Rinnai INFINITY 26i Service Manual page 39

V. Frost Sensing Switch
The frost sensing switch is located a short distance upstream (to the right) of the long,
cylindrical frost heater. It is a black, top hat style bi-metal switch. It is a normally open
contact so to prove it is working it must be cooled to about 5°C. At this temperature the
resistance in the switch can be tested, it should be less than 1 Ohm.
W. Check Flue
If there are combustion problems they could be due to the flue. Is the flue too long? The
maximum flue run is 15m, less 2m per bend, to a maximum of 4 bends. Regardless of the
length of flue the maximum height off the water heater to the terminal is 9m. If there is a
condensate trap installed, be sure it is the right way up (with the male section at the bottom.)
Infinity 26i and HD50i