ELEMENT WILL NOT HEAT PROPERLY

Cause

Heater insulation is wet and element is connected to an ineffective ground. Wet electrical insulation will allow some amount of voltage to pass to ground. If the ground connection is poor, the voltage will pass through the lowest resistance current path available.

Solution

This is a hazardous condition. Shut off power and investigate source immediately. Make sure the ground connection is secure and that a conductive uninterrupted ground path exists to the ground source. Have a qualified electrician or testing service verify the grounding system. Remove or replace any non-copper or insulating material that exists in the path and test. Test heater insulation values as noted in section 7 and replace heater as required.

Cause

Heater ground lead connected directly to power. This condition would allow full voltage to pass through the ground lead to the path of least electrical resistance.

Solution

This is a hazardous condition. Shut off power and correct condition immediately. Make sure that the green ground lead has not been mistakenly connected as a power lead. If so, test heater for damage to the element, correct wiring and return to service.

Cause

Stray voltage/current from other sources entering tank through heater ground. Voltage from other devices with ineffective ground connections may pass through the heater ground connection if it is of lower resistance than the original device.

Solution

This is a hazardous condition. Shut off power and correct condition immediately. Test heater ground for voltage/current flow with heater power turned off to verify presence of flow. Locate source of voltage/current flow and correct condition

Cause

Low voltage. Any voltage below the design voltage of a resistance element significantly reduces the rated output of the heater.

Solution

Measure the available voltage and compare it to the rating on the tag. Check and compare your incoming voltage vs. the voltage at the heater. If the difference exceeds 5%, consider increasing the wire size. Either replace the heater, add more elements to increase capacity or provide voltage to match the rating on the tag.

Cause

Wrong voltage heating element supplied. Heaters operated on lower than design voltage will decrease in output.

Solution

Check nameplate to verify model number and proper voltage requirements. If wrong, replace heater. If they match, measure the resistance of each element to verify element and compare the measured value against the theoretical value. Replace as required.

Cause

One leg/phase out on three-phase power supply. This condition will apply full power to only one element, causing the heater to operate at about one half output.

Solution

Check power supply and protectors. Repair/replace as required.

Cause

Open element on heater. Since many heaters have multiple internal heating element coils, it is possible that one element could be open.

Solution

Measure the resistance with an ohmmeter and compare it to the theoretical value obtained using the nameplate volts and watts rating. If any leg varies by more than 10% of rated value, replace the heater.

Cause

Elements wired in a three-phase WYE connection versus a DELTA connection. This wiring method would de-rate the heater to one-third the rated output.

Solution

Check nameplate rating and verify correct wiring to match rated element value.

Cause

Elements wired in series. This condition would cause the heaters to produce about one quarter the rated output.

Solution

Check nameplate rating and verify correct wiring to match the rated value.

Cause

Wrong protector size. Protectors must be sized in accordance with the rating information stamped on heater nameplate/installation tag.

Solution

Replace with properly sized electrical protectors, as local codes require.

Cause

Wrong voltage applied to heater. Heaters operated at any voltage above the manufactured rating will increase in output and corresponding amperage draw.

Solution

DO NOT OPERATE HEATERS ABOVE RATED VOLTAGE. Either replace the heaters with units matching the available voltage or provide correct voltage to the heaters.

Cause

Wrong voltage heaters supplied. Heaters operated at any voltage above the manufactured rating will increase in output and corresponding amperage draw.

Solution

Check nameplate tag to verify model number and proper voltage requirements. If incorrect, replace heater. If they match, measure the resistance of each element and compare measured value against the theoretical value. Replace as required. Do not operate heaters above rated voltage.

Cause

Saturated/wet element insulation. Wet or saturated elements lose their electrical insulation and will leak voltage to ground, increasing the overall current draw.

Solution

Measure resistance between ground/sheath and power lead wires of heater. Resistance should exceed 40 megohms @500 VDC. If below this value, check solution for compatibility before replacing heater as most wet elements are caused by corrosion perforations in the sheath.

Cause

Measure resistance between ground/sheath and power lead wires of heater. Resistance should exceed 40 megohms @500 VDC. If below this value, check solution for compatibility before replacing heater as most wet elements are caused by corrosion perforations in the sheath.

Solution

Verify that the green ground lead is connected to a good earth ground, not the power supply. Correct wiring as required.

Cause

Improperly sized connection wire. Too small of gauge wire can cause resistance heating of wire and electrical connection.

Solution

Check heater ratings and wire size employed. Replace wiring and connections per National Electrical Code.

Cause

Loose wire connection to protector. Loose connections can cause resistance-heating damage to wires and protectors.

Solution

Check for any distortion or discoloration to wires or connection points and repair or replace as required.

Cause

Unbalanced load. Combining heaters of different wattage, or non-uniform groupings (not divisible by three for single-phase elements) will cause unbalanced electrical loads on one or more of the phases.

