Table 6
Tankless heater ratings
Boiler
model
number
Heater
number
Intermittent
draw
ratings
(gpm)*
Inlet
and outlet tapping sizes
SGO-3
35-S-29
3.25
¾"
SGO-4
35-S-29
3.50
¾"
SGO-5
35-S-29
3.75
¾"
SGO-6
35-S-29
4.00
¾"
SGO-7
35-S-29
4.00
¾"
SGO-8
35-S-29
4.00
¾"
SGO-9
35-S-29
4.00
¾"
Note 1
To avoid supplying steam to system during summer tankless operation, raise water level to one inch
above normal water line.
Note 2
Gallons of water per minute heated from 40°F to 140°F with 200°F boiler water temperature. Tested in
accordance with I=W=H testing and rating standard for indirect tankless water heaters tested with boilers.
To pipe tankless heater
1. Size piping no smaller than tankless heater inlet
and outlet.
2. Following controls (furnished by others) must be
installed:
a. Automatic mixing valve. See Figure 14.
(Read
at left.)
b. Flow regulating valve. Size according to inter-
mittent draw of tankless heater. See Table 6be-
low. Follow valve manufacturer’s instructions
to install.
3. Additional anti-scald devices may be installed at
each hot water faucet, bath and shower outlet.
4. In hard water areas, soften cold domestic supply
water to heaters to prevent lime build-up.
Connect tankless heater piping
Hot Water Can Scald!
•
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 sanitiz-
ing 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 adjust-
ment.
Studies have indicated that danger-
ous bacteria can form in potable
water distribution systems if certain
minimum water temperatures are
not maintained. Contact local health
department for more information.
Part number 550-141-829/1211
22
GOLD
SGO
OIL-FIRED NATURAL DRAFT STEAM BOILER — SERIES 3 —
Boiler Manual
SERVICE TECHNICIAN ONLY — read and follow completely.
