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7800 SERIES EC7890A,B/RM7890A,B RELAY MODULE
65-0204–1
3
Table 1B. EC7890 Terminal Ratings.
1
The EC7890 must have an earth ground providing a connection between the subbase and the control panel or the equipment.
The earth ground wire must be capable of conducting the current to blow the 20A fuse (or breaker) in event of an internal short
circuit. The EC7890 needs a low impedance ground connection to the equipment frame which, in turn, needs a low impedance
connection to earth ground. For a ground path to be low impedance at RF frequencies, the connection must be made with
minimum length conductors having maximum surface areas. Wide straps or brackets rather than leadwires are preferred. Be
careful to verify that mechanically tightened joints along the ground path, such as pipe or conduit threads or surfaces held
together with fasteners, are free of nonconductive coatings and are protected against mating surface corrosion.
2
Range of allowable operating frequencies is 45 to 66 Hz.
3
2000 VA maximum connected load to 7890 Assembly.
Environmental Ratings:
Ambient Temperature:
Operating: -40
°
F to 140
°
F.
Storage: -60
°
F to 150
°
F.
Humidity: 85% RH continuous, noncondensing.
Vibration: 0.5G environment.
Dimensions:
Refer to Fig. 1 and 2.
Weight:
7890 with dust cover: 1 pound 13 ounces, unpacked.
IMPORTANT
Flame Detection System available for use with the
7890. To select your Plug-in Flame Signal Amplifier
and applicable Flame Detector, see Table 2 and
Fig. 3-5.
Terminal No.
Description
Ratings
G
Flame Sensor Ground
Earth G
Earth Ground
1
L2(N)
Line Voltage Common
3
Line Voltage Supply (L1)
200 Vac (+10/-15%), 50 or 60 Hz (+/- 10%).
2,3
4
Alarm
200 Vac, 1A pilot duty.
5
Unused
6
Burner Controller and Limits
200 Vac.
7
Unused
8
Pilot Valve/Ignition
200 Vac, 4A at PF = 0.5, 20A inrush.
9
Main Fuel Valve
200 Vac, 4A at PF = 0.5, 20A inrush.
10
Ignition
200 Vac, 4A at PF = 0.5, 20A inrush.
F(11)
Flame Sensor
60 to 220 Vac, current limited.
12
Unused
13
Unused
14
Unused
15
Unused
16
Unused
17
Unused
18
Unused
19
Unused
20
Unused
21
Unused
22
Shutter
200 Vac, 0.5A (EC7890B).