M109 115v Converter and the Fuel Fired Heater

[Wildchild467]

I have been working quite a bit on my M109A3 lately. It used to have a ground fault issue when i pluged it into land power but i got that fixed. the problem was one of the wires on the over head lights was frayed, so i fixed it and it works great now. It would only blow the GFI (located in the garage) when i turned on the light switch, but everything worked. Just stating that incase anybody else has that issue. Well now i cant get the converter to operate the fuel fired heater. everything from the main disconnect works fine to the converter. the converter light comes on when i flip the switch to 115 power (instead of 24 volt) and the little red light comes on. The Heater works fine on 24 volt, but will not work on 115 volt. The part that DOES work on 115 volt is the fuel pump pulling fuel from the tank, supplying the heater and the fan inside the heater works as well. Exhaust fan also works. the part that does not work on 115 volt is the solenoid that clicks metering the fuel... and also not sure if the ignition coil works on 115 volt (but maybe it does as the 115v lights dim when i try to start the heater indicating come current draw, so maybe it does). I have had the heater working, blowing good heat on 24 volt and i quick switch it over to 115 volt and the solenoid that meaters the fuel stops clicking and the heater blower fan speeds up some (probably due to higher voltage the converter puts out vs. the cold 24v batteries).

long story short i looked at the wire drawings and cant seem to pin point why everything else works on 115 volt, but just not the fuel metering solenoid on the heater. any ideas?

 

[slotman]

first can you use a volt meter to see if the solenoid is geting 115 power? could be in the switch same with ignition coil just a starting point.

 

[Wildchild467]

its tough to get in there with a meter... i can try though. i think the 24 volts is getting to the heater switch because everything works great on 24 volt.... but then everything on the heater works (fuel pump and fan) on 115 volt except the fuel metering valve... i dont understand it. i have studied the wiring diagrams, but it still does not make sence why it acts like that.

 

[Wildchild467]

unless there is an interlock somehow?

 

[seabeeut]

I have a brand new unit here I have been rethinking about using.
So your question has me loooking it over my fuel pump and heater are marked 24volt
and the wiring plate shows 110volts to a transformer and bridge rectifier that powers the unit.
The instructions reference a converter box and they have about eight jumpers that need to be in place. Iam confused about the converter box??
I could scan the page with the jumper #'s and placement if you dont already have them?

 

[Wildchild467]

yes, i am talking about the transformer also. im not a 100% sure why i can get the heater working just fine with the switch on 24 volts, but soon as i flip the switch to 115 volts, it runs everything except the fuel metering falve on the heater. i found an additional problem last night, seperate of this one, the high/low switch is not working and only works on high. i need to find the TMs to show the wiring diagrams for the whole box so i can try to make sence of it. maybe my problem is a bad switch somehow if my other high/low switch is not working right.... the other switches cant be far behind if they are corroded some how.