Operation & Installation Manual 09/2002

Table 8—Maximum Allowable Exposed Vent Pipe Length (ft) With and Without Insulation in Winter Design

Temperature Ambient*

UNIT

SIZE

060

080

100

120

WINTER DESIGN

TEMPERATURE

(°F)

20

0

-20

20

0

-20

20

0

-20

20

0

-20

20

0

-20

20

0

-20

20

0

-20

MAX PIPE

DIAMETER

(IN.)

2

2

2

2

2

2

2.5

2.5

2.5

2.5

2.5

2.5

3

3

3

3

3

3

4

4

4

WITHOUT

INSULATION

44

21

20

55

30

16

58

29

14

40

38

21

63

30

12

70

38

19

65

26

5

WITH 3/8–IN. OR

THICKER INSULATION†

70

70

57

55

55

55

70

70

67

40

40

40

70

70

70

70

70

70

70

70

65

* Pipe length (ft) specified for maximum pipe lengths located in unconditioned spaces. Pipes located in unconditioned space cannot exceed total allowable pipe length as specified in Table 7.

† Insulation thickness based on R value of 3.5 per in.

A

32oF MINIMUM INSTALLED

AMBIENT OR FREEZE

PROTECTION REQUIRED

A96128

Fig. 43—Rooftop Termination (Dimension “A” is

Touching or 2–in. Maximum Separation)

Fig. 42—Freeze Protection

A93058

An external trap is not required when connecting the field drain to this condensate trap.

The field drain connection (condensate trap or drain tube coupling) is sized for l/2-in. CPVC, 1/2-in. PVC, or 5/8-in. ID tube connection.

Drain pipe and fittings must conform to ANSI standards and

ASTM D1785, D2466 or D2846. CPVC or PVC cement must conform to ASTM D2564 or F493. Primer must conform to ASTM

F656. In Canada, use CSA or ULC listed schedule 40 CPVC or

PVC drain pipe, fittings, and cement.

33

When a condensate pump is required, select a pump which is approved for condensing furnace applications. To avoid condensate spillage, select a pump with an overflow switch.

Furnace condensate is mildly acidic, typically in the pH range of

3.2 to 4.5. Due to corrosive nature of this condensate, a condensate pH neutralizing filter may be desired. Check with local authorities to determine if a pH neutralizer is required.

APPLICATION

The furnace, A/C, and humidifier drains may be combined and drained together. The A/C drain must have an external, fieldsupplied trap prior to the furnace drain connection. All drain connections (furnace, A/C, or humidifier) must be terminated into an open or vented drain as close to the respective equipment as possible to prevent siphoning of the equipment’s drain.