With drought’s having been declared and hosepipe bans in place in parts of England earlier this summer, the prolonged periods of dry weather we experienced now seem but a distant memory. And as we head into winter, now’s the time we hear about people getting water in their oil fired central heating oil tanks. So, here we’re taking a look at how to identify when you have water inside your oil tank, what to do to remove it and dispose of it safely and how to avoid it in the first place.
It’s virtually impossible to detect water in your tank from an external tank inspection. Water doesn’t mix with oil and is heavier, so any water that has found it’s way into your heating oil tank will sink to the bottom, meaning it can’t be seen when you peer into your tank. This makes it difficult to remove. Often, the first sign of water contamination in your tank can be when your oil central heating boiler that’s fed from your tank, or your range cooker if you have one, starts playing up. It’s important to stress that if your heating oil tank does have water it in, then it should be removed at the earliest opportunity before it causes damage. Keep reading for our expert advice.
How does water get into a heating oil tank?
Often, people assume that water has got in to their tank with the domestic heating oil they’ve had delivered - a common misconception that the delivered fuel is in fact contaminated. In truth, there are two ways that water can get into your oil central heating tank, the first being rainwater ingress. This could be due to a split or hole in the tank, an ill-fitting filler cap, corroded seals, a damaged vent, a split in the tank itself or even by simply leaving the lid off.
The second way that water can get into your tank is through a build-up of condensation. Whilst rain water can trickle in to any open gaps entering the vent pipe, it’s more likely that condensation is to blame. Condensation is more common during the spring and summer months when as the weather starts to warm up, your heating oil tank's internal temperature is cooler than the outside temperature. Moist air cools down inside the tank and causes water vapour to form water droplets which will eventually settle on the bottom of the tank as water is denser than most fuels. Central heating oil tanks in direct sunlight are especially prone to this. Over time the accumulated water can cause corrosion of the tank, frozen fuel lines, and damage to your central heating boiler.
Over time, a layer of water can build up at the bottom of your tank along with a sludge build-up of black particles in the oil. When you receive your delivery of heating oil, this can stir up the oil and sludge with the water, which can then disturb the flow of oil through your pipework and into your boiler affecting performance.
Worth mentioning, our Premium Heating Oil, specially formulated to make your boiler run at its best, helps reduce the amount of sludge that builds up in your tank over time, and also contains corrosion inhibitors which help stop rust, and metal deactivators that reduce fuel degradation.
How to prevent water in your oil tank
Prevention of water contamination in the first place is always the favourable option. Taking preventative measures to avoid troublesome problems by properly maintaining your heating oil tank and regularly testing your home heating oil can help you avoid the hassle and costs associated with fuel contamination. So here are some useful tips for reducing the potential of rainwater getting in to your central heating oil tank:
- Regularly inspect your tank and pipework yourself, checking for signs of cracks, corrosion and other physical damage. Look out for oil stains on the tank and pipework and ensure there are no signs of leaks on the area around the tank
- Check your oil tank for bulging. This can indicate weaknesses in the exterior walls
- Ensure lids and caps are secure
- Keep topped up. Leaving your heating oil level low leaves room for air which increases the risk of humidity and condensation occurring inside the tank
- If your tank is bunded, make sure the bund is in good condition and could hold an oil spill. Make sure the bund is not full of water
- Cut back any over-hanging trees or foliage, and remove any leaves or garden water from around your tank and/or in the case of a bunded tank, in the bund itself
- Have your tank inspected annually by an OFTEC registered oil heating engineer as part of your boiler service. Your engineer will ensure your tank is in a good condition and in the best possible state to stand up to adverse weather conditions as we head into winter.
Could my oil tank have water inside?
To detect whether water is present at the bottom of your tank, a water finding paste can be used. Use a dipstick or rod (a clean garden cane is ideal) that is long enough to reach the bottom of your tank. Smear the paste onto the end and lower into the tank, making sure it reaches the bottom. The paste will then react with any water that may be present. Leave it upright (usually for around 30 seconds), and if there is water present at the bottom of the tank, the paste will change colour.
How do I remove water contamination?
So you’ve detected water in your oil fired central heating tank! The important thing is to get rid of it as soon as you possibly can before it gets into your boiler and causes any damage. Over a long period of time, the water level in your tank can build up sufficiently to enter the fuel line, which will cause damage to burner components, affect combustion or could freeze in winter months, blocking the oil tank outlet or even the fuel supply.
Older metal tanks often have a sludge (or run-off) valve at the bottom of the tank. This can be used to drain off the water into a container, as water settles at the bottom of the tank. The container should then be sealed and stored until the waste is disposed of, so it doesn’t spill anywhere. Plastic tanks don’t have this facility, but small amounts of water can be siphoned off with a hand pump.
For small amounts of water, there’s the option of a highly absorbent tank dryer, which is a water filtration device that removes any water. It sinks into place at the bottom of the heating oil tank and has a cord attached. When fully swollen it should be removed and discarded responsibly. Also available are simple and easy to use water absorbent tank sponges, which are polymer filled socks, with a recovery string for easy retrieval.
For larger quantities of water, i.e. more than an inch or two, or if you have an underground tank, we would recommend you get in touch with an OFTEC registered oil heating engineer to get the water removed from your tank. They will also be able to advise you on how to prevent water getting into your tank in future, or whether, in the case of cracks or splits, you may in fact need a new tank.
What will happen if I leave the water in my tank?
In time, leaving the water in your tank will cause corrosion which can lead to more problems such as leaks which can have environmental impacts, or result in a decline in your oil central heating system’s efficiency. The rust, water and oil on the bottom of your tank will form a bacteria-ridden sludge that will contaminate your fuel supply. This sludge will corrode the interior of your tank, the fuel lines, burner components and filters.
How to dispose of the contaminated water
However the water is removed, bear in mind it will be contaminated! It’s important to dispose of it safely and responsibly, and most certainly not down the drain! It will need to be taken to a local authority waste disposal site with a waste oil collection tank. And once removed, you may need to flush your boiler feed pipe and potentially replace fuel filters – an OFTEC heating oil registered engineer will be able to do this for you.
We hope you’ve found the information in this blog useful. Keeping a regular eye on your tank is definitely the best way to try and avoid troublesome problems. Remember, we’re always here to help – we’re just a phone call away. If you’d like to speak to us about your heating oil tank concerns, just give us a call on 01423 770 666 or email us at helpoil@northernenergy.co.uk.
For more expert advice from Northern Energy, why not take a look at our tank regulations blog post?