Solution

Multiple heaters should be wired in single phase parallel or three phase Delta/Wye configurations. Reducing the unbalanced heater load can be accomplished by using uniform heater sizes and individual three phase elements.

Cause

Low liquid level. Solution level must be maintained above heater's hotzone indicating standoff at all times.

Solution

Recommend the use of liquid level controls as the first line of defense against low level. Refill tank and reset P2 system.

Cause

Buildup on heater sheath. Any deposit on the heater sheath will act as a thermal insulator and cause localized overheating.

Solution

Inspect and clean heaters frequently. Check application, as de-rated heaters may be required in most solutions that buildup quickly. Clean heaters and reset P2 system.

Cause

Heavy or viscous solution. Unusually heavy, viscous or poorly conductive fluids reduce heat transfer around the element, causing localized overheating.

Solution

Check solution concentration or viscosity (may need chemical supplier’s property data or MSDS sheets to verify composition). May be able to use higher temperature sensors or de-rate heaters to reduce premature opening. Change P2 sensors/heaters as required.

Cause

Wiring of electrical load directly through bimetallic thermostat. Do not wire any heater load directly through the P2 sensor, as resistance heating and device failure will result.

Solution

P2 sensors should only be wired into the holding coil circuit of some type of latching relay. Any sensor exposed to over a 2 amp load and/or over 240 VAC service should be replaced.

Cause

Thermal cycling caused by low-level conditions. Repeated overheating degrades the switching point accuracy of the bimetallic sensors and may cause premature opening.

Solution

Suggest the use of a liquid level control as the primary control device. Replace P2 sensor as required.

Cause

Bimetallic sensor does not reset. Possible defective protector or wiring problem.

Solution

Verify wiring and test sensor for continuity at room and elevated temperature, and replace as required.

Cause

Low liquid level. Solution level must be maintained above the heater's hot-zone indicator standoff at all times to prevent the element from overheating. (note discoloration).

Solution

Recommend the use of liquid level controls as the first line of defense against low level. Replace protector with proper rated protector. Consult installation sheets for details.

Cause

Watt density too high. Unusually heavy, viscous or poorly conductive fluids reduce heat transfer around the element, causing localized overheating.

Solution

Check solution concentration or viscosity (may need chemical supplier’s MSDS sheets to verify). May be able to use higher temperature protectors or de-rate heaters to reduce opening. Replace protectors or recommend heater replacement as required. Consult installation sheets for details.

Cause

Protectors electrically overloaded. Excessive current flow through the thermal protectors will cause resistance heating through protector and a de-ration of the thermal set point.

Solution

Rewire heater using a contactor or relay to energize the heater and wire protector in series with contactor coil/thermostat circuit. Higher temperature thermal protectors may be considered in some applications. Consult factory and installation sheets for details.

Cause

High temperature solutions. Due to the proximity of the protector to the element, viscous liquids or solutions over 180°F may cause protector to open prematurely.

Solution

Replace protector with appropriate higher temperature protector. Consult installation sheets or catalog for details.

Cause

Main disconnect in an off position; open protector(s) or defective circuit breaker on main power supply or loose or disconnected wiring.

Solution

Verify power and electrical connections by measuring voltage with a voltmeter. Test, reset or repair connections as required.

Cause

Improper Wiring

Solution

Verify wiring with appropriate diagram and correct if necessary.

Cause

Single-phase power connected to lines L1/L2 instead of L1/L3 (combination type controls).

Solution

Correct power connection points and return to service

Cause

Damaged or defective power switch.

Solution

Replace switch.

Cause

Incorrect or defective control step-down transformer.

Solution

Verify connections, voltage rating and output on transformer and repair or replace as required.

Cause

Incorrect/excessive voltage applied to control.

Solution

Verify that applied voltage does not exceed 240 VAC. Add step-down transformer to system and replace damaged control.

Cause

Thermal protector not connected to terminal blocks in control.

Solution

Consult appropriate wiring diagrams and connect protector as required.

Cause

Improper Wiring

Solution

Verify wiring with appropriate diagram and correct if necessary.

Cause

Single-phase power connected to lines L1/L2 instead of L1/L3.

Solution

Correct power connection points and return to service

Cause

Possible defective thermostat.

Solution

See appropriate control installation manual and troubleshooting notes.

Cause

Damaged or defective power switch

Solution

Replace switch.

Cause

No power.

Solution

See section 1 of guide for various causes of power disruption

Cause

Protector removed during installation or prior servicing. WARNING: Do not operate heaters without thermal protection.

Solution

Verify proper protector by product type/operating temperature and replace as required. (See catalog or installation sheet for available temperature ranges).

Cause

Open protector will disable control/heater circuitry. See protector troubleshooting notes regarding thermal protectors in section 5 of this guide for details. WARNING: Do not operate heaters without thermal protection.

Solution

Making sure that all power is off, test thermal protector(s) for continuity with an ohm or continuity meter. Test/ replace as required. If bimetallic (P2) style sensor, allow sufficient time for cooling before system reset or testing.