Apply model-specific water and flue limits, commission safely and distinguish cleaning from fault clearing.
Installation and maintenance decisions depend on the particular continuous-flow heater. The examples here use the Rinnai UK A-Series 11i, 17i and 17e; they do not transfer unchanged to older Rinnai ranges or other manufacturers.
Use the complete appliance procedure for gas work, electrical isolation, servicing and the checks before return to use. The points below explain the decisions behind that work.
Water supply: pressure and capacity
For this range, incoming water pressure above 8 bar needs a pressure-reducing valve. A relief valve releases excess pressure, a check valve prevents reverse flow and a strainer removes debris. These functions do not replace regulation of the incoming supply.
The manual specifies 0.8 bar for rated maximum flow. The heater can run below that pressure, but lighting does not mean it can deliver its full flow. Check the water flow available in use as well as the pressure.
Match the exhaust arrangement to the model
The 17e outdoor model discharges directly outdoors and must not have a flue system added. Give it the specified open-air location and clearances. A short extension or a flue intended for an indoor heater is not an approved alternative.
The 11i and 17i require an approved flue system. Check both the equivalent length and the separate bend limit:
- 11i: up to 2.5 m equivalent length, with no more than one 90° bend.
- 17i: up to 6.5 m equivalent length, with no more than three 90° bends.
Each 90° bend uses 0.5 m of the equivalent-length allowance. For example, 4 m of straight run and two such bends total 5 m equivalent length. For a 17i, this meets the two limits above; it still needs to satisfy the remaining layout, component and terminal requirements. Spare length allowance never authorises an extra bend beyond the model’s bend limit.
Where the exhaust run exceeds 1.5 m, the manual recommends a condensate siphon kit to remove water that can collect as the exhaust cools. Condensate can form in a flue even when the appliance is not a condensing model. Follow this range’s arrangement rather than applying a condensing boiler’s details automatically.
Commissioning without exposing users to hot water
For the specified inlet gas-pressure test, the A-Series procedure selects maximum delivery temperature and opens the available hot outlets. Prevent occupants from accessing those outlets during the test: the discharge can scald. Complete the other prescribed test conditions, including the operating load on the gas supply.
The appliance’s electronically controlled gas regulator is factory-set and requires no installation adjustment. A poor supply reading calls for investigation of the installation and the specified diagnostic procedure. Turning the appliance regulator is not a remedy for inadequate supply pipework.
Confirm the actual hot-water delivery temperature with a thermometer. The controller’s selected figure does not measure the temperature at a tap after pipe losses. Test the remote functions, explain them to the user and complete the commissioning record.
Cleaning and scale
After safe isolation and cooling, the specified dust-removal method for the main burner, heat exchanger and fan blades uses pressurised air. Keep wet cloths and spray cleaners off the burner. Renew the combustion-chamber gasket whenever the chamber is opened for cleaning, then complete the prescribed reassembly and operating checks.
The motors are permanently lubricated. They still need to be kept clean, but periodic oiling is not required. Dust removal and lubrication are separate maintenance tasks.
An LC code identifies scale in the heat exchanger. In maintenance history, 00 replaces the LC part of that indication; it does not mean the test was passed or that there was no fault. Follow the flushing procedure and assess water treatment. Repeated scale warnings can lead to lockout, and clearing a display does not remove deposits.
During chemical flushing, isolate the building’s hot- and cold-water connections as specified. For the subsequent fresh-water rinse, move the discharge hose out of the solution pail to a suitable drain. Keep the building’s hot-water side isolated so the remaining solution leaves through the service hose. Follow the full rinse duration, filter-cleaning and restoration sequence before use.
After freezing
Do not operate a heater whose water passages or connected pipes are frozen. Follow the isolation procedure and allow them to thaw. Inspect the heater and the pipework for leaks before returning them to use: water can flow again through a split waterway. Follow the model’s frost precautions when leaving it unused.