Junkers boiler does not light the burners: Effective solutions.


When the Junkers heater does not light the burners, this can be due to one of several causes. Let’s take a look in this article at what may be happening if the Junkers heater does not light the burners, and what are the most effective ways to repair this fault. You can also consult us forJunkers spare parts.

Why the Junkers heater does not light burners

As we said before, if the Junkers heater does not light the burners, this can be due to several causes. Let’s examine them one by one, as well as the most effective ways to solve them.

The ignition membrane is damaged

If your Junkers heater does not light the burners and it is a pass-through model, it could be the membrane of the automatic ignition mechanism. This membrane can harden, or even perforate. The solution is almost always to replace it. The good thing is that it is not expensive. But, yes, the work must be done by a technician.


When the Junkers heater does not light the burners because the membrane is damaged, it can manifest itself in this way: you open a tap or the shower, and the burner lights up fine. Then you close the tap or shower, and when you open it again the burner does not light unless you open more taps. Typically, it does not turn on if you only use the shower.

This happens because, with higher water flow or pressure, the membrane can work even if it is defective. If your heater is a pilot model, the pilot may light even if the burner does not light.


Manual reset klixon is locked

Some Junkers heater models come with a manual reset klixon (a kind of circuit breaker). In this case, the piece will include a notable colored button in its center. Sometimes that klixon jumps when a certain parameter is altered, and then when the parameter returns to normal, you have to manually reset the button, or else the Junkers heater won’t light the burners.

It can also be the case that the klixon itself is damaged and jumps without cause. To manually reset the klixon, or to replace it with a spare if that is the case, you must contact a technician.


The thermocouple is dirty or damaged

The thermocouple fulfills the function of taking the gas to the pilot, as well as detecting the presence or absence of flame in the burner. If your thermo-sensitive tip is dirty or damaged, or if the gas for some reason does not reach the pilot, the burner will not be able to light. Sometimes with good maintenance or cleaning of the thermocouple and the pilot, everything is fixed. But sometimes it’s time to replace the thermocouple. Best to have this done by a qualified technician.


Dirty, clogged or wrong diameter nozzle

The nozzle or nozzles (also called jets or injectors) fulfill

the function of regulating the flow of gas that passes to the burner to cause the flame. They can be dirty or clogged, and that is one of the cases where the Junkers heater does not light the burners.

The solution for this is cleaning and maintenance of the nozzle or nozzles, depending on the heater model. But it can also happen that the nozzle you use is not the right one for your type of gas.


The nozzle for butane has a specific diameter, and the same is true for propane and natural gas. When the Junkers heater does not light the burners, it is best to contact a technician and, if applicable, install the appropriate nozzles for the type of gas used by your equipment.

Faults in any ignition component

There are several components involved in the heater burner ignition process. If any of them fail, the burner will not light. Some components of the ignition are the electrodes, the transformer, or even the electronic board of the control unit.

Sometimes it’s just that one of these components needs a good cleaning or maintenance. But sometimes you have to replace it with a good spare part.



Junkers HydroPower Heater Problems

This article is perfectly applicable for when any model of Junkers heater will not turn on, including the Junkers HydroPower heater. However, on the reasons why the Junkers HydroPower heater does not turn on, we have written a complete article, to which we refer you: Junkers HydroPower heater does not turn on.

Acquire Junker’s spare parts for your business at Suner

If the Junkers heater does not light, especially when the Junkers heater does not light the burners, sometimes replacement parts need to be installed. Count on Suner to acquire all the Junkers spare parts that your business needs.

We also put at your disposal a wide and well-stocked catalog of spare parts for boilers, burners, and heaters from countless leading brands in the heating market.

Junkers spare parts

Choose Suner as a supplier of spare parts for your business, and we guarantee an uninterrupted supply of original parts of the highest quality and durability. We have fast shipments and after-sales service that adapts to any business model.

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