Trane Gas Unit Heaters カタログ
12
UH-PRC002-EN
Application Considerations
Venting Unit Heaters
Venting unit heaters and duct furnaces used to be as simple as remembering that warm air rises.
With the introduction of new venting equipment and safety controls, things have become a little
more technical. Today’s contractor has to know a lot more about proper venting to get the job done
within code at a reasonable price.
With the introduction of new venting equipment and safety controls, things have become a little
more technical. Today’s contractor has to know a lot more about proper venting to get the job done
within code at a reasonable price.
For starters, ANSI now categorizes vented appliances into four categories. Category I includes non-
condensing appliances with negative vent pressure, like the traditional atmospheric unit heater.
Category II groups condensing appliances with negative vent pressure.
condensing appliances with negative vent pressure, like the traditional atmospheric unit heater.
Category II groups condensing appliances with negative vent pressure.
Category III appliances are non-condensing and operate with a positive vent pressure, like the
traditional power vented unit heater. Category IV covers condensing appliances with positive vent
pressure.
traditional power vented unit heater. Category IV covers condensing appliances with positive vent
pressure.
Sharing Flues with Other Appliances
Never connect power vented devices to common flues. Mechanically vented appliances must have
dedicated vents to the point of termination.
dedicated vents to the point of termination.
Power Vented Unit Heaters
Mechanically vented appliances have enjoyed increasing acceptance in American facilities. Power
vented unit heaters allow installation without the need to penetrate expensive roofing materials.
They also offer more flexibility in placement of individual unit heaters.
vented unit heaters allow installation without the need to penetrate expensive roofing materials.
They also offer more flexibility in placement of individual unit heaters.
Table 1.
Orifice chart: Rockwell 043–182 regulator
Inlet Pressure
(psi)
Capacity in Mbh for Natural Gas
Spring Required
25–200 225–300 350–500 600
700
800
1
3/8”
—
—
—
—
—
Blue (only)
2
3/8”
3/8”
—
—
—
—
Blue (only)
3
3/8”
3/8”
3/8”
—
—
—
Blue or Green
5
3/8”
3/8”
3/8”
3/8”
3/8”
3/8”
Blue or Green
10
3/8”
3/8”
3/8”
3/8”
3/8”
3/8”
Blue or Green
20
1/4”
1/4”
1/4”
1/4”
1/4”
5/16”
Blue or Green
40
1/4”
1/4”
1/4”
1/4”
1/4”
1/4”
Blue or Green
60
1/8”
1/8”
1/8”
1/8”
1/8”
3/16”
Blue or Green
80
1/8”
1/8”
1/8”
1/8”
1/8”
—
Blue or Green
100
1/8”
1/8”
1/8”
1/8”
1/8”
1/8”
Blue or Green
125
1/8”
1/8”
1/8”
1/8”
1/8”
1/8”
Blue or Green
Venting Categories
Non-Condensing
Condensing
Negative Vent Pressure
I
II
Positive Vent Pressure
III
IV