Pipe Tankless Heaters - Weil-McLain 88 Manual

Boiler manual: • Installation

Pipe tankless heaters

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
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.
Part No. 550-100-068/1009
• Start-Up • Maintenance
must
comply with valve
• Parts
To pipe tankless heaters:
1. See Figure 35.
2. Size piping no smaller than heater inlet and out-
let.
3. Automatic mixing valve must be installed. See
Figure 35. Follow manufacturer's instructions to
install.
4. Flow regulating valve must be installed. Size accord-
ing to continuous draw of heater. See Figure 34.
Follow manufacturer's instructions to install.
5. Operating control with small adjustable differen-
tial scale is recommended. Install in temperature
control tapping in heater plate.
6. Multiple tankless heaters (see
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.
Figure 34
Tankless heater ratings (Weil-McLain
ratings)
Heater Intermittent Continuous
number draw – GPM draw GPM
(note 2) (notes 1, 2)
820 8.5
GPM based on 40–140°F DHW with boiler water
Note 1
at 200°F
Note 2 Based on continuous draw with no recovery period
Figure 35
Tankless Heater Piping
Figure 35):
Inlet and
outlet tappings
8.0 ¾"
25