Rinnai INFINITY 26i Service Manual page 38

S. Water flow.
To operate there must be at least 2.4 l/min flowing through a Rinnai water heater. If there is
multiple heaters, installed without PAM valves or a MECS system then there must be 2.4
l/min per heater. A modern wash hand basin could be as low as 3 or 4 l/min, so if there is no
means of staging the heaters they may not operate. Isolate all the units except one to find out.
This problem could also crop up with a pumped secondary. Make sure the combination of the
pump capacity, and the staging of the units is compatible.
The flow rate from your tap can be determined with a Weir cup, or a deluxe controller. The
deluxe controller manual explains the diagnostics function. If you are not getting enough flow
at an outlet, and you used to, check the filter (R.)
T. Gas Supply.
If the unit suddenly goes off you will need to check the gas supply. This is easy when
operating on natural gas, and is done by checking the inlet pressure. Other things to check are
the meter size, compared to other appliances total offtakes. If the unit has just been installed
there may be air in the line, be sure it is fully purged.
If the unit is on LPG make sure that you visually examine the tank or bottles to be sure they
are not freezing up. If they are then there is not enough gas. Check the regulators to be sure
they will pass enough gas for the system.
For both LPG and natural gas you will need to confirm that the gas pipe size is correct. You
may need to check the gas filter (F.)
U. Check anti frost heater components
The unit has five frost protection heaters mounted on the water pipes to protect them from
freezing. The heaters are white ceramic resistive heaters, and come on around 5°C. The
voltage through the heaters, when active, is 240Vac. The heaters are located as follows.
There is a valve heater in the mains incoming (where the flow sensor is) and another valve
heater in the outgoing hot water valve (next to the hot water thermistor.) There are two
square pipe heaters, on the left side of the water heater, one on the mixed water pipe (heat
exchanger + bypass), and one on the bypass. The fifth one is located on the front of the unit,
at the top on the heat exchanger outlet.
Each heater element can be tested by measuring the resistance through them one at a time.
The valve heater resistance should be 50 – 56 k Ohms
The square heaters and the other valve heater should be 444 – 510 k Ohms
The entire anti frost heater system is done as a kit, so the easiest check is to see if they heat up
when the sensor is closed. If not, replace the system. There will be 240 Vac through the
heaters if the system is working so take care.
Infinity 26i and HD50i