11
> LOW DESIGN WATER TEMPERATURE
SYSTEMS
> LARGE WATER CONTENT SYSTEMS
> PIPING ARRANGED FOR “POWER
PURGING” AIR OUT OF THE SYSTEM
PIPING, REFER TO THIS MANUAL’S
SECTION ON “FILLING THE SYSTEM
WITH WATER” OPTION #1
SYSTEM PIPING
Figure 7 - Bypass Piping Arrangement Diagram
Low Design Water Temperature Systems (Below 140°
F) And Large Water Content Systems
Significant condensation may form in this boiler and/
or venting system if boiler is operated with return
temperatures of less than 120° F.
Condensation is corrosive and can eventually cause damage
to boiler and venting system. Minimum design return water
temperature to prevent this condensation in boiler and
venting is 120°F.
Boiler used in heating system where design water
temperatures below 140°F are desired (e.g. radiant floor
heating), a 3-way or 4-way mixing valve or suitable
alternative (e.g. Bypass Piping Arrangement as shown in
Figure 7) is required to prevent low temperature (below
return 120°F) return water from entering boiler. When
using mixing valve, follow manufacturer’s installation
instructions.
Boiler connected to system having large water content
(such as former gravity system), use of Bypass Piping
Arrangement shown in diagram on following page is
suggested.
PN 240013023, Rev. B [12/31/2020]
