Manual
4 EH-M3-40 Boiler Operation and Installation Instructions
Table 1. Lug Sizes
Table 2. Flow Switch Size Selection
* Straight pipe upstream and downstream of flow switch.
Model No.
Flow Switch
McDonnell & Miller No.
Pipe
Size
Minimum
Pipe Length*
EH-8-M3 thru EH-20-M3 FS4-3T3-1 1" 6-1/2”
Distribution Block
Grounding Lug
Neutral Lug
Wire Size Wire Size Wire Size
Model Phase CU-AL† CU-AL† CU-AL†
EH-8 thru 20 1 6-2/0 6-2/0 6-2/0
EH-12 thru 20 3 6-2/0 6-2/0 6-2/0
Neutral Lug Wire Size:For 3-wire single phase and 4-wire 3 phase
models equipped with circuit breakers. The neutral tap is for the
circulator and control transformer.
† ALUMINUM conductors may be used, lug size, conduit size, ampacity and all
applicable codes permitting.
Table 3. Current Ratings
† Leg with the highest value of line current of an unbalanced 3-phase load.
‡ 125 VAC maximum rating of all hot conductors.
SINGLE PHASE 3 WIRE, 120/208V
‡
Basic Model
No.
Heater Amperes
@ 208V
EH8-13-8-M3
EH10-13-8-M3
EH12-13-8-M3
EH16-13-8-M3
EH20-13-8-M3
29
36
43.4
58
72
SINGLE PHASE 3 WIRE, 120/240V
‡
Basic Model
No.
Heater Amperes
@ 240V
EH8-13-4-M3
EH10-13-4-M3
EH12-13-4-M3
EH16-13-4-M3
EH20-13-4-M3
33
42
50
67
83
THREE PHASE 4 WIRE, 120/208V
WYE CIRCUIT ONLY
‡
Basic Model
No.
Heater Amperes †
@ 208V
–
–
EH12-34-8-M3
EH16-34-8-M3
EH20-34-8-M3
–
–
43
58
†
72
†
THREE PHASE 4 WIRE, 120/240V
DELTA CIRCUIT ONLY
‡
Basic Model
No.
Heater Amperes †
@ 240V
–
–
EH12-34-4-M3
EH16-34-4-M3
EH20-34-4-M3
–
–
50
67
†
83
†