A.O. Smith GWV - 120 Installation And Service Manual page 84

Code + description Cause
E03 (lock-out error) The two temperature
sensors in the tank
detect a differential of >
Error in temperature
o
10 C over a period of
sensor T , outlet of
2
(1)
at least 60 seconds.
heat exchanger
E04 (lock-out error) The two dummy
sensors in the tank
detect a differential of >
Error in dummy
o
(2)
10 C over a period of
sensor .
at least 60 seconds.
E05 (lock out error) The controller has been
in a blocking error for at
least 20 hours.
Controller too long in a
blocking error
E07 (lock out error) Defective pump
Temperature difference
across the heat
Blocked or bunged up
exchanger too large
pipe system
Wrong pump mode
Note:
(1) Temperature sensor T is a '2 in 1' sensor; T
2
(2) The dummy flue gas sensor consists of dummy flue gas sensor 1 and dummy flue gas sensor 2.
Instruction manual GWV
Measures to take
1. Check sensor position and wiring.
2. If necessary, reset the electronic controller. Replace the sensor
if the error persists.
1. Check leads from dummy 1 and dummy 2.
2. If necessary, reset the electronic controller. Replace the dummy
sensor if the error persists.
1. Resolve the blocking error and press RESET to remove the lock
out error.
1. Check that the pump is working correctly
1. Replace blocked or distorted parts of the pipe system.
2. Clean the pipes to remove any lime accretions or baked-on dirt.
1. Check the pump operating mode according to the table
contains 2 NTCs for maximum thermostat and safety thermostat protection.
2
Comment
To replace the necessary parts, you must contact your installation
engineer
To replace the necessary parts, you must contact your installation
engineer
To resolve the blocking error, see fault description for the error
concerned.
To replace the necessary parts, you must contact your installation
engineer
For repairing and cleaning the pipe system, contact your installation
engineer.
If the error cannot be resolved or is persistent, contact your
installation engineer
is
84