Raypak 751 manual Horizontal Thru-wallDirect Vent Termination, ·45′ of straight flue pipe

ÁDB-1501

Table M: Horizontal Thru-wall Direct Venting without Add-on

Secondary Condensing Heat Exchanger

Horizontal Thru-wall Direct Venting System (Category III) Installation

These installations utilize the boiler mounted blower to draw combustion air from outdoors and vent combus- tion products to the outdoors.

The total length of the thru-wall exhaust vent cannot exceed forty-five (45) feet in length for the flue outlet. Each elbow used is equal to ten (10) feet of straight pipe. This will allow installation in one of the three fol- lowing combinations:

·45′ of straight flue pipe.

·35′ of straight flue pipe and one elbow.

·25′ of straight flue pipe and two elbows.

The total length air supply pipe cannot exceed forty- five (45) feet in length for the combustion air inlet. Each elbow used is equal to ten (10) feet of straight pipe. This will allow installation in one of the three fol- lowing combinations:

·45′ of straight combustion air pipe

·35′ of straight combustion air pipe and one elbow.

·25′ of straight combustion air pipe and two elbows.

The direct vent cap is not considered in the overall length of the venting system.

Care must be taken during assembly that all joints are sealed properly and are airtight.

The vent must be installed to prevent the potential accumulation of condensate in the vent pipes. It is rec- ommended that:

a)The vent be installed with a slight downward slope of not more than 1/4" per foot of horizontal run to the vent terminal.

b)The vent be insulated through the length of the horizontal run.

For appliances installed in extreme cold climate, it is recommended that:

a)The vent be installed with a slight upward slope of not more than 1/4" per foot of horizontal run to the vent terminal. In this case, an approved conden- sate trap must be installed per applicable codes.

b)The vent be insulated through the length of the horizontal run.

Horizontal Thru-wall Direct Vent Termination

The direct vent cap MUST be mounted on the exterior of the building. The direct vent cap cannot be installed in a well or below grade. The direct vent cap must be installed at least one (1) foot above ground level and above normal snow levels.

Multiple direct vent caps MUST NOT be installed with one combustion air inlet directly above a direct vent cap. This vertical spacing would allow the flue prod- ucts from the direct vent cap to be pulled into the combustion air intake installed above.

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