KAH Operation & Maintenance Guide
Page: 31 of 88
Krueger | 1401 N Plano Rd | Richardson, TX 75081 | 972.680.9136 | [email protected] | www.krueger-hvac.com
CFM
TEMPERATURE RISE (°F)
INTERNAL
PRESSURE
DROP WC
DF- 175
DF- 200
17,000
95
--
0.45
18,000
90
--
0.52
19,000
85
--
0.57
20,000
81
93
0.63
21,000
77
88
0.7
22,000
74
85
0.76
23,000
71
81
0.82
24,000
68
78
0.9
26,000
62
71
1.05
28,000
58
66
1.25
30,000
54
62
1.4
32,000
51
58
1.6
34,000
48
54
1.8
35,635
45.5
52
2
DF- 225
DF- 250
DF- 275
DF- 300
24,000
87
--
--
--
0.337
27,000
77
86
92.5
--
0.427
30,000
69
77
83.3
90.8
0.527
33,000
63
70
75.8
82.5
0.637
36,000
58
64
69.5
75.7
0.758
39,000
53
59
64
70
0.89
42,000
50
55
59.5
65
1.035
45,000
46
51
55.6
60.6
1.185
48,000
43
48
52.1
55.8
1.35
51,000
41
45
50
53.5
1.525
54,000
39
43
47
50.5
1.71
58,475
35
39.5
43.5
47.5
2
DF- 325
DF- 350
DF- 375
DF- 400
31,565
95
--
--
--
0.4
35,290
85
92
--
--
0.5
41,755
72
78
83
89
0.7
47,345
64
68
73
78
0.9
52,340
57
62
66
71
1.1
54,665
55
59
64
68
1.2
59,045
51
55
59
63
1.4
63,125
48
51
55
59
1.6
66,950
45
48
52
55
1.8
70,573
42.6
45.9
49.2
52.4
2
TABLE 7 - BURNER TEMPERATURE RISE (CONT’D)
SECTION 2 - START-UP & OPERATION (CONTINUED)
WARNING -
Rotating parts and electrical shock
hazards exist. Lock out and tag out the fan motor(s)
and heat power disconnects before servicing.
Use the latest lock out/tag out procedure. Failure
to follow proper safety precautions may result in
serious injury or death.
Application Information
1. Follow the procedure given in this instruction to find
the minimum air velocity for safe operation (see Figure
1). At least this minimum velocity must be provided at
all points over the heater face area. Failure to meet
this requirement may result in serious damage or
nuisance thermal cutout tripping.
2. The maximum air inlet temperature for open coil
heaters is 100°F, and for finned tubular heaters, 80°F.
3. Sufficient working space must be provided per
paragraph 110-26 of the NEC.
4. This electric heater is not designed for or intended to
be used for temporary heat prior to system startup /
balancing.
Mechanical Installation
1. All heaters will contain an adjustable airflow switch
in the heater control panel. This switch will be preset
to close at a differential pressure of approximately
0.3” W.C. In all cases the switch will be connected to
a pressure probe positioned in the air stream. This
probe has an arrow stamped on it that is viewable from
inside of the control panel. When the heater is located
upstream of the fan this arrow will point away from the
fan. When the heater is located on the downstream
side of the fan the arrow will again point away from the
fan or with airflow. If it is incorrectly installed, remove
the (2) screws holding the pressure probe in place and
rotate 180° and reinstall. The airflow switch pressure
port that is not connected to this pressure probe will
be run to the exterior of the air handling unit to source
a reference differential pressure. In some situations it
may be necessary to adjust this airflow switch setting
to allow for proper operation. Precautions must be
made at this time to make sure that the airflow switch
does not provide a false indication of airflow. Failure to
meet this requirement may result in serious damage or
nuisance thermal cutout tripping.
2. A visual inspection of the heater elements should be
made prior to use of the heater. If physical damage is
evident, a Megohm test should be used to validate the
heater elements are safe for use. If a minimum value
of 10 megohms is not achieved then any damaged
elements or ceramic insulators must be replaced
prior to operation.
