Bryant 340MAV Direct Venting, Removal of Existing Furnaces from Common Vent Systems, General

DIRECT VENTING

The 340MAV Furnaces require a dedicated (one 340MAV furnace only) direct-vent system. In a direct-vent system, all air for combustion is taken directly from outside atmosphere, and all flue products are discharged to outside atmosphere.

I.REMOVAL OF EXISTING FURNACES FROM COMMON VENT SYSTEMS

If furnace being replaced was connected to a common vent system with other appliances, the following steps shall be followed with each appliance connected to the venting system placed in opera- tion, while any other appliances connected to the venting system are not in operation:

1.	Seal any unused openings in the venting system.
2.	Inspect the venting system for proper size and horizontal
	pitch as required in the National Fuel Gas Code, ANSI

NOT IN HORIZONTAL SECTION

FURNACE

PIPE DIAMETER

TRANSITION IN

VERTICAL SECTION

A93034

Z223.1 or the CAN/CGA B149 Installation Codes and these

instructions. Determine that there is no blockage or restric-

tion, leakage, corrosion, and other deficiencies which could

cause an unsafe condition.

3. In so far as is practical, close all building doors and

windows and all doors between the space in which the

appliance(s) connected to the venting system are located

and other spaces of the building. Turn on clothes dryers and

any appliance not connected to the venting system. Turn on

any exhaust fans, such as range hoods and bathroom

exhausts, so they shall operate at maximum speed. Do not

operate a summer exhaust fan. Close fireplace dampers.

4. Follow the lighting instructions. Place the appliance being

inspected in operation. Adjust thermostat so appliance shall

operate continuously.

5. Test for draft hood equipped appliance spillage at the draft

hood relief opening after 5 minutes of main burner opera-

tion. Use the flame of a match or candle.

6. After it has been determined that each appliance connected

to the venting system properly vents when tested as outlined

above, return doors, windows, exhaust fans, fireplace damp-

ers, and any other gas-burning appliance to their previous

conditions of use.

7. If improper venting is observed during any of above tests,

the venting system must be corrected.

Vent system or vent connectors may need to be resized. For any other appliances when resizing vent systems or vent connectors, system or connector must be sized to approach minimum size as determined using appropriate table found in the NFGC or NSC-

NGPIC.

II.COMBUSTION-AIR AND VENT PIPING

A.General

Combustion-air and vent pipe fittings must conform to American National Standards Institute (ANSI) standards and American Society for Testing and Materials (ASTM) standards D1785 (schedule-40 PVC), D2665 (PVC-DWV), D2241 (SDR-21 and SDR-26 PVC), D2661 (ABS-DWV), F628 (schedule-40 ABS), or F891 (PVC-DWV cellular core). Pipe cement and primer must conform to ASTM standards D2564 (PVC) or D2235 (ABS). See Table 6 for maximum pipe lengths and Fig. 30, 31, 32, 33, and 34 for exterior piping arrangements.

In Canada construct all combustion-air and vent pipes for this unit of CSA or ULC certified schedule-40 PVC, PVC-DWV or ABS-DWV pipe and pipe cement. SDR pipe is NOT approved in Canada.

NOTE: Furnace combustion-air and vent pipe connections are sized for 2-in. pipe. Any pipe size change should be made outside furnace casing in vertical pipe. (See Fig. 26.) This allows proper drainage of vent condensate.

Ð21Ð

Fig. 26ÐCombustion-Air and Vent Pipe Diameter

Transition Location and Elbow Configuration

Combustion-air and vent pipes must terminate together in same atmosphere pressure zone, either through roof or sidewall (roof termination preferred), using accessory termination kit. See Table 5 for required clearances.

TABLE 5ÐCOMBUSTION-AIR AND VENT PIPE

TERMINATION CLEARANCES

LOCATION	CLEARANCE (FT)
	U.S.A.	Canada
Above grade level or above antici-	1	1²
pated snow depth
Dryer vent	3	3
From plumbing vent stack	3	3
From any mechanical fresh air	1	6
intake
For furnaces with an input capac-
ity less than 100,000 BtuhÐfrom
any non-mechanical air supply	1	1
(windows or doors which can be
opened) or combustion-air open-
ing
For furnaces with an input capac-
ity greater than 100,000
BtuhÐfrom any non-mechanical	1	3
air supply (windows or doors
which can be opened) or
combustion-air opening
From service regulator vent, elec-
tric and gas meters, and relief	4*	6³
equipment
Above grade when adjacent to	7	7
public walkway

* Horizontal distance.

² 18 in. above roof surface in Canada.

³36 in. to electric meter in Canada only.

NOTES:

1. If installing 2 adjacent 340MAV Furnaces, refer to Multiventing and Vent Terminations section for proper vent configurations.

2. When locating combustion-air and vent terminations, consideration must be given to prevailing winds, location, and other conditions which may cause recirculation of the appliance's own flue products or the flue products of adjacent vents. Recirculation can cause poor combustion, inlet condensate problems, and accelerated corrosion of heat exchangers.

Furnace combustion-air and vent pipe connections must be at- tached as shown in Fig. 27. Combustion-air intake plug fitting and inducer housing alternate vent cap may need to be relocated in some applications.

NOTE: Slope combustion-air and vent pipes a minimum of 1/4 in. per linear ft with no sags between hangers.