11
IM-BW4-5-02
[240013014 Rev. B [12/15/2020]
SYSTEM PIPING
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 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.
