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Rheostat Switch For Universal Heater

electrical

Best Answer jonsharman , 31 March 2020 - 08:29 AM

I am assuming you are replacing the existing heater with the Universal type from Mini Spares?

 

The Rheostat is the same as a switch just with a resistor to limit the flow of current thus speeding the motor up or down.  Behind your existing heater you will have two wires - a Light Green / Orange and a Black with bullet connectors on them.  The light green / orange wire provides the +12v ('hot wire' as referenced above) to the input side of the switch on the heater.  A green / yellow wire comes off the output side of the switch to the motor and the black completes the circuit from the motor to the ground.  When you close the switch current can flow from the light green / orange wire through to the green / yellow wire into the motor and then back out to ground thus completing the circuit.

 

To install the universal heather I would disconnect the existing heater leaving just the light green / orange and black wires at their bullet connectors near the bulkhead.  Take a feed from the light green / orange into the input side (+ve) of the rheostat, take a feed from the output side of the rheostat to the input (+ve) side of your universal heater and finally feed from the (-ve) side of your heater back to the black wire.  Getting the polarity (+ve and -ve) the right way round is important so the motor spins in the right direction and should be either labelled on the heater itself or in the instructions.  It is sensible to make sure the wire you use has a suitable current rating for the heater and rheostat and an in-line blade fuse is never a bad idea to add another level of protection.

 

Hope that helps.

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#1 BJPclassicmini

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Posted 30 March 2020 - 11:17 PM

Hi there,

I am installing the aftermarket universal heater attached below.
I am a newbie to wiring and I am looking for guidance as to how to wire in a lucas rheostat switch to the heater? 

http://www.minispare...|Back to search


It has a black ground wire and a red wire. wondering where i should join each one to. watched one video where it says "find a hot source" (american video) for the red wire.

As i'm not an electrician i need a bit more help than that.

Many thanks!
Ben. 



#2 jonsharman

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Posted 31 March 2020 - 08:29 AM   Best Answer

I am assuming you are replacing the existing heater with the Universal type from Mini Spares?

 

The Rheostat is the same as a switch just with a resistor to limit the flow of current thus speeding the motor up or down.  Behind your existing heater you will have two wires - a Light Green / Orange and a Black with bullet connectors on them.  The light green / orange wire provides the +12v ('hot wire' as referenced above) to the input side of the switch on the heater.  A green / yellow wire comes off the output side of the switch to the motor and the black completes the circuit from the motor to the ground.  When you close the switch current can flow from the light green / orange wire through to the green / yellow wire into the motor and then back out to ground thus completing the circuit.

 

To install the universal heather I would disconnect the existing heater leaving just the light green / orange and black wires at their bullet connectors near the bulkhead.  Take a feed from the light green / orange into the input side (+ve) of the rheostat, take a feed from the output side of the rheostat to the input (+ve) side of your universal heater and finally feed from the (-ve) side of your heater back to the black wire.  Getting the polarity (+ve and -ve) the right way round is important so the motor spins in the right direction and should be either labelled on the heater itself or in the instructions.  It is sensible to make sure the wire you use has a suitable current rating for the heater and rheostat and an in-line blade fuse is never a bad idea to add another level of protection.

 

Hope that helps.



#3 Ethel

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Posted 31 March 2020 - 09:16 PM

As an alternative you could look for a pwm motor speed controller on the likes of Ebay.

 

It'd be more efficient and not generate as much  heat, some of the cheaper ones might whine a bit though.



#4 BJPclassicmini

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Posted 01 April 2020 - 09:41 PM

I am assuming you are replacing the existing heater with the Universal type from Mini Spares?

 

The Rheostat is the same as a switch just with a resistor to limit the flow of current thus speeding the motor up or down.  Behind your existing heater you will have two wires - a Light Green / Orange and a Black with bullet connectors on them.  The light green / orange wire provides the +12v ('hot wire' as referenced above) to the input side of the switch on the heater.  A green / yellow wire comes off the output side of the switch to the motor and the black completes the circuit from the motor to the ground.  When you close the switch current can flow from the light green / orange wire through to the green / yellow wire into the motor and then back out to ground thus completing the circuit.

 

To install the universal heather I would disconnect the existing heater leaving just the light green / orange and black wires at their bullet connectors near the bulkhead.  Take a feed from the light green / orange into the input side (+ve) of the rheostat, take a feed from the output side of the rheostat to the input (+ve) side of your universal heater and finally feed from the (-ve) side of your heater back to the black wire.  Getting the polarity (+ve and -ve) the right way round is important so the motor spins in the right direction and should be either labelled on the heater itself or in the instructions.  It is sensible to make sure the wire you use has a suitable current rating for the heater and rheostat and an in-line blade fuse is never a bad idea to add another level of protection.

 

Hope that helps.


Thanks a lot for the detailed help! Will follow it to the T.

Cheers!







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