• Installation •
10 Pipe tankless heaters
To pipe tankless heaters:
1.Size piping no smaller than heater inlet and outlet.
2.Automatic mixing valve must be installed. See Figure 26. Follow manufacturer’s instructions to install.
3.Flow regulating valve must be installed. Size according to continuous draw of heater. See Table 10. Follow manufacturer’s instructions to install.
4.Operating control with small adjustable differential scale is recommended. Install in temperature control tapping in heater plate.
5.Multiple tankless heaters (see Figure 26):
a.Use cold water supply header with individual risers to each heater. Size header by increasing one pipe size for each additional heater.
b.Use hot water outlet header with individual risers to each heater. Size header by increasing one pipe size for each additional heater.
c.Do not pipe multiple heaters in series.
6.In hard water areas, soften cold domestic water supply to heaters to prevent lime
Hot water can scald!
Table 10 Tankless Heater Ratings
Tankless | Continuous draw | Inlet and outlet |
heater model | (no recovery period) | tappings |
| GPM |
|
6.5 | ¾" | |
|
|
|
Figure 26 Tankless Heater Piping
•Consumer Product Safety Commission and some states recommend domestic hot water temperature of 130°F or less.
•When installing an automatic mixing valve, selection and installation must comply with valve manufacturer's recommendations and instructions.
•Water heated to a temperature suitable for clothes washing, dish washing and other sanitizing needs will scald and cause injury.
•Children, elderly, infirm or physically handicapped persons are more likely to be injured by hot water. Never leave them unattended in or near a bathtub, shower or sink. Never allow small children to use a hot water faucet or draw their own bath. If anyone using hot water in the building fits this description, or if state laws or local codes require certain water temperatures at hot water faucets, take special precautions:
—Install automatic mixing valve set according to those standards.
—Use lowest practical temperature setting.
—Check water temperature immediately after first heating cycle and after any adjustment.
Part No. | 27 |