Loading ...
Loading ...
Loading ...
Boiler manual: • Installation • Start-Up • Maintenance • Parts
25Part No. 550-110-275/1018
Pipe tankless heaters
Figure 30 Tankless heater ratings (Weil-McLain ratings)
Heater
number
Intermittent draw
– GPM
(note 2)
Continuous draw
GPM
(notes 1, 2)
Inlet and
outlet
tappings
590-921-910 9 11 ¾"
Note 1 GPM based on 40–140°F DHW with boiler water at 200°F.
Note 2 Based on continuous draw with no recovery period.
Figure 31 Tankless Heater Piping
NSF/ANSI 372
Tankless water heaters for the 94 boilers
have been tested and certified by CSA
Group (certificate # 2552127).
To pipe tankless heaters:
1. See Figure 31.
2. Size piping no smaller than heater inlet and outlet.
3. Automatic mixing valve must be installed. See Figure 31.
Follow manufacturer's instructions to install.
4. Flow regulating valve must be installed. Size according
to continuous draw of heater. See Figure 30. Follow
manufacturer's instructions to install.
5. Operating control with small adjustable differential
scale is recommended. Install in temperature control
tapping in heater plate.
6. Multiple tankless heaters (see Figure 31):
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.
7. In hard water areas, soften cold domestic water supply
to heaters to prevent lime build-up.
Hot water can scald!
Consumer Product Safety Commission and some
states recommend domestic hot water tempera-
ture of 130°F or less.
When installing an automatic mixing valve, se-
lection and installation
must comply with valve
manufacturer's recommendations and instruc-
tions.
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 handi-
capped 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.
Loading ...
Loading ...
Loading ...