Hi Jayne,
A lot of the older fridges suffer from fine dust particles blocking the jet, these particles are age related rusting of the gas supply pipe, as damp can creep in via the jet, over long long periods of standstill over winter.
To clean the pipe using a suitable thin wire, is all i do, scraping the inner tube as i wiggle the bare electrical wire and twisting/rotating it to loosen the possible dust crumbs.
the job is simple, but does require confidence in use of posidrive screwdriver and two spanners, also a clean white cloth i suggest to catch the jet as easily (usually) falls out of the heater.
One of the first jobs to do is to remove lower outer cover to reveal the supply and larger element pipes, a red/orange wire to spark igniter, care not to rotate this as the igniter is fixed inside a white ceramic holder that can after age be a little loose.
NOTE: the igniter tip is in the circular heater area, so look at it as you remove the heater, it should be looking upwards.
Also you should see the gas supply pipe fixed by a locking nut to the heater block and thin metal flexible pipe that is the thermostat/temp sensor going to the gas selector valve.
Observe the heater, a square rectangle block, with a large hole through it, physically connected to the round heater element that has 3 upward tongues one having a screw fixing/securing it to the exhaust.
PREPARE YOURSELF
Have 11mm and 13mm open head spanners to undo the locking nut so releasing the gas supply pipe.
Once the outer cover is off, a few parts need to be removed using a posidrive screwdriver.
These parts are plastic water collector, sat on return fluid pipe, and the metal covers surrounding the heater element.
Using same screwdriver remove the heater from the exhaust tube. Note this screw is a threaded screw, not a self tapper which are used to secure the covers. DO NOT LOSE - METRIC THREAD.
I usually have tissue paper under the joint where the locking nut is situated to catch any dust, and the jet if it topples out.
DO NOT PUT PIN INTO JET HOLE.
the jet is round plate approx 9mm width, curved like a bowl, shiny appearance, with a hole in it which you should see through if shining a light the opposite side.
DO NOT ENLARGE, OR CLEAN HOLE with pins, BLOW INTO IT TO REMOVE ANY DUST.
Using a suitable electrical wire or metal rod, insert into gas pipe and twist as you go, angle gas pipe and tap the gas pipe to allow dust to drop out onto tissue paper.
You will not get much possibly but you can see it collected on the tissue.
I can get a single cable (electrical single core type) upto the second bend in the gas pipe and often get an amount of dust out.
If you can get someone to turn the fridge selector on also, you will get some dust blown out to improve the cleaning outcome.
CAREFULLY replace jet so the jet hole is inserted facing the heater, replace gas pipe to secure jet, jet can rotate, so go slowly and observe the position of jet - you will soon find a technique to ensure it fits together.
Hand tighten the locking nut, ensuring the heater is positioned correctly and will fit/attach to the exhaust correctly.
Fully tighten the gas pipe gently.
Replace all parts and test operation of fridge.
You can check flame ignites and heater before refitting by just hanging it out of the cover hole.
Hope that makes sense.
I often do this task and find I sometimes have to do it again as reassembly twists the igniter so it touches the metal heater edge - shorting it out - this is because my ceramic holder has been damaged so does not grip correctly.
Once you have done it once (about 1 hr)
You soon learn how to complete it in 20 minutes.
I did buy a new heater block, and jet some 5/7 yrs ago, but still find I need to clean dust out of the supply pipe. Did it twice on our last trip in Feb.
Honestly it is a simple task, just be confident.
