Weil-McLain SVF 1500 Manual page 30

SVF
™
Series 1
Commercial Condensing Gas-Fired Water Boiler — Boiler Manual
Venting/combustion air — options
Improper Installation of a Category II vent system resulting in positive pressure in the vent system can result in
flue gas spillage and carbon monoxide emissions, causing severe personal injury or death.
In applications where the venting system cannot maintain the required negative pressure on the boiler outlet via
natural draft, Weil-McLain recommends the use of a Variable Speed Chimney Fan / Power venter to ensure that
the appropriate negative pressure range is kept for Category II venting. The reason this may be needed is due to the
higher efficiency of the
a chimney fan/power venter. A flow proving switch should be wired into the Closure Switch on terminal block
P11 of the boiler. The use of this device should be considered in any engineered vent system in accordance to local
authority having jurisdiction.
Weil-McLain recommends the use of a Double Acting Barometric Damper or Modulating Damper to ensure the
appropriate negative pressure range is kept for Category II venting. The use of this device should be considered in
any engineered vent system in accordance to local authority having jurisdiction.
When using a damper of any kind, it is recommended to use a thermal spill switch to detect any exhaust flow into
the boiler room. Verify the temperature range on the thermal spill switch is adequate for the Flue gas temperature
from the SVF
local authority having jurisdiction.
Code Compliance
Venting / Combustion air piping – Installations must provide provisions for combustion and ventilation air in
accordance with the section "Venting of Equipment", of the National Fuel Gas Code, ANSI Z223.1/NFPA 54, or
"Venting Systems and Air Supply for appliances" of the Natural Gas and Propane Installation Code, CAN/CSA
B149.1, or applicable provisions of the local building codes.
30
TM
SVF boiler. The exhaust gas temperatures are lower which result in less draft when using
TM
boiler. The use and set-point of this shall be determined by the system designer in accordance to
Part number 550-100-250/0819