CenCon
53
Appendix B - Maxitrol Valve Adjustments
The ES345D-L has a built in regulator for high fire. For M and MR series, adjust high fire with the upstream
main regulator.
On DJ style burners, the top of the valve is piped into the burner box to provide a pressure to the top of the
control valve regulator, extending its operating range and overcoming pressure differences due to the varying
combustion blower speed. This is called Top Loading. When setting combustion on a top loaded valve,
temporarily plug the small vent holes when the cover cap is removed to allow top loading to function during
setup. Remove plug once setup is complete, and reinstall the cap cover.
Valve
Model
Adjustment
Top View
Gas Flow
M420
M520
M620
Low fire adjustment.
Vent hole (plug if top loaded)
Low fire bypass (bottom side of valve)
White plastic disk covering
plunger, black side up.
MR410
MR510
MR610
M411
M511
M611
ES433
Low fire adjustment
Vent hole (plug if top loaded)
Vent orifice
Brass disk covering plunger,
black side up.
ES345D-L
MR212
Vent orifice, or top
loading connection
High fire regulator
Low fire adjustment.
Vent hole (plug if top loaded)
White plastic disk covering
plunger, black side up.
Low fire bypass adjustment.
Low fire bypass adjustment.