Ford 3500 intake heater amp draw

[joecdeere]

FYI, I just looked in my owners manual for my 345c, which is just an industrial 3930, fuse panel shows a 15amp fuse for the Thermostart circuit

 

[City Farmer]

Thanks for all the help guys. I hope have this tractor wrapped up this weekend. I'll post some pictures when it's finally done.

 

[Soundguy]

Have one of those on my JCB, a push button starter switch should handle the amps, although you should have a "relay" to handle the amperage to the thermostart from the switch, a relay of 40 amps should be fine, in cold weather, you can keep it "activated" for a good 20 seconds (this is where your battery will loose some drain ) and keep it activated while you start your machine. A 20 amp fuse should be good, but if you find it blows, just upgrade to a 30. The length of time you use it will determine the fuse size.

They are NOT glow plugs...

 

[skyhook]

They are NOT glow plugs...

I never said they were.

 

[Soundguy]

I never said they were.

you are giving instructions that apply to a glow plug, but not so much for the ford thermostart.

the ford thermostart ignites a small amount of fuel using a small element. the burning fuel provides the heat.

don't need a high current starter switch, don't need a 40 amp relay, don't need to worry about the battery 'loosing some drain' as you said, and you don't need to keep it engaged during starting because it is not a glow plug.. and if it's blowing a 20 amp fuse, then he has a wiring SHORT. you don't just stick in a higher fuse. Fuses are there to protect the wiring. a 30a fuse on that ignition wire will make smoke!

So while you didn't expressly say glow plugs, your info 100% applied to glow plugs, and not the much different thermostart system ford uses.

 

[City Farmer]

Quick update. I used a 20amp water proof push button starter switch fused at 15amps. The tractor sat for for a day at 40 degrees. I turned on the ignition, pushed/held in the button, hit the key and she fired right up.

 

[skyhook]

you are giving instructions that apply to a glow plug, but not so much for the ford thermostart.

the ford thermostart ignites a small amount of fuel using a small element. the burning fuel provides the heat.

don't need a high current starter switch, don't need a 40 amp relay, don't need to worry about the battery 'loosing some drain' as you said, and you don't need to keep it engaged during starting because it is not a glow plug.. and if it's blowing a 20 amp fuse, then he has a wiring SHORT. you don't just stick in a higher fuse. Fuses are there to protect the wiring. a 30a fuse on that ignition wire will make smoke!

So while you didn't expressly say glow plugs, your info 100% applied to glow plugs, and not the much different thermostart system ford uses.

I understand what your saying, but,....here's my thoughts, like I said, I also have a "thermostart" on my machine. The ignition switch tag burnt do to "overheating" which in turn burned the 15 amp fuse. No more "heat" in cold weather starting. Soooo, I re-wired the thermostart to a "starter button" type switch that has a higher amp rating than a toggle switch. The switch is connected to one of those small square relays, not a solenoid, the high amps go through the 40amp relay to the thermostart controlled by the relay via the low side of the relay. In our part of the country, -30 Celsius is a common thing in the winter, keeping the thermostart on for "30" seconds is common ( try keeping your cigarette lighter on for that amount of time) believe me, it does remove power from the battery, leaving the thermostart in the "on" position while turning over your engine "draws" the heat and lit fuel into the chambers for a better start, letting go of the switch will cause the thermostart to shut off, hence, no more burning hot fuel while cranking. It works well for me, anyways.

Quick update. I used a 20amp water proof push button starter switch fused at 15amps. The tractor sat for for a day at 40 degrees. I turned on the ignition, pushed/held in the button, hit the key and she fired right up.

Tractor sitting for a day at 40 degrees isn't really a test to me, but I'm glad it worked out well "this" time for ya.:thumbsup:

 

[City Farmer]

I agree that 40*F is no real test of a tractor starting but this tractor started hard @50*. I follow exactly what your saying about the relay. Your not the least bit concerned about sending 40 amps to an igniter thats only rated for 15-20?

We'll have to wait until next winter to see if it starts.

 

[Soundguy]

I understand what your saying, but,....here's my thoughts, like I said, I also have a "thermostart" on my machine. The ignition switch tag burnt do to "overheating" which in turn burned the 15 amp fuse. No more "heat" in cold weather starting. Soooo, I re-wired the thermostart to a "starter button" type switch that has a higher amp rating than a toggle switch. The switch is connected to one of those small square relays, not a solenoid, the high amps go through the 40amp relay to the thermostart controlled by the relay via the low side of the relay. In our part of the country, -30 Celsius is a common thing in the winter, keeping the thermostart on for "30" seconds is common ( try keeping your cigarette lighter on for that amount of time) believe me, it does remove power from the battery, leaving the thermostart in the "on" position while turning over your engine "draws" the heat and lit fuel into the chambers for a better start, letting go of the switch will cause the thermostart to shut off, hence, no more burning hot fuel while cranking. It works well for me, anyways.


Tractor sitting for a day at 40 degrees isn't really a test to me, but I'm glad it worked out well "this" time for ya.:thumbsup:

Um yes, I agree you don't know the difference in a high current and low current need circuit.