Comfort Line - Questions and Answers

This quarter our question and answer segment discusses the relationship between outside above ground oil tanks and cold oil problems in the winter.

I’m considering replacing my underground oil tank. What type of replacement tank should I install?

Modern underground tanks last for more than 30 years and are safe for the environment. Unfortunately, there is a perception that they are not safe. Therefore, we recommend replacing your underground tank with an above ground tank. The best, most cost effective replacement tank on the market is the Roth Double Wall Tank. The inner tank is made of blow-molded, seamless polyethylene and the outer tank is made of rust proof galvanized steel. The tank comes in four sizes and can be tied together to increase the storage capacity. Roth tanks come with a leak detection system and a 10-year warranty that includes $1 million of environmental cleanup coverage.

Is it better for above ground tanks to be installed inside?

It’s far better to install a new tank inside rather than outside. This is perfectly safe because heating oil is combustible, not flammable. Combustible liquids will not burn unless they are heated. The temperature at which heating oil will burn, known as the flash point, is 140°F. Flammable liquids, like propane, will burn at room temperature and are unsafe if installed in a home. Since heating oil is more concentrated than other fuels, it is affected by the cold. The pour point of heating oil is 0°F and the cloud point is 10°F. This means that when the outside wind chill is 10°F or less the oil starts to gel and will not flow properly. Over the years many customers with outside tanks have experienced problems keeping their heat on when the weather is extremely cold. Unfortunately, these problems always seem to occur on the coldest day of the year, which makes them even more inconvenient. The best way to avoid this problem is to install the tank inside, if possible. The most common locations are in the basement or the garage.

I have an outside tank. What can I do to prevent cold oil problems?

Hart & Iliff adds a pour point depressant whenever we deliver to an outside tank. This lowers the pour point approximately 5°F and helps to mitigate cold oil problems. Roth tanks are better in the cold than a steel tank because the air space between the outer tank and inner tank insulates the oil like thermal pane glass. However, even with a pour point depressant and a Roth tank, heating oil can still gel when it is very cold. When the oil gels it’s very difficult, even for our trained technician, to keep the heat on. Over the years we tried many different techniques but there was no fool-proof solution until the recent development of a product known as an electric tank heater. This device heats the oil, keeping it warm enough to eliminate the cold oil problem. See the related article for more information about the electric tank heater.