Truma S5002 Gas Heater

May 8, 2021
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I am having trouble lighting my heater! I have fitted a new battery in the ignition unit, and cleaned the battery contacts, but no ignition, and I cant hear any clicking. I spoke to a caravan dealer, who said that the ignition units can pack up, OK, but a new one is over £80 !! Any suggestions? I have "toyed" with the idea of fitting an alternative means of ignition, or even a manual piezo.

It is also difficult to see how you are supposed to get at the burner to service the pilot, and Truma seem very reluctant to supply any information. I used to be CORGI registered, so I do know my way round gas appliances, if someone could point me in the right direction please!

Any help or suggestions would be very welcome!

Richard D.
 
Jun 16, 2020
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If you Google low volt spark ignition or generator, there are plenty. If it were me, I would have a go at wiring one of those in. After all, a spark is just a spark. I think to wire one in would be easier than fitting a manual one as part of your wiring already exists.

John
 
May 2, 2020
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Hi welcome to the forum
With regards to the spark generator I think you will have 2 plugs 1 goes to the electrode to ignite gas single wire , the other has 2 wires that comes from the control dial, if you remove the unit from fire and short the 2 pins from the dial on the unit with a screwdriver you should hear a clicking noise, if not you need to replace unit. DONT get fingers near the single outlet (could be shocking)
 
Oct 3, 2013
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If you Google low volt spark ignition or generator, there are plenty. If it were me, I would have a go at wiring one of those in. After all, a spark is just a spark. I think to wire one in would be easier than fitting a manual one as part of your wiring already exists.

John
Be aware,the high voltage output from the spark generator should be the same as what is fitted. If the output voltage is higher then you have to check the insulation value of the wiring and the device that produces the spark , that it matches or exceeds the output voltage of the spark generator.
 
Jun 16, 2020
1,270
405
935
Be aware, the high voltage output from the spark generator should be the same as what is fitted. If the output voltage is higher then you have to check the insulation value of the wiring and the device that produces the spark , that it matches or exceeds the output voltage of the spark generator.
Sorry. don't agree. The voltage produced is sufficient to cause a spark. The gap is fairly consistent across appliances. the voltage may well be many thousands, but there is no reason for the physics to differ.

John
 
Mar 14, 2005
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The ignitor fitted to the 5002 is a " Re-ignitor". Its controlled by a microswitch in the gas valve assembly , and the switch act on the negative side of the battery, and one wire of the pair to the switch is deliberately grounded under a clamp to provide the return path for the spark energy. It also provides a connection for an internal high impedance resistive flame detection circuit which inhibits the generator when a flame is present. This acts on one burner.

The flame detection circuit only controls the spark generator, the main flame failure cut out is a thermocouple on the other burner that powers a solenoid in the gas control valve.

The set up requires the flame to establish on the sparks burner, there is a flash over tube between the exchange tubes which should almost immediately light the second burner so the flame failure thermocouple is heated.

As for spark potential, I'm not recommending or suggesting using a higher voltage unit, but the maximum voltage of the generator achieves will be determined by the size of the spark gap at the burner. A speak generator with a higher discharge capacity cold compromise teh PTFE insulation on teh spark electrode.

Its best to stick with the designed component which is a quick and simple fix.
 
Jun 16, 2020
1,270
405
935
The ignitor fitted to the 5002 is a " Re-ignitor". Its controlled by a microswitch in the gas valve assembly , and the switch act on the negative side of the battery, and one wire of the pair to the switch is deliberately grounded under a clamp to provide the return path for the spark energy. It also provides a connection for an internal high impedance resistive flame detection circuit which inhibits the generator when a flame is present. This acts on one burner.

The flame detection circuit only controls the spark generator, the main flame failure cut out is a thermocouple on the other burner that powers a solenoid in the gas control valve.

The set up requires the flame to establish on the sparks burner, there is a flash over tube between the exchange tubes which should almost immediately light the second burner so the flame failure thermocouple is heated.

As for spark potential, I'm not recommending or suggesting using a higher voltage unit, but the maximum voltage of the generator achieves will be determined by the size of the spark gap at the burner. A speak generator with a higher discharge capacity cold compromise teh PTFE insulation on teh spark electrode.

Its best to stick with the designed component which is a quick and simple fix.
I was responding to the OP suggesting that the fault is with the spark generator. A simple device. But it appears that it is auto ignition. A different kettle of fish.

John
 

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