GENERAL

The light oil burner, as supplied by Boilersmith Ltd., comes complete with an individual burner oil pump for each burner. The interconnections involving suction line(s), return line(s), and oil tank are field installed.

NOTE Certain sized boiler/burner units are supplied with remote oil pump sets. The pump discharge piping is field installed for these units. /

The proper field installation of the fuel oil piping and fuel oil storage system is most important to the success of any burner operation. If suction piping is not air tight, or if suction and return piping are not properly sized, burner performance will be impaired and not dependable.

Long or oversized inlet lines may require the pump to operate dry during initial bleeding period. In such cases, the priming may be assisted by injecting light oil into the priming tee located at the highest point above the burner.

NOTE Always provide a priming tee and plug in the suction line at the highest possible point to aid in priming the pump and in expelling air. /

Installations putting fuel oil where it is exposed to temperature extremes should be avoided. The pour point limit for No. 1 and No. 2 fuel oils not seasonally adjusted is 0⁰F and 20⁰F, respectively.

AUXILIARY LIGHT OIL PUMP

An auxiliary light oil transfer pump should be used where individual burner pumps are beyond the practical pumping limit. This pump should be located as close as possible to the oil tank and should be sized to circulate twice the maximum oil consumption (preferably through a non-pressurized loop).

NOTE The auxiliary light oil transfer pump should be located as close as possible to the oil storage tank.

The oil transfer pump is used to deliver oil to the individual burner pumps under a slightly positive head through a circulating loop sized for no more than 3 psig pressure drop.

The positive displacement gear-type light oil pump is of such a design that its pump seal will be damaged if the return line pressure exceeds 3 psi.

OIL TANK

The oil tank should be installed in accordance with local, regional and national building codes and standards.

CAUTION Maximum recommended pressure on return side of pump is 3 psig. Consult the pump manufacturer's specification sheet and install in accordance with NATIONAL, REGIONAL and LOCAL Codes and Standards.

CAUTION IF an oil transfer pump is used, the Maximum recommended pressure on the suction side of the pump is 3 psig. Consult the pump manufacturer's specification sheet and install in accordance with NATIONAL, REGIONAL and LOCAL Codes and Standards.

LIGHT OIL PIPING

The individual burner light oil pump is a gear type, which should not pump at a vacuum greater than 10 inches Hg or 10 foot lift from the bottom of the oil storage tank to the.pump plus 100 feet horizontal and vertical run (including equivalent length of pipe for fittings, valves, etc.). Although the pump is capable of developing higher inlet vacuums, excessive vacuum operation should be avoided because of vapour binding, noisy pump operation, and excessive pump wear. Copper tubing should be used in preference to iron pipe, as it requires less work, is neater, has less possibilities of leaks and does not scale off on the inside. For protection from dents and bending, it is desirable to run the tubing in conduit pipe or tile.

FLARE TYPE FITTINGS are recommended, as the soldered type may melt in case of fire.

CAST IRON FITTINGS ARE NOT ALLOWED DO NOT USE COMPRESSION FITTINGS DO NOT USE TEFLON TAPE

Connections to buried tanks must be made with swing joints or copper tubing to prevent the pipes form breaking in case the tank settles. If local requirements stipulate that iron pipe be used, swing joints made up with elbows and nipples several inches long should be used on both the suction and return lines as close to the tank as possible.

The swing joints should be made up so that they will tighten as the tank settles. Non-hardening pipe joint compounds should be used on all threaded joints.

All oil suction piping must be tested for leaks before connection to the individual burner pump. The oil suction line between the pump and suction inlet (closest possible connection at tank) should be pressure tested using air. There should be no noticeable pressure drop over a period of several hours.

An alternate oil suction piping test consists of subjecting the suction line to a vacuum of not less than 20 inches Hg for several hours without a noticeable drop.

OIL PUMP SUCTION AND RETURN LINE SIZING

The size of the oil line suction line is dependent upon the type of oil, amount of lift, length of suction line and suction capacity of the pump.

