2" (external thread)
Electrical connection

220 V
kW
3.5
4.5
6.0
230 V
kW
3.8
4.9
6.6
240 V
kW
4.2
5.4
7.1
Recommended cable size Sqmm.
4.0
6.0
6.0
Recommended circuit breaker A
20
30
35
Min flow rate to active unit (L/min)
1.3 ± 0.3
2.2 ± 0.3
Thermostat (TCO)
DOUBLE ACTION (55 °C / 75 °C)
Dimension (W x H x D) mm.
350 x 210 x 100

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Wiring Diagram
Type IS...E / IS…E-2
A = Heating element
B = Electronic control set
C = ELSD Circuit
D= Single Triac Set
E = Thermal cut - out (TCO)
F = Button Board
G = Current Leakage Sensor
Type IS…
A = Heating element
B = Electronic control set
D = Single Triac Set
E = Thermal cut - out (TCO)
A
E
F
D
G

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Troubles shooting
- ELSD cut-off
- Check filter, and flow
rate
-Low flow
- No power supply to unit
- Power line not tight
- Check breaker
- Thermal cut-out (TCO)
- Check Triac set
- Check Reed switch
- Cleaning magnet
- Check PCB
- ELSD reset
- Check connecting
points and fix.
Power lamp not "ON"
and water not hot
- PCB failure
- Check PCB
- Missing water connection
- Check reed switch
- Reed switch failure
- Check Triac set
- Triac failure
Problem & Condition
Cause
Correction
- Reconnect inlet,
outlet
Power lamp "ON"
but water not hot
- Heating elements failure
- Check Heating
element
Power lamp not "ON"
but water Hot
- Lamp broken
- Lamp cable broken
- Check & change the Lamp
- Check & change Lamp
cable
Power lamp "ON" all the
time
- Reed switch failure
- Check reed switch
- Triac short circuit
- Check Triac set

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Problem & Condition
Cause
Correction
- Overloaded current on main
breaker
- Power line wrong connection
- Turn off other appliance
- Reconnect power
line
- Water over flow
- Reduce water flow
ELSD cut-off
- Reed switch failure
Water temperature
not constant
- Change pump to
smooth pressure type
- Check reed switch
- Irregular water flow
- Triac failure
- Check Triac set
Water leak
- Wrong installation
v
- Reinstallation
- Connector has loosen
- Tight connectors
- PCB failure
- Check PCB
Power on maximum but
water not hot enough
Water too hot
Troubles shooting

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Root clause analysis
1. Heating Elements checking
Definition: Heating Element is a metal coil that heats up to high temperatures, when
electricity is applied. To check the Heating Element, follow the steps below:
- Disconnect cables from the Elements.
- )))) "and check as show in the pictures.
Check
Meter Result
Cause
Action
Pole Pole
"Beep" signal or (~ 0 )
Element Pass
No action
No signal "OL" or 
Element Broken
Change New Heater
Pole GRD
"Beep" signal or (~ 0 )
Element short to tank
Change New Heater
No signal "OL" or (∞
Element Pass
No action
Remark: "OL" = Over Load for Digital Multimeter, "∞Multimeter
Pole Tank (P1 - Tank) or (P2 - Tank), (GRD - Tank)
Pole - Pole (P1 - P2), (P1 - GRD) or (P2 - GRD)
IS 60E/E-2
P1
P2
IS 35E/E-2, 45E/E-2
Or
P2
P1
GRD
P2
GRD
P1
Or
Tank
P2
Tank
P1
IS 3E/E-2, 45E/E-2
IS 60E/E-2
GRD
Tank
P1
Tank
Or

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2. TRIAC Checking
Definition: The Triac is a three-terminal device, which controls and conducts current flow during
both alternations of an AC cycle. To check Single Triac, follow the steps below:
- Disconnect cables and unplug any connectors in red circle.
- )))) " and check as show in the pictures.
Note; L1 = line, H1 = Heater, GRD = Ground
Check
Meter Result
Cause
Action
L1 H1
"Beep" signal or (~ 0 )
Triac short circuit
Change new
No signal "OL" or (∞
Triac Pass
No action
Check
Meter Result
Cause
Action
L1 - GRD
"Beep" signal or (~ 0 )
Triac short circuit
Change New Triac PCB
No signal "OL" or (∞
Triac Pass
No action
H1- GRD
"Beep" signal or (~ 0 )
Triac short circuit
Change New Triac PCB
No signal "OL" or (∞
Triac Pass
No action
Remark: "OL" = Over Load for Digital multimeter, "∞ultimeter.
GRD
H1
Poles - Ground
L1
GRD
GRD
L1
H1

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3. Flow switch checking
Definition: Flow switch (Reed sw.) is a vacuum tube with two thin metallic strips at open circuit
(NO) configuration while on standby. It activates or goes on close circuit by use of a magnet.
Below you will find two different ways to check the flow switch.
3.1) Option 1: Set unit at vertical direction
-)))) " and unplug the reed switch connector from the
printed circuit board (PCB) and check Reed Switch as in the pictures.
Check
Meter Result
Cause
Action
Pole -Pole
"Beep" signal " )))) "
Reed SW contact closed
Change new one*
No signal "OL" or (
Pass
No action
* Recommend replacing magnet set at the same time.
UP
Pole - Pole

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3.2) Option 2: Set unit to upside down (turn 180 ˚) direction.
-          )))) " and unplug the reed switch connector from the
printed circuit board (PCB) and check Reed Switch as in the pictures.
Check
Result
Cause
Action
Pole -Pole
"Beep" signal " )))) "
Pass
No action
No signal "OL" or (
Reed switch contact closed
Change new one*
* Recommend replacing magnet set at the same.
Down
Pole - Pole

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4. PCB control checking
Check
Result
Cause
Action
Visual
Electronic equipment is burned
Short circuit
Change new PCB
Damage is not visible
PCB failed
Change new PCB
Visual check

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5. Thermostat checking
Automatic Reset Thermostat
Definition: The thermostat will automatically cut out power system when the water in tank rises
to 4the thermostat, follow the steps below:
-Disconnect cables as in the picture.
- Set multimeter to Ohm r))))
- Check on poles.
Check
Result
Cause
Action
Pole -Pole
"Beep" signal " )))) "
Pass
No action
No signal "OL" or (
Connector open
Automatic reset*
Remark: "OL" = Over Load for Digital multimeter, "∞ultimeter.
*Note: Please ensure that step 1-
IS 45E/E-2 , IS 60E/E-2
IS 35E/E-2

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6. System confirm
Ensure that you have tightened all the screws back into their original positions. This final test must
be performed after repairing the unit. If all steps below are working correctly the unit can be
returned to the end user.
1. If available, set the unit in test station and turn the knob to the OFF position.
2. Connect electricity wiring to the unit and connect the water valve, then supply water to
the system to check for leaks but keep the main breaker to the unit turned off.
3. If no water leaks where discovered turn the breaker on and push the reset button
upwards to reset the ELCB.
4. Try to adjust knob (temperature). If the water is warm, the unit is ready to use.
5. Purge water inside tank and the unit is cleaned with compressed air.
Visual check