Fuel Heater Thermostat installed!

warp2diesel · **Posted:** Mon Sep 22, 2008 8:43 pm

Since I live in North Eastern Illinois, I don't want to totally disable my fuel heater for the (-20f) winter coming, but do not want it running when the weather is warm.
In fact, I installed a fuel cooler.
The self regulating heater theory to me is nothing more than Bean Counter Automotive Engineer BS stretched beyond reality. Yes resistance drops along with the wattage, but why heat when it is hot outside?
I looked at and bought several pop button thermostats, but could not find one in an acceptable range. Then I remembered that there is a thermostat on heater tapes used to prevent water line freeze up. The on and off temperatures of 38f on and 50f off sounded not perfect but OK and workable. I bought the shortest 6' heater tape for $16 and salvaged the thermostat.
Here is the link with photos: http://picasaweb.google.com/warp2diesel ... #slideshow

Next, I will tie in a control valve to bypass the fuel cooler that will also be controlled by the thermostat. :idea:

05infernoCRDL · **Posted:** Mon Sep 22, 2008 10:58 pm

i have questions and possibly some suggestions....

why did you loop the end back on its self?
when that thermostat is below 50* it allows wattage through right?
why did you wire it into the ground and not the power?

this is what i am thinking now about what you did and there is a good
chance i am waaaay off......

if you wired it into the power side you could have left the one end that you
looped around go to the 3 way valve and when it got cool enough it should
switch to the fuel heater right?

warp2diesel · **Posted:** Tue Sep 23, 2008 7:09 am

05infernoCRDL wrote:

i have questions and possibly some suggestions....

why did you loop the end back on its self?
when that thermostat is below 50* it allows wattage through right?
why did you wire it into the ground and not the power?

this is what i am thinking now about what you did and there is a good
chance i am waaaay off......

if you wired it into the power side you could have left the one end that you
looped around go to the 3 way valve and when it got cool enough it should
switch to the fuel heater right?

The other side is the 120 V neutral pass through for the heater tape, having both wires coming out the same end means less to seal and allows it to be placed like a probe as it was placed.

The thermostat comes on at 38f and shuts off at 50f. Some engine heat will radiate from the radiator and shut it off when the temp is not cold enough to keep it on all the time.

The ground that was switched was to the relay coil, not the heater power ground. This way I can operate a simple regular solenoid valve that allows the fuel to short circuit the fuel cooler instead of paying the big bucks for a three way valve and using up the under hood real estate. Also, the coil power up side of the fuel heater relay has two wires landed on the terminal and would be more difficult to solder due to having wires going in two directions.

danoid · **Posted:** Wed Sep 24, 2008 1:48 pm

I did a much more manual system.

I removed the mini ISO relay for the fuel heater, pulled off the cover, and ripped out the armature. Then I replaced the cover and painted the top of it red.

If it gets real cold, I replace the dummy relay with a fully functioning one.

Also works for the viscous heater.

warp2diesel · **Posted:** Wed Sep 24, 2008 5:49 pm

Besides the last thing I want to do when I load up at the Airport at 10:30PM and -20f is open the hood and swap relays.
One reason I gave up the old Jetta Turbo Diesel (pre TDI) is that I got tired of proving how good a mechanic I was by having to fix it in the Airport garage at night when I got back using a 6 D cell LED flashlight. I kept the flashlight, traded the 73 Chevy with the Perkins Turbo Diesel on the CRD and sold the Jetta on Craig's list.

BTW: I lived in Oxford, MI up the road from 1965 to 1971, then I left to go to MSU.

Fuel Heater Thermostat installed!

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