CAC / BDP BW4BAH-105, Installation, Operation & Maintenance Manual

Page: 10 / 32

10
Adjust two throttling valves to maintain
at least 120°F in boiler return.
Throttling valves are used for bypass
piping, if required.
> 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
• Signi fi cant 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 fl oor
heating), a 3-way or 4-way mixing valve or suitable
alternative (e.g. Bypass Piping Arrangement shown
in diagram on following page) 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.