Put A Lid On Water Ingression, Says TankDepot.co.uk

Photograph of Heating Oil Tank Fill Area
Put A Lid On Water Ingression Says TankDepot.co.uk's Steve Beech

Oil and water don’t mix and that’s especially true with heating oil, writes TankDepot.co.uk Director Steve Beech.

Each and every winter, thousands of UK heating oil users are left out in the cold, when water makes its way into their heating oil supply. The result is not just a cold house, but frequently an expensive boiler engineer’s bill, that can often be avoided.

In most instances, water forms within the oil storage tank as a result of condensation forming as the tank heats up during the day and cools down during the evening. On a daily basis, the amount of condensation forming inside the tank is negligible. However, over the course of a year, several litres of water can easily accumulate inside.

Understanding this and recognising too that water is heavier than heating oil, plastic oil tank manufacturers position the outlet above the floor of the tank – to minimise the risk of water entering the oil supply line. Metal tanks make allowances for water too. Frequently, they will either have an inbuilt sump, or will be installed at a slight angle, to encourage water to settle as far away from the outlet as possible. Assuming the tank is serviced annually by an OFTEC Registered Technician, or a similarly competent person who checks for the presence of residual water and arranges its removal, both approaches readily suffice.

However, if the tank is not inspected annually and instead, condensate is simply left to accumulate, problems will almost certainly follow. At some point, condensate will enter the oil supply line until sufficient water accumulates to prevent the boiler from firing. In extreme circumstances, water may even freeze inside the oil supply line, effectively isolating the supply of fuel to the boiler. Worse, when the frozen water thaws, the oil supply line may well be split, causing a significant pollution incident.

That’s why as a responsible heating oil tank supplier, we recommend heating oil tanks are inspected as part of the annual boiler service.

But even heating oil tanks which are inspected annually can still be at risk from water ingress due to inattention and sometimes, carelessness. We spoke recently with a gentleman who experienced this first hand last winter. After dipping his tank to see how much fuel remained inside, he forgot to replace the inspection cap. Several weeks and a £140 bill later, he realised his error when his boiler promptly stopped firing, due to enough water having accumulated inside the tank to enter the oil supply line and prevent the boiler from firing.

But even when caps are fitted, the worst excesses of the British weather can wreak havoc with even the best maintained tanks. Hairline cracks can sometimes develop on inspection and fill point caps which allows water to drip into the tank. Mechanical frost action can also damage seals and gaskets which are frequently fitted to secure vents, electronic gauge glands and fill points. And vent caps can sometimes become damaged or go missing… we’ve even seen a photograph of an oil tank vent cover, found in a bird’s nest.

So before the worst of the winter weather sets in, it’s worth spending a few minutes getting up close and personal with your tank to ensure it’s not just weatherproof, but winterproof too. Check all caps and lids are secure. Take a quick look at seals, gaskets and vents to ensure they are present and correct. And if they’re not… replacements are generally readily available, cost a fraction of an engineer’s call out charge and can be fitted in minutes, with no specialist expertise or tools required.

And of course, if you haven’t already done so, remember to book your boiler and tank service too!

Related News