STIEBEL ELTRON CF 12 KW - Cold Element Resistivity by Heater Type (in Ohms); Fault Table; Solutions Based on Symptoms in Fault Table; 4 Troubleshooting

WWW.STIEBEL-ELTRON-USA.COM CF SERIES | 5
4. Troubleshooting
Before troubleshooting, check the following items:
f Is the water pressure more than 3 psi (0.21 bar)?
f Is the electric supply a:
- Wye (4 wires + ground) or
- Delta (3 wires + ground)?
f Does the electric supply match the voltage and configuration
designation shown on the unit nameplate?
f If the heater fails to maintain the desired temperature, check
the flow rate according to the table See 10.3, “Maximum tem-
perature rise”, pg. 24.
The following items are required for testing to diagnose a possible
failure:
Continuity tester, 600 V voltage meter, amp and Ohm meter.
Use the following steps for diagnosis:
f Turn off the power supply to the heater.
Caution: follow all safety precautions in 2.2, “Safety precau-
tions”, pg. 3.
f Turn off the heater on/off switch (6).
f Open the heater enclosure.
f Check for any loose connections, and properly operating
breakers.
f Turn the delay switch timer (4) knob all the way to the left.
f Purge the heater to allow it to cool down and reset the
thermostat.
f Turn the main breaker back on. Turn on the heater on/off
switch (6). For a resistivity test, turn the breaker off and check
voltage just in case.
4.1 Fault table
Symptom Possible cause Action
No hot water (A)
(B)
(C)
(D)
(E)
(F)
(G)
(H)
(I)
Circuit breakers off Turn circuit breakers on
On/off switch (6) defect Check voltage
Delay timer (4) defect Check voltage
Pressure switch (3) Check voltage
Contactor (5) Check voltage A
1
-A
2
Transformer (10) Check voltage X
1
-X
2
Check voltage H
1
-H
4
Thermostat (2) Check voltage
Fuse (7) Check voltage
Element (1) Check resistivity
Reduced (J)
hot water (K)
(L)
Ball valve closed (13, 14) Open ball valve
Filter clogged Clean filter
Air in the system Vent the system
Lukewarm (M)
water (N)
Fuse burned (7) Check continuity
Element failure (1) Check amperage
4.2 Solutions based on symptoms in fault table
Symptom Analysis Solution
(A)
(B)
(C)
(D)
(E)
(F)
(G)
(H)(M)
(I)(N)
No power Activate power
No continuity Replace on/off switch (6)
No continuity Replace delay timer (4)
No continuity Replace pressure switch (3)
A
1
-A
2
> 100 V, < 100 V T
1
-T
3
Replace contactor (5)
H
1
-H
4
> 200 V, X
1
-X
2
< 80 V Replace transformer (10)
No continuity in cold status Replace thermostat (2)
No continuity Replace fuse (7)
Resistivity nok Replace element (1)
4.3 Cold element resistivity by heater type (in Ohms)
Model Voltage
(kW) 208 V 240 V 400 V Y 480 V Y Ôƃƃp ÔÄƃp ÑŌÑp
12 11.41 Ω 13.55 Ω 12.48 Ω 16.88 Ω - - -
15 8.07 Ω 11.41 Ω 11.41 Ω 13.55 Ω - - -
18 6.93 Ω 9.32 Ω 8.07 Ω 12.48 Ω - 18.73 Ω -
24 11.41 Ω 13.55 Ω 13.55 Ω 20.53 Ω 9.32 Ω 13.55 Ω 20.53 Ω
27 9.32 Ω 12.48 Ω 11.41 Ω 16.88 Ω 8.07 Ω 12.48 Ω -
36 6.93 Ω 9.32 Ω 9.32 Ω - 6.93 Ω 9.32 Ω 13.55 Ω
48 11.41 Ω 13.55 Ω - - 9.32 Ω 13.55 Ω 20.53 Ω
54 9.32 Ω 12.48 Ω - - 8.07 Ω 12.48 Ω -
60 8.07 Ω 11.41 Ω - - 6.93 Ω 11.41 Ω -
72 6.93 Ω 9.32 Ω - - - 9.32 Ω 13.55 Ω
81 - - - - 9.32 Ω 12.48 Ω -
90 - - - - 8.07 Ω 11.41 Ω -
108 - - - - 6.93 Ω 9.32 Ω 13.55 Ω
120 - - - - 8.07 Ω 11.41 Ω -
144 - - - - 6.93 Ω 9.32 Ω 13.55 Ω
Depending on element type, hot resistivity may be 5% more than
cold resistivity.
ENGLISH
OPERATION
TROUBLESHOOTING