Buderus 800-24 Installation And Servicing Instructions page 50

5 Servicing
5.3.9 Checking the flow, return, safety and mains-water
sensors
Unplug cable connection from sensor.
Measure resistance of sensor.
Use a second-reading thermometer to measure the
temperature around the sensor.
Check readings against values shown in table 10
(see page 51). If there is any mismatch, the sensor is
defective.
If the sensor is working correctly, plug it in once more.
Subject to modifications resulting from technical improvements !
50 Installation and servicing instructions condensing gas boiler 800 - 24/29/43/60 and 800 - 24T25/29T25 H/V • edition 02/2006
fig. 64 Checking the flow/return sensors
fig. 65 Checking the safety sensors
fig. 66 Checking the mains-water sensor
Buderus • http://buderus-domestic.co.uk