Venting

P38+ Pellet Stove

IMPORTANT NOTICE

Pellet Vent Pipe or PL Vent Pipe Must be used.

Fig. 7

+= Positive static pressure = Negative static pressure

Outside air flex pipe goes here

A combustion blower is used to extract the combustion gases from the firebox. This causes a negative pressure in the firebox and a positive pressure in the venting system as shown in fig. 7. The longer the vent pipe and more elbows used in the system, the greater the flow resistance. Because of these facts we recommend using as few elbows as possible and 15 feet or less of vent pipe. The maximum horizontal run should not exceed 48". If more than 15 feet of pipe is needed, the diam- eter should be increased from 3" to 4" because a larger pipe causes less flow resistance. Be sure to use approved pellet vent pipe and wall pass through fittings.

Vent Pipe

Pellet venting pipe ( also known as PL vent ) is con- structed of two layers with air space between the layers. This air space acts as an insulator and reduces the outside sur- face temperature to allow a clearance to combustibles of only 3 inches. The sections of pipe lock together to form an air tight seal in most cases; however, in some cases a perfect seal is not achieved. For this reason and the fact that the 38+ oper- ates with a positive vent pressure we specify that the joints also be sealed with clear silicone.

Outside Air

Outside air is optional except in mobile homes and where building codes require. The benefit of outside air is increased efficiency and should be used in small, or very well insulated homes.

To install outside air use 2 3/8" I.D. flex pipe part number 2-00-08543. There is a break-away hole on the rear panel which must be removed before connecting the flex pipe. The pipe should be run outside and terminate to the side or below the vent pipe outlet so the flue outlet is more than 12" from the inlet cover. The maximum length run of this pipe is 15 feet. If a longer run is needed the size must be increased to 3". Inlet cover part number 1-10-08542 should be used to keep bird, rodents etc. out of the pipe.

Flex pipe part# 2-00-08543

Inlet Cover part# 1-10-08542

HRV

When installing in a house with a Heat Reclaiming Ven- tilation System (HRV) be sure the system is balanced and is not creating a negative pressure in the house.

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Harman Stove Company PP38+ manual Vent Pipe, Outside Air