Rinnai INFINITY 26i Service Manual page 37

P. Surge Protection sub pcb
The surge protection sub pcb is located in a small white box on the front of the main pcb. It is
below the dip switches. If you follow the main power cable into the unit it will lead you to the
surge protection sub pcb
After checking to be sure there is power incoming (240 Vac on the bottom connection
between blue and brown) check the top connector of the surge protector. Put your meter
leads into the plug (while it is connected) with the two white wires. You should get 207 – 274
Vac. If not and you have incoming mains to the bottom of the surge protector, replace the
surge protector.
Q. Transformer.
There is one transformer on the 26i located in the back behind the pcb. To access it remove
the top and bottom screw holding in the pcb and pull the pcb out. Let it hang from its wires,
but be careful not to damage it or pull on it.
Test the transformer in standby mode (unit on, water off.)
First check the voltage from the surge protection sub pcb. This is detailed in section P. The
blue and brown wires from the surge protector go directly to the transformer, so if there is
power from the surge protector there is power to the transformer (check for loose
connections.) From the transformer come two wires, black and white. These run back to the
pcb. As the pcb is already out, you can check the voltage from the transformer at the pcb.
With your meter check Voltage AC by putting your leads in to the connector (while
connected) of the black wire and the white wire (with a grey wire as well.)
The voltage from Black – White should be about 100Vac.
For this unit the 100Vac to low voltage dc is done on the pcb. If you need to verify there is
low voltage dc follow the procedure for the water flow sensor (J) and check for 12 Vdc signal
between black and red.
R. Filter.
Below the water heater, on the cold water connection is a brown plug. Isolate the water supply
and remove this brown plug. It holds a small micron basket strainer. The strainer becomes
clogged easily, especially after installation. When it is clogged sometimes water will travel
through the unit without triggering the flow sensor. Make sure you check any external Y-
strainers as well
Infinity 26i and HD50i