Product Overview

Dimensions for tankless heater coils must be followed for proper installation and operation.
Problems that may occur include the tankless heater coil not fitting into the boiler or the well for
the aquastat hitting the tankless coil which will not allow for proper temperature sensing. The
charts shown here provide the dimensions that must be followed for proper fit and operation of
tankless heater coils in Weil-McLain boilers. Tankless heater coils supplied by Weil-McLain are
designed to provide proper tankless heater coil installation and operation.
Subject: Proper Tankless Heater Coil and Aquastat Operation
Boiler Heater Part Boiler Heater Part
Model Size Number Number Model Size Number Number
3 – 10 E-624 590-921-904 3 – 7 E-624 590-921-904
E 6 – 10 E-626 590-921-905 62 4 – 7 E-626 590-921-905
6 – 10 E-632 590-921-901 5 – 7 E-632 590-921-901
E Storage 6 - 10 62-2-E 590-921-665 62 Steam 3 – 7 62-S-2 590-921-655
35 – 75 E-624 590-921-904 62 Storage 4 - 7 62-2-E 590-921-665
EG 50A – 75 E-626 590-921-905 3 – 9 E-624 590-921-904
65 – 75 E-632 590-921-901 65 5 – 9 E-626 590-921-905
EG Steam 35 – 75 35-S-29 590-921-903 7 – 9 E-632 590-921-901
EGH 85 – 125 E-626 590-921-905 65 Steam 3 - 9 35-S-29 590-921-903
95- 125 E-632 590-921-901 3 – 9 E-624 590-921-904
EGH Steam 85 – 125 35-S-29 590-921-903 66 5 – 9 E-626 590-921-905
3 – 6 WT-14 590-921-612 7 – 9 E-632 590-921-901
WTGO 3L WT-11 590-921-599 66 Steam 3 – 9 35-S-29 590-921-903
7 – 9 WT-20 590-921-610 3 – 9 E-624 590-921-904
GO Steam 3 – 9 35-S-29 590-921-903 68 5 – 9 E-626 590-921-905
42 4 – 7 E-624 590-921-904 7 – 9 E-632 590-921-901
5 – 7 E-626 590-921-905 68 Steam 3 – 9 35-S-29 590-921-903
42 Storage 6 – 7 62-2-E 590-921-665 76 Stm & Wtr 3 – 9 35-S-29 590-921-903
43 4 – 7 E-624 590-921-904 78 Stm & Wtr 3 – 12 78-34 590-921-917
5 – 7 E-626 590-921-905 88 Stm & Wtr 4 – 18 820 590-921-909
92,94 Stm & Wtr 8 – 25 92-K-34 590-921-910
Heater Dimensions
Heater Maximum Coil Maximum Coil Maximum Heater
Number Diameter Length Width
E-30 (2) 3-1/2” 15” 8-3/4”
E-624 5” 11” 5”
E-626 5” 16” 5”
E-632 5” 19-3/8” 5”
35-S-29 3-1/2” 14-1/2” 7-1/2”
62-2-E 4-1/2” 18-1/2” 4-1/2”
62-S-30 (2) 3-1/2” 18”** 6-3/4”
WT-11 5” 11” 5”
WT-14 5” 14” 5”
WT-20 5” 20” 5”
78-34 3” Lower Coil 21.75” 7”
820 3-1/2” 25” 7-1/2”
92-K-34 4-3/8”* 42” 2-3/8”
* Height of Tubing
** 5 Degree Upward Slope
Number: SB0004-Rev1 (Page 1 of 1)
Date: February 4, 2000 (Rev 03-16-2004)