Bosch Appliances 250SX NG, 250SX LP manual B Attach the flue gas exhaust accessory 8 705

Appliance details

The appliance should be located as close to the point of termination as possible. The maximum vent length is 26 feet (8 m) with one 90 degree elbow. Subtract 2½ feet from the total vent length for each additional 90° elbow used (a maximum of three 90° elbows are permitted in the total vent length), or subtract 1 ¼ feet for every 45° elbow used. Horizontal sections of vent must pitch ¼" for every foot of horizontal length and be supported at 4 foot intervals with overhead hangers.

Note: Listed thimbles or collars are necessary to pass through wall and ceiling partitions. If the vent system passes through combustible areas where the vent clearance requirements cannot be maintained, it is permissible to chase straight sections of sealed 3 inch single wall vent through 4 inch (or greater) Type-B vent. The distance to combustibles using this chase technique is 1 inch. Note: Type-B vent should never be used as the actual exhaust vent system for the appliance, as it is not gas tight.

Minimum exhaust vent size and length

The use of a 90 degree elbow is equivalent to 2 ½ ft in vent length.

The use of 45 degree elbow is equivalent to 1 ¼ ft in vent length.

Fig. 8

Maximum exhaust vent and combustion air inlet lengths

Fig. 9

Note: reduce 2½ ft for each 90° elbow used after the first one, reduce 1 ¼ ft for each 45° elbow.

Vent Safety System

The 250 SX will shut down if inadequate exhaust venting is detected or a lack of combustion air is provided to the unit; see troubleshooting section on

page 24. See error code to confirm error, correct the problem and then reset the heater before operating.

Attaching the exhaust and air inlet connection adaptors to the top of the heater

Fig. 10

Fig. 11

BAttach the flue gas exhaust accessory (8 705 504

114)to the top of the unit (position 1) using the 4 screws and gasket provided, and fully insert 3" stainless steel vent pipe into the accessory and tighten the clamp (position 2).

B Attach the combustion air inlet accessory (8 705 504 115) to the top of the unit (position 3) using the 3 screws and gasket provided, and fully insert 3" combustion air pipe into the accessory and tighten the clamp (position 4). NOTE: The appliance has the possibility to mount the combustion air inlet accessory on the top right or on the top left side of the heater. The combustion air inlet that is not used must be kept sealed.

2.9.1Venting options

Installing this water heater as a room sealed (TWIN PIPE SYSTEM) is the recommended method. Contact CEC or dealer for available vent termination kits and vent materials for this water heater.

Exhaust venting shall be done with 3”

istainless steel (AL29-4C) vent pipe.

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