111368-04 - 1/22
Series 49
WARNING
This boiler must only be installed, serviced, and repaired by a qualified installer, service agency or gas
supplier. Improper installation, adjustment, alteration, service or maintenance can cause severe personal
injury, death, or substantial property damage. For assistance or additional information, consult a qualified
installer, service agency or gas supplier. Read these instruction carefully before installing.
!
Installation, Operating and Service Instructions for
Manual Contents Page
1. Qualified Installer, Service Agency or Gas Supplier
Read Before Proceeding . . . . . . . . . . . . . . . . . . . . . .3
2. User/Homeowner Read Before Proceeding . . . . . . .4
3. Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
4. Locating Boiler . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10
5. Preparing Boiler . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14
6. Venting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15
7. Steam Piping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18
8. Gas Piping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22
9. Electrical . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24
10. System Start-Up and Checkout . . . . . . . . . . . . . . . .31
11. Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .39
12. Before Leaving Jobsite . . . . . . . . . . . . . . . . . . . . . . .40
13. Service and Maintenance . . . . . . . . . . . . . . . . . . . . .41
14. How it Works . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .45
15. Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . .49
16. Service Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .56
Appendix A Steam Boiler Skimming . . . . . . . . . . . . . . .71
Appendix B Indirect Water Heater . . . . . . . . . . . . . . . . .72
Appendix C McDonnell & Miller 150S-MD Auto Reset
LWCO/Pump Control . . . . . . . . . . . . . . . . . . . . . . . . . . . .74
WARNING
Attention Installer -
Affix these instructions
adjacent to boiler. Provide model number and
serial number when seeking information and
support.
Attention Building Owner -
Retain these
instructions for future reference. Contact a
qualified installer, service agency or gas
supplier for all issues and support.
!
• Steam Boiler
• Cast Iron
• Chimney Vent
• Gas Fired
NOTICE:
Knock-Down Boilers: These instructions
address installation and controls. Assembly is
addressed in separate instructions shipped with
knock-down boilers.
Models:
•
49-075S
•
49-100S
•
49-125S
•
49-150S
•
49-175S
•
49-200S
•
49-250S
•
49-299S
•
49-350S
•
49-399S
•
49-450S
•
49-500S
•
49-550S
VELOCITY LOGO CMYK COLORS
