User Guide

6 EH-M2-40 Boiler Operation and Installation Instructions
Table 1. Lug Sizes
Table 3. Current Ratings
Table 2. Flow Switch Size Selection
† Leg with the highest value of line current of an unbalanced 3-phase load.
‡ 125 VAC maximum rating of all hot conductors.
Model Phase
Distribution
Block Wire Size
CU
Ground Lug
Wire Size
CU
Neutral Din
Rail Mount
CU
EH-40-M2
EH-8-M2 thru 32-M2
EH-12-M2 thru 40-M2
1
1
3
2-3/0 MCM CU
6-2/0
6-2/0
6-2/0
6-2/0
6-2/0
14 Min.
14 Min.
14 Min.
The neutral tap is for the circulator and control transformer.
† Aluminum conductors may be used, lug size, conduit size, ampacity and all applicable codes permit-
ting. However, aluminum conductors may not be used for models over 32kw.
Model
Flow Switch
McDonnell
& Miller No.
Pipe
Size
Pipe Length
of Flow
Switch**
EH-40-M2
EH-8-M2 thru 32-M2
FS8W
FS4-3T3-1
1-1/4"
1"
8-1/2"
6-1/2"
SINGLE PHASE 3 WIRE, 120/208V
‡
Basic Model
No.
Heater Amperes
@ 208V
EH8-13-5-M2
EH10-13-5-M2
EH12-13-5-M2
EH16-13-5-M2
EH20-13-5-M2
EH24-13-5-M2
EH28-13-5-M2
EH32-13-5-M2
EH40-13-5-M2
29
36
43.4
58
72
87
101
116
145
SINGLE PHASE 3 WIRE, 120/240V
‡
Basic Model
No.
Heater Amperes
@ 240V
EH8-13-5-M2
EH10-13-5-M2
EH12-13-5-M2
EH16-13-5-M2
EH20-13-5-M2
EH24-13-5-M2
EH28-13-5-M2
EH32-13-5-M2
EH40-13-5-M2
33
42
50
67
83
100
117
133
167
THREE PHASE 4 WIRE, 120/208V
WYE CIRCUIT ONLY
‡
Basic Model
No.
Heater Amperes †
@ 208V
–
–
EH12-34-5-M2
EH16-34-5-M2
EH20-34-5-M2
EH24-34-5-M2
EH28-34-5-M2
EH32-34-5-M2
EH40-34-5-M2
–
–
43
58 †
72 †
69 †
69 †
83 †
108 †
THREE PHASE 4 WIRE, 120/240V
DELTA CIRCUIT ONLY
‡
Basic Model
No.
Heater Amperes †
@ 240V
–
–
EH12-34-5-M2
EH16-34-5-M2
EH20-34-5-M2
EH24-34-5-M2
EH28-34-5-M2
EH32-34-5-M2
EH40-34-5-M2
–
–
50
67 †
83 †
79 †
79 †
96 †
125 †
** Straight pipe upstream and downstream.