STIEBEL ELTRON AQ 35 E-2 User manual

1
Service Manual
AQ 35,45 E-2
Author: Mr. Apiwat Limrueangwattanakul
Revision: version 1.0

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Table of Contents
Warning ......................................................................................................................................................... 3
General product information......................................................................................................................... 4
Technical Data................................................................................................................................................ 5
Wiring Diagram .............................................................................................................................................. 6
Troubles shooting .......................................................................................................................................... 7
Root Cause Analysis ....................................................................................................................................... 8
1. Heating Elements Checking ............................................................................................................... 8
2. TRIAC Checking .................................................................................................................................. 9
3. Flow Switch Checking....................................................................................................................... 10
3.1) Set unit at vertical direction ......................................................................................................... 10
............................................................................. 11
3.3) The other way to activate Flow Switch......................................................................................... 12
4. PCB Control Checking....................................................................................................................... 13
5. Thermostat Resetting ...................................................................................................................... 14
6. System Confirm................................................................................................................................ 15
7. AQ (E) Parts List................................................................................................................................ 16
7.1 Spare Parts list, Model: AQ 35E ..................................................................................................... 17
7.2 Spare Parts list, Model: AQ 45E ..................................................................................................... 18
7.3 Spare Parts list, Model: AQ 60E ..................................................................................................... 19

3
Warning
Warning: This service manual is suitable for qualified Technicians only.
Warning: Disconnect power supply before open cover.

4
General product information
The AQUAPOWER pressure less (opened outlet) small instantaneous water heater that is
device to heating water for shower. The electrical power is electronically controlled. The flow is
switched on and off by using a water valve.
The unit switches the power on once the flow volume is sufficient. The "Power" light indicates
that the unit is switched on. Any desired temperature can be set by turn right of rotary switch,
The AQ_E-2 model 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
AQ 35E-2
AQ 45E-2
Type
Opened outlet
Outlet Pressure
0 Mpa (0 bar)
Water Connector
G 1/2"
Power Supply

- Rated Power @ 220 V (kW/A)
3.5-15.29
4.5-20.5
- Rated Power @ 230 V (kW)
3.8-16.5
4.9-21.3
- Rated Power @ 240 V (kW)
4.2-17.5
5.4-22.5
Cable Size (Sq.mm)
2.5-4.0
2.5-4
Circuit Breaker (A)
20
25
Dimension H x W x D (mm)
200 x 360 x 110
Unit weight (kg)
1.2

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

7
Troubles shooting
Problem & Condition
Cause
Correction
Power lamp not "ON"
And water not hot
- No power supply to unit
- Low flow
- Power line not tight
- Check breaker
- Check connect points and fix
it.
- Check filter, and flow rate
- Reconnect inlet, outlet
- Check Reed switch set
- Check Thermostat
- Missing water connection
- Reed switch failure
- Triac failure
- Thermal cut-out (TCO)
- Check Triac set
- Heating element broken
- Check heating elements
Power lamp "ON"
But water not hot
Water leak
- Tight connectors
- Connector has loosen
- Wrong installation
- Reinstallation
- Lamp broken
- Lamp cable broken
- Check & change the Lamp
- Check & change Lamp cable
Power lamp not "ON"
But water Hot
Water too hot
- Check Reed switch set
- Reed switch failure
- Triac failure
- Check Triac set
- Heating elements failure
- Check heating elements
- Check Reed switch
- Reed switch failure
Power on maximum but
water not hot enough
- Irregular water flow
- Change pump to smooth
pressure type
Water temperature
not constant
- Overloaded current
on main breaker
- Turn off other appliances
- Change main breaker
Breaker cut-off
- Power line wrong connection
- Reconnect power line L, N, G

8
Root Cause 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.
- Set Multi )))) "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 - Pole (P1 - P2)
P1
P2
Pole - GRD (P1 - GRD) or (P2 - GRD)
Or
GRD
P1
P2
GRD

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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.
- Set Mu)))) " 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, "r
GRD
L1
H1
GRD
H1
L1
GRD
Poles - Ground

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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.
3.1) Set unit at vertical direction
Simulate like a unit standby Flow Switch (Reed SW.) still open circuit (as no water supply).
- Set Multi )))) " and unplug the reed switch connector from the
Control PCB and check Reed Switch as in the pictures.
Check
Meter Result
Cause
Action
Pole - Pole
"Beep" signal or (~ 0 )
Reed SW. contact closed
Change new one*
No signal "OL" or (
Pass
No action
Remark: "OL" = Over Load for Digital Multimeter, "
* Note: Recommend replacing magnet set at the same time.
Pole - Pole