From: Engine Block Heaters: Quick Starts for Standby Power
Specifying an Engine Block Heater
Step 1. Select the heater model.
Step 2. Determine engine in 3/liter displacement.
Step 3. Determine wattage required by using the general formula of 3 W x c.i.d (183 W x L); 3 x 855 = 2,565, which means a 2,500-W heater. (This formula is a rule of thumb for ambient temperatures above 0°F and will generally hold engine temperature at approximately 90°F above ambient. Specific requirements for heat rise in a required amount of time will require more complex calculations.); 500-W to 3,000-W heaters require 0.375-inch NPT fittings and 0.625-inch I.D. hose; 4,000-W to 6,000-W, 0.5-inch fittings and 0.75-inch I.D. hose. In heaters without pumps, the heat causes the coolant to rise, which results in circulation—provided the heater is properly installed. Mount the tank heater low relative to where the heated coolant is being put back in the engine, preferably below the lowest level of the coolant jacket, which maximizes the coolant to rise and induce flow. Check that the outlet hose does not have any downward trends from the point it leaves the heater to where it goes back into the engine. Any dips in the hose routing will cause flow restrictions and may prevent the heater from heating the engine. Also, look for any kinks in the hoses or fittings and for hoses that have been sized too small. Restrictions can cause the coolant to boil in the tank, and vaporized coolant cannot remove the heat from the element fast enough to keep it from overheating. Connect the heater outlet to a high point in the engine water jacket, preferably toward the rear, away from the engine thermostat.
Step 4. Determine the source voltage and phase available to power heater—120 V, 1 PH; 480 V, 3 PH.
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Step 5. Determine the engine temp to be maintained; 80°F to 100°F or 100°F to 120°F are common for genset applications.
—Adapted from information supplied by Kim Hotstart
July-August 2005
From: Engine Block Heaters: Quick Starts for Standby Power
Specifying an Engine Block Heater
Step 1. Select the heater model.
Step 2. Determine engine in 3/liter displacement.
Step 3. Determine wattage required by using the general formula of 3 W x c.i.d (183 W x L); 3 x 855 = 2,565, which means a 2,500-W heater. (This formula is a rule of thumb for ambient temperatures above 0°F and will generally hold engine temperature at approximately 90°F above ambient. Specific requirements for heat rise in a required amount of time will require more complex calculations.); 500-W to 3,000-W heaters require 0.375-inch NPT fittings and 0.625-inch I.D. hose; 4,000-W to 6,000-W, 0.5-inch fittings and 0.75-inch I.D. hose. In heaters without pumps, the heat causes the coolant to rise, which results in circulation—provided the heater is properly installed. Mount the tank heater low relative to where the heated coolant is being put back in the engine, preferably below the lowest level of the coolant jacket, which maximizes the coolant to rise and induce flow. Check that the outlet hose does not have any downward trends from the point it leaves the heater to where it goes back into the engine. Any dips in the hose routing will cause flow restrictions and may prevent the heater from heating the engine. Also, look for any kinks in the hoses or fittings and for hoses that have been sized too small. Restrictions can cause the coolant to boil in the tank, and vaporized coolant cannot remove the heat from the element fast enough to keep it from overheating. Connect the heater outlet to a high point in the engine water jacket, preferably toward the rear, away from the engine thermostat.
Step 4. Determine the source voltage and phase available to power heater—120 V, 1 PH; 480 V, 3 PH.
Step 5. Determine the engine temp to be maintained; 80°F to 100°F or 100°F to 120°F are common for genset applications.
—Adapted from information supplied by Kim Hotstart