Marine Cooker Servicing

Follow one of our engineers as he checks and repairs a Plastimo Neptune 2000 cooker in for a winter service.

Hover your mouse over each picture for a description of what is illustrated.

The life of a cooker can often be extended by simple servicing work and by the replacement of any corroded or worn parts. This Plastimo Neptune cooker was made in March of 1995. It has seen good service, but its owner had noticed during the last season that the hotplate burners and the grill had been burning with a yellow flame. This not only has made the saucepans black, but unknown to its owner, it has been producing Carbon Monoxide.

Once the cooker was on my workbench, I suspected the problem to be corrosion, as rust was visible on both hotplate burners and the grill burner. At the point, it was also worth checking the common problem areas. On the Neptune 2000, one of the commonest areas for rust is the oven flue, in the top of the oven at the rear. On this cooker it looked worse than it was, there is still a few more years service left in it yet. The rest of the cooker looked OK.

The first job was to remove the front facia, so I could get to the grill burner. I pulled off all four the control knobs and then undid the locking nuts. It is worth noting that on later models there is no locking nut on the Oven control. The front facia could now be pulled off revealing the control valves and the grill burner. I undid the top screws and the locking nut that held the thermocouple into the control valve. I could then remove the complete grill burner. After undoing the hexagonal spacers, I removed the grill burner from the reflector and fret assembly. On closer examining, I could see how badly the burner was corroded. After running a wire brush over the reflector, I replaced the burner and hexagonal spacers. I fitted a new thermocouple for good measure and replace the whole assembly back in the cooker. I was careful to locate the end of the grill burner over the jet holder. I tighten the new thermocouple finger tight and then 1/8 of a turn with a spanner. Once back in place and the top screws replaced I tested the burner. The flame looked clear and stable.

Next I turn my attention to Hotplate. The Hotplate burner should lift off once the grub screw has been undone. On this cooker, some gentle persuasion was needed as they were badly corroded. Once I had removed burner cap the cause of the problem was plan to see. The Cast Iron of the burner cap had been rusting away and the flakes of rust had filled the top of the burner base. This had stopped the burner operating correctly and hence the yellow flames.

I removed the rust and cleaned the burner base, and then using a small file, I gently smoothed the top edge of the burner base removing any remaining corrosion. This was important, as any corrosion left here would stop the flame from sitting correctly around the new burner cap. Once the burner cap had been replaced, I tested the burner to see if it had the correct flame picture and it sat properly on the burner. It is also important that the flame makes contact with the thermocouple that operates the Flame Supervision Device (FSD). It all looked fine and the burner stayed alight.

I then looked at the oven. The oven flue had flakes of rust and loose debris, I removed these as they could have fallen in to food as it was being cooked. Next I checked the burner. The flame picture looked fine so there was no work extra needed. I left the oven on with the gas thermostat turn about ¾ of the way round. This was to test the effectiveness of the thermostat and to check that once the oven had come to temperature, the flame cut down. All was fine. I carried out a visual inspection of the oven door and seal. I also checked the effectiveness of the door seal trapping a piece of paper in the door and feeling the resistance when I pulled it out. It felt fine to me. If it was loose, then by repositioning and tightening the screws on the door hinge, I could adjust the door position.

As the markings on the facia had worn, I replaced the facia with a new one. After refitting the facia, I also replaced the control knobs with new ones for cosmetic reasons.

The armoured hose fitted to the cooker had caused me some concern when it was brought in, the owner had asked me to replace it. I also replace the compression fitting connecting the hose to the cooker. With all the work done, it was time to do the final tests on the cooker.

I lit each burner in turn recording the time it took for the FSD to hold. The rules say that this should happen within 20 seconds, however 5 – 10 seconds is normal. Then I turned the flame out and recorded the time for the FSD to drop out. The rules say this should happen within 90 seconds for the hob and grill burner, but 30 – 60 seconds would be normal and 60 seconds for the oven, but 20 – 45 seconds is usual.

The last thing to check was the gas soundness of the cooker using a water gauge. Once I had completed the test report, the cooker was ready for collection.

Cost of replacement parts:

2 x Burner Caps
1 x Grill burner tube
1 x Set of Hexagonal spacers
1 x Grill thermocouple
1 x Facia
4 x Control Knobs
1 x Compression Coupling
1 x Armoured hose

Labour Cost (30 minutes)

The total cost of the parts came to £100, which is a quarter the cost of a new one. These parts should extend the life of the cooker another 5 years. The only part of the cooker that caused me any concern was the corrosion around the oven flue. The first sign of a problem here will be the flue gases escaping into the grill compartment. This in itself is not dangerous, however it could cause problems with the grill and hotplate burners staying alight, as the composition of the air around the burners will be wrong, it having a higher concentration of Carbon Dioxide. It may also lead to a re-circulation of combustion gases causing vitiation producing Carbon Monoxide.

As the main service centre for Plastimo Cookers on the South Coast, Southampton Calor Gas Centre keeps an extensive range of spare parts, as well as having workshop facilities. Cookers can be serviced on site; spares sold over the counter or sent mail order.

For further details please contact Southampton Calor Gas Centre on 0800 917 8188