Boulter Buderus Benchmark 600-28C Installation And Servicing Instruction page 52

5 Servicing
5.3.8 Checking the bi-sensor, return sensor and
hot water sensors.
Remove the cable connection (see fig. 74) of the bi-sensor.
Measure the resistance of both parts of the bi-sensor
(see fig. 75).
Disconnect the return sensor (see fig. 76).
Subject to modifications resulting from technical improvements!
52 Installation and maintenance instructions for wall-mounted condensing gas boiler 600 - 28C • 01/2004
fig. 74 Remove cable connection of bi-sensor
fig. 75 Measure resistance of bi-sensor
fig. 76 Disconnect return sensor
Boulter Buderus Ltd. • http://www.boulter-boilers.com