Worcester GREENSPRING CWi47 Installation And Operating Instructions Manual page 53

Display Cause
Hot water temperature sensor
(NTC) on the hot water outlet
of the appliance detect a high
temperature of the hot water.
Temperature > 85°C
Cold water inlet temperature
sensor fault.
Flue gas temperature sensor -
the burner will be locked if the
reading gets over 90°C.
Burner backflow temperature
sensor over 130°C.
The appliance will lock out the
burner.
High temperature sensor
(ECO) open circuit (resets
when lower temperatures than
104 °C are detected ).
Tab. 27
* By qualified registered gas engineer only.
6 720 646 322 (2012/05)
Solution
1. Check the sensor is located and fixed correctly.
2. Check the electrical connections and connectors of the hot
water temperature sensor. Clean terminals. If the terminals are
corroded, replace the sensor and cables. Check electrical
resistance ( Fig. 3, pos. 2).*
3. Clean the water filter, any dirt in the taps and also the water
filters of the installation.
4. In areas where water has a high mineral content, periodic
descaling may be necessary.*
1. Check connector on wires coming from top of water valve
for a secure connection.
2. Sensor may trip if water temperature drops below 2°C.
Protect heater from freezing conditions as any damage caused
by freezing conditions is not covered by the warranty.
3. Check temperature sensor for any visible damage.
1. Check and clean the primary heat exchanger.
2. Check and clean the condensing heat exchanger.
3. Reduce maximum output.
4. Reduce water temperature setpoint.
1. Check flue gas system.
2. Check if secondary fan connections are connected.
3. Check if flue requirements are met. Long flue lengths,
flueing with more than three elbows, blocked flue pipes or
cross ventilation may cause this fault.
4. Call Technical Support.
1. Disconnect power supply and check wiring connections on
the overheat sensor and the two connectors on the control
board. ( Fig. 2, pos. 7).
2. Check white wiring connections at the overheat sensor.
Clean the terminals. If badly corroded, replace sensor and
wiring harness.*
3. Check that flue requirements are met. Long flue lengths,
flueing with more than three elbows, blocked flue pipes or
cross ventilation may cause this fault.
4. Clean the water filter, any dirt in the faucets and also the
water filters in the installation.
5. In areas where water has a high mineral content, periodic
descaling may necessary.*
6. Disconnect power supply to the water heater. Open a hot
water tap for several minutes to allow cold water to pass
through heat exchanger. Close hot water tap and disconnect
lead wires to overheat sensor. Using a multimeter, check
continuity through the overheat sensor contacts. Replace
sensor if continuity shows up.
FAULT FINDING AND DIAGNOSIS
53