Project Guide

How to Install an On-Demand Water Heater

1
RUN POWER FOR THE UNIT
Run power for the unit - On-Demand Water Heater
  • You must utilize either a 120- or 240-volt circuit, wholly devoted to the heater. 
  • Both voltages require 8-gauge wire, and the section exposed to the area under the sink must be armored cable. 
  • If the manufacturer's instructions call for a larger cable, the National Electrical Code says you must comply.
2
UNDER SINK INSTALLATION
Under sink installation - On-Demand Water Heater
  • If you’re installing the heater under an existing sink, turn off the water line and drain the line by opening a faucet at a lower point somewhere in the house. 
  • Solder a cutoff valve onto the pipe stub that comes from the floor or wall. 
  • Solder a second valve onto what's left of the line that runs to the faucet, cutting the line as necessary to allow room for the heater.
3
SCREW THE UNIT TO THE WALL
Screw the unit to the wall - On-Demand Water Heater
  • Connect the water supply line to the cold in-feed fitting with soldered copper pipe or high-pressure flex connections. 
  • Wrap Teflon tape around the threads before you make the connection and hand-tighten. 
  • Finish tightening with a wrench. 
  • Connect the line going to the faucet to the hot water outlet using the same materials.
4
WIRE THE UNIT
Wire the unit - On-Demand Water Heater

On a 240-volt unit: 

  • The white wire will attach to one of the hot terminals and the black to the other hot terminal - they're often labeled L1 and L2. 
  • The ground will go to the grounding screw on the unit. 


On a 120-volt unit: 

  • Twist the white supply wire to the white wire in the unit, and twist the black wire to the black. 
  • Cover with wire caps, and tape the caps in place.