Mechanical for Oil Heat Oil Tanks

Oil Tanks

The oil supply system Fuel oil must be supplied to the burner pump as a clean liquid and at the correct pressure for combustion. This supply system consists of: The Oil tank The Piping system

Oil Piping Protective Sleeve

The oil supply system Two basic types of oil storage systems are used: The central storage tank with supply tanks. The supply tank as the only tank.

Central Storage Tank The central storage system is used when one system includes a number of furnaces or boilers. Apartments Commercial factories

Underground Central storage tanks

Above ground Central Storage Tank

Steel Tank sizes This type of system may have an auxiliary oil pump to lift the oil to the supply tank from the storage tank. Residential Steel oil tanks have capacities ranging from 120 to 1,050 gallons. The most common size is 275 gallon.

275 Gallon Steel Fuel Oil Tank

Tank location Oil tanks can be installed: Underground Above ground (outside or inside)

Steel Tank Wall Thickness The tank must be made of 12 gauge metal for an indoor tank. The tank must be made of 10 gauge metal for an outdoor or underground tank. Underground tanks must also have a protective coating on them. Usually they are covered with tar.

Underground Tanks It is customary to bury an underground oil tank 2’ below the surface to prevent damage from surface digging. Strict guidelines must be followed regarding local codes.

Underground Tanks The tank is positioned in the hole on a slight slant, facing away from the oil pickup connection. The slant allows any water or sludge in the tank to drain to the far end of the tank.

Fuel Oil Storage Tank Types Steel Fiberglass Combined Tanks

Steel Storage Tank The mainstay of the industry. They have proven themselves over decades of use and are the most common for aboveground as well as underground installation.

Steel Storage Tank

Fiberglass Storage Tank These tanks are gaining in popularity and have recently passed the UL®™ fire test and can now be installed aboveground.

Fiberglass Storage Tank

Combined Tanks Popular for decades in Europe and passed by UL® for use in the States as well, these tanks combine a plastic tank and a steel tank. The plastic tank serves as an inside liner for storing the fuel, and an outside steel jacket protects this.

Combined Storage Tank

Fill Piping In Connecticut, the fill pipe must be at least 2” diameter wrought iron or steel pipe. The fill pipe should have a slight pitch towards the tank. The fill pipe requires a removable cap.

Vent Pipe The tank must have a vent to allow air to escape as the fuel oil is added. The vent must be 1 ¼” pipe and often has a whistle that sounds when oil is added to the tank.

Vent Pipe The whistle is activated from air escapes the tank as the fuel is added. When the whistling stops, the oil delivery truck knows to shut off the fuel. The tank is now full.

Vent Whistle                                                                   

Indoor Tanks Tank must be on a noncombustible material. There must be a UL approved gauge installed which indicates the amount of oil left in the tank. The fill line must have a cap to protect it from water.

Indoor Tanks Tank outlet must have a fire valve on it, usually a Firematic valve that melts at 165 degrees. The outlet flange on older style tanks is a 1/2” pipe from bottom of tank. This prevents water and sludge to build up and tank eventually needs cleaning.

Firematic ® valve

Supply Piping The outlet on newer style tanks is a 1/2” pipe which is on one side of the tank near the bottom. The tank is pitched 1” towards the valve and this prevents buildup of sludge and condensation.

Supply Piping Supply lines can no longer run under the floor and they must have a plastic or rubber case. Copper corrodes when it is contact with cement. .

Tank Legs The standard leg length is 14” If tank legs are longer than 16” they must have supports

Tank Piping A six inch loop at both the burner and the tank is required for flexibility. Return line (if a two pipe system) must be six inches off the bottom of tank. Supply line (if not from side) must be three inches from bottom of tank.

Above Ground Outdoor Tanks Mainly used if there is no basement, also used in mobile homes. Must be mounted on a masonry foundation for stability.

Above Ground outdoor Storage Tank Come with some operational problems: Cold Climates prevent oil from flowing easily and also allow condensation to build up in the tanks. The colder the temp. the thicker the oil will become. (Viscosity)

Above Ground outdoor Storage Tank May need to install a nozzle line heater. May need to raise the pump pressure. May need to install filter at the appliance instead of at the tank.

Life expectency- underground tanks A common life expectancy of buried oil tanks is 10-15 years. At about 20 years, the risk of leaks from buried steel oil tanks becomes significant. Even if you think the tank is ok, young, and not leaking, buried oil tanks, should be tested for water in the tank bottom. Water should be pumped out since it corrodes the tank and will eventually lead to leaks.

In New England for a two year period among customers who have buried heating oil tanks (16% of total customers) surveyors found an average of 1.7 tank leaks per thousand customers. Also found 2.5 fuel line leaks per 1000 customers.

Indoor oil tanks can easily stay in good condition for 60 years or more. A wide variation in indoor above ground and outdoor above ground oil tank life is due to the considerable variation in both the quality and thickness of oil tank steel.

Oil Tank Seeping at welds

Rotted Oil Tank

Oil Tank Barbecue Pits