NOTE The total suction piping loss of a system is the sum of the vertical lift loss and the total pipe length loss (horizontal and vertical). Total pipe length loss is determined by adding the total straight length plus the equivalent straight length values for all other pipe fittings, valves, strainers, filters, etc.

On single pump installations the return line should be the same size as the suction line.

Since most trouble in light oil systems is attributed to leaky oil suction lines, on multiple pump installations each pump should have its own individual suction line.

NOTE Each Pump should have its own individual suction line.

One return line may be used as long as it is "appropriately sized" since all pumps may share a common return line.

Refer to pump manufacturer's bulletins for proper line sizing.

The lines from the tank to the burner should be sized from data contained in the pump manufacturer's specification sheet, but in NO INSTANCE should they be smaller than 1/2" o.d. copper tubing.

Install tank slip fittings in the top of the tank for both the suction and return line connection. Push both suction and return lines down through the fittings until they touch the bottom of the tank and then pull the suction line up three inches and lock in position with a compression nut. Pull the return line up six to seven inches from the bottom of the tank and lock in position with a compression nut.

OIL SHUTOFF VALVE

A hand shutoff valve should be provided in the suction line near the burner.

NOTE Hand valves must not be installed on discharge side of pump or return line without a bypass relief to tank. A check valve is sometimes utilized to prevent oil spillage when it becomes necessary to disconnect the return line at the pump. Do not use globe type valves in the suction line due to excessive pressure drop. Use gate valves to isolate oil accessories.

Fusible Valves (Melt Valves) are available. In the case of an oil tank positioned higher than the burner unit, and should a fire develop, oil could run out and intensify the fire. A fusible valve helps to minimize this risk.

NATIONAL, REGIONAL and LOCAL Codes and Standards may require the use of fusible valves.

CHECK VALVE

Properly installed fuel oil suction lines do not require check valves for proper operation.

However, check valves are often used to compensate for deficiencies in oil line piping.

For example :
a) Not having the return line submerged in the oil in the oil tank.
b) Having vacuum leaks in the line due to using compression fittings, bad flare fittings, porous fittings, loose fittings or leaky lines.

Disadvantages

Check valves increase the amount of vacuum the fuel unit must overcome to supply oil to the system and reduce the distance supply lines can be run.

When installed near the fuel unit, check valves cause turbulence and stripping of air from the oil, resulting in dirty and/or noisy combustion.

Do not use check valves in gravity feed (tank above pump) single- pipe systems, or in system supplied by a boost or transfer pump. Thermal expansion can cause serious problems.

NOTE Select a check valve of the soft seated type suitable for No. 2 oil, which will seat tightly with a low head.

If a check valve must be used and the top of the oil tank is below the burner level, use a lift type check valve with neoprene seat.

STRAINER/FILTER

An oil strainer/filter of adequate capacity must be used.

It is our recommendation that a strainer/filter should not be less than 0.75" npt pipe size.

NOTE The Strainer/Filter should be sized for the total pumping capacity of the oil pump, not the nozzle capacity.

OIL SUCTION LINE

Suction piping should be pitched back to the tank slightly whenever possible and particular care should be taken not to create an air trap in the line. There is always a slight amount of air in suspension in oil, and if air traps are present, they will gradually fill with air, and the pump will lose its prime.

Removal of air is generally very difficult.

NOTE Always provide a priming Tee and plug in the Suction Line at the highest possible point to aid in priming and in expelling air.

See the pump manufacturer's instructions for priming and venting.

A two-pipe system is required for all installations. Both the suction and return piping should be run in a trench under the floor level where possible.

Other than at the oil pump, which generally has a smaller supply and return connection than the recommended piping size, DO NOT install valves, fittings, filters, etc. that have an inside diameter or port size smaller than the inside diameter of the oil suction piping.

Always leave provision on the oil suction line between the filter and oil pump for the installation of a vacuum gauge.

Always leave provision on the return line, near the pump return connection, for the installation of a pressure gauge.

CAUTION Overhead suction lines should be avoided unless an auxiliary oil circulating pump set is used. Maximum standpipe height above the burner pump is 7.5 feet unless special devices are installed to prevent hydraulic shock from causing pump seal leakage.