Hvac / Heat Pumps
Ariston 10.5kW Electric Tankless Water Heater User Manual
Comprehensive installation, operation, and maintenance guide for the Ariston 10.5kW electric tankless water heater. Includes safety instructions, troubleshooting, and technical specifications.
Table of contents
Manual images
Jump to the sectionProduct Overview
The Ariston 10.5kW electric tankless water heater is designed for indoor use to provide efficient, on-demand hot water. This unit must be installed by a qualified and licensed professional in accordance with all local, state, and national electrical and plumbing codes. It is not intended for use as a pool heater.
Safety Information
Warning: Improper installation or failure to follow instructions can result in severe personal injury, death, or substantial property damage. The unit must be properly grounded and connected to a dedicated circuit breaker. Do not install the heater where it may be exposed to freezing temperatures, direct sunlight, rain, or splashing water. If the unit has been submerged in water, it must be replaced immediately.
Installation
The plumbing installation must be completed before the electrical connection. The unit requires metal pipes or reinforced hoses capable of withstanding at least 116 psi. A pressure relief device (PRD) must be installed at the inlet of the water supply line. Ensure the unit is mounted vertically on a solid, level surface with the water inlets and outlets at the bottom. Maintain minimum service clearances of 24 inches in front, 6 inches on top and right, 24 inches on the left, and 12 inches at the bottom.
Operation and Maintenance
Before turning on the power, ensure the tank is completely filled with water to prevent dry-firing, which will damage the heating element and void the warranty. The water temperature is adjusted via the knob on the front cover. For safety, especially in households with children or elderly persons, it is recommended to set the temperature to 120°F or lower and consider installing a mixing valve to prevent scalding. Annual inspection by a qualified technician is recommended. Maintenance tasks such as descaling the heating element may be required depending on water quality.
Troubleshooting
If the water is not hot enough, check for excessive flow rates, low temperature settings, or blocked water supply lines. If the unit shuts off during use, check the power supply and circuit breaker. If the high-limit switch trips, it may need to be manually reset by a qualified technician.
Manufacturer information
Ariston
Practical help
Common problems
Water not hot enough
Reduce flow rate at the faucet, increase temperature setting, or ensure shutoff valve is fully open.
Water too hot
Increase flow rate at the outlet or switch to a lower temperature setting.
Heater shuts off during use
Check power supply and circuit breaker.
Water stops flowing
Ensure main water shutoff valve is fully open and there are no obstructions.
No hot water with supply line open
Check power, ensure flow rate is at least 0.5 gpm, or reset high limit switch.
Before use
- Ensure unit is grounded.
- Verify plumbing installation is complete.
- Install the included pressure relief device (PRD).
- Ensure the tank is completely filled with water.
- Purge air from the heater and piping.
- Check all connections for leaks.
- Confirm circuit breaker size and wire gauge match specifications.
Specs in practice
- Minimum Water Flow
- 0.55 gpm is required to activate the heating element.
- Working Pressure
- Operating range is 7 - 115 psi.
- Temperature Range
- Adjustable between 90°F and 131°F.
- Water Connections
- Standard 1/2 inch NPT fittings.
Images and diagrams
- Figure 2: Shows correct installation of the Pressure Relief Device (PRD) on the cold water inlet.
- Figure 5: Illustrates wire knockout locations and mounting points for the unit.
- Figure 8: Provides a detailed piping diagram including shut-off valves, mixing valves, and drain pan.
- Figure 10: Displays the internal wiring schematics for different power models.
- Figure 12: Identifies the location of the high-limit reset switches.
Model compatibility
- Approved for indoor installation only; not for pool heating.
- Requires dedicated circuit breaker on the main electrical panel.
- Must be installed vertically with inlets/outlets at the bottom.
- Water chemistry must meet specific pH and mineral content requirements to maintain warranty.
Manual page author
Michael Turner
Technical manual editor
Reviews PDF manuals for structure, safety notes, and practical product details so readers can find the right information quickly.