Building an Inline Glowplug Heater

[bruceT Senior Member Find all posts View Profile Close bruceT]

I have a 26 plate, flat plate heat exchanger before my fuel filter. However, the temp drops considerably after the filter and then again after the Pollak valve. To improve my changeover times and provide a heating boost just before the IP, I want to install an inline heater.

I would like to make my own glowplug inline heater to provide this boost. Does anyone have any plans or instructions for building these? They look simple enough, but I need some help with the thermostat control of it.

[Captain Echidna Senior Member Find all posts View Profile Close Captain Echidna]

Re: Building an Inline Glowplug Heater

you could use a thermo fan switch, which often has a temperature probe and a control box. If it doesent have switch contacts that operate the right way (normally a fan will turn on when things are hot, you will want it to turn off when things are hot) you could use a relay that switches between two contacts so when the relay is "on" the contacts are "off"

[bruceT Senior Member Find all posts View Profile Close bruceT]

Re: Building an Inline Glowplug Heater

I had thought of using a thermoswitch Chris, but thought (wrongly) that because the thermoswitch turns ON when it reaches temp, that it would have to be one that turns OFF when it reaches temp. As you can deduce, electronics is out of my area. Maybe there is one that turns OFF when it reaches temp, that would eliminate the relay? Would some sort of overload protection also be needed?

Those items are reasonably easy to get hold of, so I'll work on that idea and ask a mate to help out with the wiring. If it works, I'll post a "How to for Dummies"!

[Captain Echidna Senior Member Find all posts View Profile Close Captain Echidna]

Re: Building an Inline Glowplug Heater

I would recomend a fuse of some sort (near the power source) in case anything goes wrong. I dont know how much current a glow plug requires, but if you work it out, the fuse/ cable requirements should be larger. (if the glow plug draws 10 amps, then use a 15 amp fuse and cable. Dont use a 15 amp fuse and 10 amp cable, or things may not go well)

If you can get one that turns off at the temperature, you are in luck, the only problem may be that a glow plug draws more current than the switch can handle. An easy (but "agricultural") way to go about it would be.
Find out what the temp switch is rated to.
use a fuse of that rating.
If it blows the fuse, then turn on a horn/ heavy duty relay with the temp switch, and use heavier cable (say 20 amp) a 20 amp fuse.

[Guest Close David]

Re: Building an Inline Glowplug Heater

Maybe there is one that turns OFF when it reaches temp, that would eliminate the relay? !

Try this: http://www.jaycar.com.au/productView...SPECIAL=&form=
KEYWORD&ProdCodeOnly=&Keyword1=&Keyword2=&pageNumb er=&priceMin=&priceMax=&SUBCATID=

This is a simple thermo switch that will switch a load ON till it reaches 100o and then off till the temp drops back to 85. There is also a 90/75 rating available.

You will have to use a relay with these devices just in the normal configuration of switching the heavy current loads. A 30 Amp relay should easily handle a glowplug or 2. Rather than use a fuse, for the princely sum of 7 bucks you can use a resettable circuit breaker which are vastly superiour to a one shot Fuse.

In addition to a circuit Breaker, you may also want to wire in a thermal fuse if something goes wrong and your oil gets too hot. These are also available from Jaycar in a range of heat settings, the 132oC or 157oC being the most likely ones for the application.

Make sure you wire the relay through a supply switched through the ignition so the heater isn't trying to work when the car is not being used.

[bruceT Senior Member Find all posts View Profile Close bruceT]

Re: Building an Inline Glowplug Heater

This info is most helpful and much appreciated. Thanks guys!!