Weil-McLain 2 Series Manual page 28

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SlimFit Series 2
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.
Weil-McLain recommends the use of a Variable Speed Chimney Fan / Power venter to ensure that the appropri-
ate negative pressure range is kept for Category II venting. The reason this may be needed is due to the higher
efficiency of the SlimFit boiler. The exhaust gas temperatures are lower which result in less draft when using a
chimney fan/power venter. A flow proving switch should be wired into the LCI circuit on the boiler. The use of
this device should be considered in any engineered vent system in accordance to local authority having jurisdic-
tion.
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 tem-
perature from the SlimFit boiler. The use and set-point of this shall be determined by the system designer in
accordance to 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.
28
COMMERCIAL CONDENSING GAS
- — Boiler Manual
FIRED WATER BOILER
Part number 550-100-180/0917