# Interest group forums > Food Industry Forum > [Question] Chip Fryer Maintenance

## AmithS

Hi Everyone,

was just wondering, what type of maintenance do you carry out on your chip fryers on a daily and weekly basis.

I am looking at oil filtering process and machine cleaning process.

When do you filter your oil ? When its cold in the morning or hot in the evening before closing ?

Thanks,

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## AndyD

Chip fryers are very simple devices so there's relatively few things that can go wrong. Most of the problems that do occur are caused by the operator being reckless or negligent or ill-trained.

*The trailing supply cable* is prone to physical damage. Straining the cable beyond its natural length when moving the fryer for cleaning behind can cause problems such as broken glands and split cable sheath, this can result in an enormous flash/bang if the insulation is completely breached. The same is true if the fryer is pushed too hard against the wall behind it causing the cable to be crushed at the entry point and breaking the gland. This type of damage can be prevented by having stand-offs at the back of the fryer to stop it short of the back wall and by having a chain that is the correct length to prevent the cable being strained. To compound the cable problem the oil attacks and degrades the cable and any other plastic components over time. The supply cable should not be PVC construction, rather a HO7RNF type neoprene trailing cable which is somewhat more oil and heat resistant. Budget to replace the cable every two years.

*Elements* should last for many years. The most common problem is staff switching the fryer on and the tank being empty. Because of the high heat density of fryer element tubes they don't last long in fresh air unless they're particularly good quality. Elements of this high quality are very few and far between in SA, the purchase price is prohibitive. Similar problems can occur if the fryer oil level isn't topped up throughout the day to compensate for oil absorbed by the food.
Using oil that's solid at room temperature can reduce element life or cause failure if it's not packed properly around the elements when the fryer is filled from cold.
Fryers with removable elements can be prone to cable damage when the elements are extracted for cleaning purposes and not supported.
Finally certain frying such as calamari where there's very large quantities of flour left in the oil can cause element burnout if the residual flour in the bottom of the fryer tank is allowed to build up past the level of the elements and it hinders the convective circulation of the oil past the elements during the heating process.

*Thermostats* are prone to damage by ingress of oil and/or steam especially in the low priced badly designed fryers. They're also prone to blunt force trauma causing damage from the front; again the likelihood of this can be minimized by good design. The thermostat sensing bulb which sits in the oil tank and its associated capillary tube can be easily damaged by over zealous cleaning procedures. Once again good design can mostly prevent this. A fryer should have two thermostats, one is adjustable to achieve the correct oil temperature, the other is mounted iinternally and acts as a safety device to prevent overheating and spontaneous oil flash fires. I'll come back to this below.
Thermostats are commonly the mechanical variety but you also get fryers with digital thermostats and even PID controllers. I'm not personally sold on the idea of digital devices in this kind of operating environment but I do understand the prolonged oil life that can be achieved might make it a worthwhile trade-off.

*Contactors* are the devices which switch the power to the elements. They make a crisp clean _clack_ sound every time they switch on or off. You can often tell that a contactor is distressed or failing contactor just by the sound it makes. Common causes of contactor failure include poorly made electrical connections, ingress of oil and overheating. Overheating can be caused firstly the contactor being sandwiched hard against other components such as the circuit breakers or another contactor which reduces the airflow around it. Secondly it can also be caused by poor design resulting in the electrical enclosure having a high ambient temperature because of its proximity to the hot oil tank or poor insulation around it. Contactors can also be damaged as a result of elements blowing and causing a large enough fault current to flow through them to burn the contacts.

*Indicator lamps* are common victims of physical damage, plastic degradation by oil and heat damage. They will require regular replacement.

Other common causes of damage are;

Bashing the baskets on the body of the fryer to supposedly drain the oil from the food quicker after frying.Allowing oil to boil over during frying which invariably ends up getting in the electrical enclosure. High oil levels or high water content in food can cause this.Water-logging electrical components during cleaning.

Always keep the fryer lids in the kitchen in close proximity to the fryers. If there's a fire these are your best chance of extinguishing it quickly.

Check the operation of safety thermostats and other safety devices regularly.

In SA the safety codes for fryers are primitive compared the the EU and US. Their legislation insists on fryers being built with a safety thermostat and a safety contactor which can isolate the power to the elements if dangerously high temperatures occur. In this country you will only usually find one control contactor and no safety contactor in the cheaper fryers. The lack of the fail-safe contactor makes them far more prone to fires. Contactors regularly fail in the closed position and when this happens the risk of fire is very high.

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flaker (28-Nov-10)

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## AndyD

> When do you filter your oil ? When its cold in the morning or hot in the evening before closing ?


This would depend on the quantity and type of frying you're doing. 

There are filtering machines which can hot filter such as Bitterling which I heard are no longer manufactured. These machines are expensive and few and far between in SA. I'm not sure if it's preferable to filter hot at night or cold in the morning.

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## AmithS

Hi AndyD,

Thanks for that very comprehensive explanation above.  All the information is much appreciated.

Thanks,

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## AmithS

Im trying to find out if there is something i am doing wrong here!

I clean out the fryer where i make fish every night (drain & filter oil, clean and put oil back)

The problem i am having is that the small batter pieces left in the fryer, block the stop cork and makes it very difficult to drain?

Any one with some advice?

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