Providing Solutions Today for Tomorrows Bio Fuel Market

Webster®

Fuel Pumps & Valves

M34DM-3 Bio Pump

M34DM-3 Bio PumpFeaturesTo meet the needs of today’s fuel-efficient, downsized and spaceefficient burners, Webster’sM34DM-3 incorporates improvedaccess to both the bleed valve andbypass plug. Locating the bleed portplug assembly on the side of thefuel unit provides the servicetechnician with one visible andaccessible location to either bleedthe fuel unit or change the bypassplug without removing the burner.

In addition to improved access theM34DM-3 cleaner blade has beenthickend to provide a more robustcleaning action. For maximumprotection, an additional line filtershould be used in accordance withrecommended standardpractice All of the BUNA-N elastomershave been replaced withVITON to provide extendedlife at critical locations within thefuel unit.

The M34DM-3 retains all the industryaccepted, state-of-the-art features ofthe M34DK-3 fuel unit. These includefaster fuel cut-off, improved primingon single pipe installations. This unitcan easily replace your standardM34D or A2VA residential pump.

The M34DM-3 is capable ofmaintaining a three gallon per hourfire size at up to 150 PSI throughoutits design life. The M34DM-3 isfactory preset to 100 PSI and isadjustable to 150 PSI.

General Operation and Fuel UnitOil FlowThe compact M34DM-3 Fuel Unit isengineered for efficient pumping ofBio fuel. The cut-away view illustratesthe oil flow through an M34DM-3operating in a one pipe system, witha suction line and no return to thestorage tank.

A one pipe system is frequently usedwhen the storage tank is locatedabove the fuel unit, or whenautomatic venting is not necessary.Vacuum at the pump inlet should notexceed 10” Hg. For this type ofinstallation to be reliable, the totalsystem must be completely airtight.During installation or servicing of thefuel unit, air may be manually bledfrom the system through the side-located bleed valve.

One Pipe SystemFuel enters the fuel unit through theinlet port and is drawn into the frontcover chamber. A vacuum, createdby an inner and outer rotating gearset, pulls oil through the rotary filterand into the gears. As oil movesaround the gears, it is compressed,creating a higher pressure. Oilleaving the gear set branches intotwo paths. One path leads to thepressure regulating chamber. Asecond path directs oil to the bleedvalve. Oil flowing into the pressureregulating chamber branches intotwo paths. Up to three gallons perhour can flow out the nozzle port,and the remaining oil by-passes thepressure regulator, returning to thefront cover chamber.

The M34DM-3 will provide up to10” Hg of inlet vacuum. The twopipe system (shown below), withboth a suction and return line isself-venting. This allows any air inthe system to escape and bereturned to the storage tankthrough the return line.

Two Pipe SystemThe by-pass plug, inserted throughthe bleed valve port, blocks thesurplus oil return to the frontchamber. This oil is directed to thereturn port and back to the storagetank.

For More Information on Bio FuelGo To www.biodiesel.org.

n Fuel subject to vacuum

n Fuel at atomization pressure

n Fuel at return pressure

Specifications

Dimensions

Firing Capacity:Recommended to 3 GPH fire size forpressures from 100 to 150 PSI with#1, #2 fuel oil, Kerosene, or Bio FuelB100-B5 Bio Diesel

Gear Capacity:25 GPH @ 100-150 PSI with #1, #2fuel oil, Kerosene, or Bio Fuel. B100-B5 Bio Diesel.

Pressure:Factory set at 100 PSI.Adjustable to 150 PSI.

Inlet Requirements:10” Hg maximum vacuum (approx.10’ vertical lift - exact distance willvary with tubing diameter and length).3 psig maximum inlet pressure.

Speed:3450 RPM.

Rotation: (As viewed from shaft end):Clockwise (D Style).

Porting:• 1/8” NPTF, side located nozzle port.• 1/8” NPTF, top located gauge port.• 1/4” NPTF, bottom and cover

located inlet ports and bottomlocated return port.

• Bypass plug accessible through theside located bleed port plugassembly.

• 3/8” flow through bleed valve.

Nozzle Location:(As viewed from shaft end):Clockwise (D Style) - Right side.

Shaft:5/16” dia., 1.65” extension frommounting face, with keyless “D” drive.

Filter:Self-cleaning rotary type.

Elastomers:VITON shaft seal.All other seals are VITON.

Mounting:2 bolt flange - see interfacedimensions.

Weight:4 lbs., 2 oz., shipped oil-filled.

NOTE: To assure compliance withNational Fire Protection AssociationBulletin 31, “Installation of OilBurning Equipment”, fuel unit inletpressure should not exceed 3 psig.

Dimensions in inches, ( ) = cm