WARNING
Single wall Type C vent material is not approved for MPC boiler venting. When an MPC gas fired boiler is connected to a venting system that is designed so that it will operate under a negative pressure, manufactured vent systems, designed and approved for positive pressure application per UL1738, must be used (for example,
When an MPC oil fired or combination gas/oil fired boiler is connected to a venting system that is designed so that it will operate under a positive pressure, manufactured vent systems, designed and approved for positive pressure application, must be used (for example, Selkirk Metalbestos Model PS/ IPS,
Typical Vents that are used on Forced Draft Boilers, on Low Silhouette Buildings
VENT SIZING - Area must be the same as or greater than the boiler breeching (Smoke Outlet). A barometric damper may be required on installations with a high draft condition.
FAULTY BOILER BURNER OPERATION
1.If improper vent is suspected, remove pipe at breeching and operate boiler. This will determine if excessive down draft, blocked or restricted flue, etc. is causing the problem.
2.If using type shown in A above, be sure cap is raised sufficiently above main pipe to allow flue gases to vent unimpeded.
3.A popular type cap is shown in B.
4.The tee is frequently used as shown in C.
5.D and E should not be used due to possible fluctuations in back pressure.
Figure 3b: Vents - Faults and Suggestions
WARNING
Venting Instructions are recommendations only. Consult a venting expert on the design of a specific vent system for your application. The ASHRAE Venting Guide and The National Fuel Gas Code, NFPA 54 should be considered in all venting systems.
Conventional vent material may not be suitable for the application. Flue gases can leak carbon monoxide from the joints on these materials and can result in severe personal injury or death.
Installations having long horizontal runs or an excessive amount of tees or elbows will restrict the flow of combustion gases and can result in condensation, flue gas leakage of carbon monoxide, resulting in severe personal injury or death.
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