This problem recurs in my fridge/freezer and I resolve it by taking out the inner panel of the freezer compartment to expose the freezer unit at the back of the freezer. This unit ices up occasionally and becomes a solid block of ice, the result of which is to severely impair the function of the freezer. Defrost until there is no sign of ice between the freezer pipes and fins etc, replace the cover and switch on. In my case with a Beko freezer, this does the trick and it works like new after defrosting.

Grip the blade in a vice, ensuring you have access to one of the key holes in the centre. Place a punch in the hole and tap it round anti-clockwise with a hammer until it loosens.

I’m not familiar with this particular model but all of the similar appliances I have worked on usually have a cover that wraps around on three sides. After removing all of the cover screws, slide the cover towards the rear of the oven for about half an inch. The cover should then lift away from the main body. Hope this works for you.

Check to make sure you don’t have a leak on the intake manifold or the manifold side of the carb’. you can check this by dribbling a little oil along the joint to see if it gets sucked in. If this is the case, then the engine will be sucking in air without the petrol vapour to ignite and so causing a ‘flat spot’.

Obtain a ‘Piston seal’ repair kit and renew the three seals. The water is leaking past the seals and causing a drop in pressure. While it’s apart renew the large ‘O’ ring body seal too.

Further to Mayer's very well informed suggestions, may I add a suggestion of my own? I am not familiar with this type of machine in the UK, but if it has a motor that employs brushes, I should check that the brushes are not worn down, do not have broken or weak springs, and are not sticking in the guides. A new set of brushes can remedy a lot of obscure faults for relatively little cost.

The pressure switch indicated by Mayer can be tested by disconnecting the tube from the tub and gently blowing into it. As the pressure builds a faint click should be heard from the switch unit ,indicating that the switch contacts have been activated. Another faint click will be heard only when you release the pressure. If the switch clicks before you release the pressure, then the diaphragm inside the unit is faulty. Another cause could be a faulty solenoid coil on one of the inlet valves. There are usually two, (hot and cold). Isolate the power from the machine and disconnect the two wires from one of the solenoids. With a multimeter set on a low OHM's range, place the prods one on each terminal of the solenoid. If a reading is obtained, the coil is good. If no reading shows, then the coil is open circuit and a new solenoid valve is required. Hope this is helpful.