J.Jeb Mfg. Co. J.Jeb Mfg. Co. Frequently Asked Questions
J.Jeb Mfg. Co. J.Jeb Mfg. Co. Diesel engine and fuel heater design and manufacturing
J.Jeb Mfg. Co. J.Jeb Mfg. Co.
J.Jeb Mfg. Co. J.Jeb Mfg. Co. J.Jeb Mfg. Co.
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HOW MUCH DOES IT COST TO OPERATE A BLOCK HEATER?

  • Electric cost is determined by kilowatt hour use (kw/hr). For example: a 1500 watt engine heater uses 1.5 (one and one half) kilowatt hour of electricity (1500 watt = 1.5 kilowatt).
  • If your electrical cost is $0.10 per kilowatt hour use, a 1500 watt engine heater would cost $0.15 (15 cents) per hour to operate. ($0.10 x 1.5kw/hr).
  • Multiply that 15 cents by the number of hours used per day, and that is cost of operation. 10 hours / day: ($0.15 / hour) x (10 hours) = $1.50
  • Your local utility provider can give more detailed information or call J.Jeb Customer Service.

HOW IS THE AMPERAGE RATING OF AN ENGINE HEATER DETERMINED?

  • By dividing the engine heater wattage by voltage rating of engine heater. Example: (1500 watt / 120 volt) = 12.5 amps
  • Amperage is determined by a formula contained in OHMS LAW, a series of formulas giving electrical information from known values. Such values as ohms resistance, amperage draw, watts, and volts can be determined. A copy of formulas contained in OHMS LAW can be obtained through J.Jeb Mfg. Co. customer service, found in electrical handbooks, or a local electrical supplier.

HOW LONG DOES IT TAKE FOR AN ENGINE HEATER TO HEAT AN ENGINE?

  • Figure on two or three hours for maximum temperature rise to be realized. However many factors determine what 'maximum temperature' will be. Outside (ambient) air temperature, wattage of engine heater, wind velocity (wind chill factor), protection of engine from wind chill, and actual voltage getting to engine heater are critical factors.

WILL 240 VOLT RATED ENGINE HEATERS BE LESS EXPENSIVE TO OPERATE?

  • No. Wattage determines cost per hour. The higher the voltage of a device (whether a motor, resistance heater, or light bulb) the more efficiently the power is delivered to the device. However, wattage is the AMOUNT of electricity delivered by voltage. The wiring for a 240 volt system is less expensive to install because the gauge of wire is thinner, circuit breaker size is less, and transformer sizing is reduced. Due to efficiency of power delivery, heaters are less affected by voltage drop and therefore more often deliver a higher percentage of rated heat output.

WHY NOT USE OIL PAN HEATERS SINCE OIL IS THICKER IN COLD WEATHER?

  • Cold oil in the pan does not make engine starting more difficult. In addition, oil is a poor conductor of heat and is easily damaged by too much heat. Due to required lower wattage of oil heater, insufficient heat is transferred from oil pan to critical points on engine where heat IS required (upper cylinder area). [WARNING: NEVER USE A HEATER DESIGNED FOR COOLANT AS AN OIL HEATER. Engine damaging carbon particles will form and heater will rapidly fail.] Oil heat is required (see J.Jeb series "OH" oil heaters) when extremely low ambient temperatures make oil so thick it will not be picked up by oil pump, causing oil starvation (low oil pressure) and excessive engine wear. Under normal circumstances, an in block engine heater will warm all engine oil in passages, oil pump, and in oil cooler. When engine is started, cold oil pan oil is sent through warmed oil pump, oil passages and oil cooler, quickly raising oil temperature and insuring correct viscosity for lubrication.

WHAT ARE GROUND FAULT INTERRUPTER CIRCUIT BREAKERS (GFI)?

  • GFI breakers (Ground Fault Interrupter) measure voltage input and leakage. When leakage exceeds 5 thousandths (0.005) of an amp variation, a voltage leak (or short) is assumed and the circuit is 'opened' (GFI) stopping flow of electricity and stopping the potentially harmful short from harming personnel. Sometimes 'nuisance' trips occur due to excessive moisture at connections, dirt or corrosion. These conditions can be reduced or eliviated by cleaning connections and/or providing seal at block heater to shore power cord connection (use #PK1212 recessed male plug connection when unprotected male plug is used and J.Jeb #WS-1 for extension cord end to block heater cord area). Dripping moisture, blowing snow, or wet conditions can combine with other factors to cause nuisance trips. Long distance between GFI breaker and engine heater can cause nuisance trips since electrical cord has very small leakage which can add up to 50% of nuisance trip in a 100' and greater distance. GFI breakers are part of the building code in industry and home use in bathrooms, outside outlets, swimming pools and hot tubs and places wet conditions are common.

CAN HEATING FUEL INCREASE MILES PER GALLON IN OPERATIONS?

  • Don't bet on it. Heating fuel above a certain temperature reduces horsepower output of engine. If engine is wasting the fuel to horsepower ratio to begin with (under normal operational load and weather conditions) then heating fuel can show as a MPG improvement.
  • Technically, engine horsepower ratings are based upon climate/temperature conditions of approximately 90°F(32°C). With each 10°F(5.6°C) increase in fuel temperature above 90°F, approximately 1% of rated horsepower is lost. This is due to increased volume of fuel due to heat. Increased volume has a corresponding decrease of BTU output, therefore loss of horsepower.

WHY DOES DIESEL FUEL CAUSE WINTER OPERATION PROBLEMS?

  • Paraffin (or wax) is the lubricant in diesel fuel that protects injectors from wear. Cold temperatures solidify normally liquid wax into crystals, not unlike snowflakes, which are too big to pass through fuel filters. When enough crystals attach to filter media, fuel flow is stopped and engine will not run properly. Depending on paraffin content, wax clogged filters occur at temperatures 15°F(8°C) or more below freezing. Referred to as 'cloud point', when fuel changes appearance from amber/clear color to a cloudy appearance.
  • As temperatures fall further, wax crystals increase in number and link together to a jelly consistency. This temperature is called 'pour point' (will not flow or 'pour' from a container). At this state, fuel cannot be drawn through fuel lines by engine fuel pump.
  • Many times, high water content of fuel causes ice formation at 90° or 45° fuel line fittings that will restrict fuel flow. Fuel can adsorb up to 2% of volume in water. Water, besides freezing, can foster growth of microorganisms, which may clog filters in warmer temperatures.
  • In either case, warming fuel with a fuel heater along with an effective fuel maintenance program will either reduce or eliminate these conditions.
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last updated on September 30, 1999