Starting The Electric Heater - York AHU Operation And Maintenance

SECTION 2 - START-UP AND OPERATION
TABLE 9 - BURNER TEMPERATURE RISE (CONT'D)
CFM TEMPERATURE RISE (°F)
DF- DF-
175 200
17,000 95 --
18,000 90 --
19,000 85 --
20,000 81 93
21,000 77 88
22,000 74 85
23,000 71 81
24,000 68 78
26,000 62 71
28,000 58 66
30,000 54 62
32,000 51 58
34,000 48 54
35,635 45.5 52
DF- DF-
225 250
24,000 87 --
27,000 77 86
30,000 69 77
33,000 63 70
36,000 58 64
39,000 53 59
42,000 50 55
45,000 46 51
48,000 43 48
51,000 41 45
54,000 39 43
58,475 35 39.5
DF- DF-
325 350
31,565 95 --
35,290 85 92
41,755 72 78
47,345 64 68
52,340 57 62
54,665 55 59
59,045 51 55
63,125 48 51
66,950 45 48
70,573 42.6 45.9
46
INTERNAL
PRESSURE
DROP WC
0.45
0.52
0.57
0.63
0.7
0.76
0.82
0.9
1.05
1.25
1.4
1.6
1.8
2
DF- DF-
275
300
-- -- 0.337
92.5 -- 0.427
83.3 90.8 0.527
75.8 82.5 0.637
69.5 75.7 0.758
64 70 0.89
59.5 65 1.035
55.6 60.6 1.185
52.1 55.8 1.35
50 53.5 1.525
47 50.5 1.71
43.5 47.5 2
DF- DF-
375
400
-- -- 0.4
-- -- 0.5
83 89 0.7
73 78 0.9
66 71 1.1
64 68 1.2
59 63 1.4
55 59 1.6
52 55 1.8
49.2 52.4 2

Starting the Electric Heater

Rotating parts and electrical shock haz-
ards exist. Lock out and tag out the fan
motor(s) and heat power disconnects be-
fore servicing. FOLLOW THE LATEST
"LOCKOUT TAGOUT" PROCEDURE.
Failure to follow proper safety precau-
tions 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 Fig. 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 se-
rious 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 National Electrical Code
(NEC).
4. This electric heater is not designed for or intend-
ed 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 airstream. 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 two 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 dam-
FORM 102.20-OM2
ISSUE DATE: 6/01/2015
JOHNSON CONTROLS