Have been working on a monarch burner and have been having some trouble with the operation of the servo drive - there is adjustable cams on it and so far I understand 4 of them. this is a 3 stage burner on a grain dryer and the cams 1-6 control air and fuel trigger points- The burner starts on 2 jets until it reaches it's set point in the plenum chamber then cuts back to 1 jet- for this too happen the servo needs to operate and turn about 12 degrees to reduce the combustion air and turn off the 2nd jet- this is where the problem has occurred servo doesn't want to return- as I don't know what cam controls this part- I know the cam that turns the second jet on/off but unsure how to set it to react with the thermostat
the servo cams are 1- 2- 3-sets air for medium fire (2 jets) 4-low air setting-this seems to control only the amount of air when the burner shutting down 5- 6- trigger for 3rd jet to operate ( the third jet is activated by a manual switch which triggers the 2nd and 3rd jet to work together (winter)
As you can see I"m short on info any help from someone who has worked on these before would be great