DEF Winterization Field Reference Guide

Category: Equipment Maintenance / Seasonal Operations Region: All (Climate-Dependent) Last Updated: 12/25/2024 Cross-Reference: Error Codes Reference, STP Troubleshooting

Quick Reference

DEF Freeze Point: 12°F (-11°C) Expansion When Frozen: ~7% Heat-ON Setpoint: 35°F (2°C) Heat-OFF Setpoint: 45°F (7°C) Max Winter Tank Fill: 70-75%

Gilbarco Technical Support: 1-336-547-5000 Benecor Support: 1-844-BENECOR (1-844-236-3267)

1. DEF Chemistry Fundamentals

The 32.5% urea concentration represents the eutectic point - both urea and water freeze simultaneously at the lowest possible temperature. Any concentration above or below this percentage has a higher freeze point.

CRITICAL: Additives are strictly prohibited. Anti-freeze or anti-gel products alter concentration and contaminate the fluid.

| Property | Value | Field Implication | |----------|-------|-------------------| | Freeze point | 12°F (-11°C) | Heat systems must maintain above this | | Expansion rate | ~7% when frozen | Never fill tanks above 90% capacity | | Specific gravity | 1.09 at 68°F | Slightly heavier than water | | Density | 9.07-9.12 lbs/gallon | Important for tank weight calculations | | pH range | 7.0-8.5 | Mildly corrosive to many metals |

Shelf Life vs Temperature

| Storage Temp | Shelf Life | |--------------|------------| | ≤60°F | 36 months | | 77°F | 18 months | | 86°F | 12 months | | 95°F | 6 months |

Ideal maintenance temperature: 40-50°F - warm enough to prevent freezing, cool enough to maximize shelf life.

2. Heat Trace Systems

Self-regulating heat trace cable is preferred over constant-wattage - it automatically adjusts output based on temperature and can be overlapped at valves and fittings without creating hot spots.

Wattage Requirements by Climate

| Climate Condition | Required Wattage | Application | |-------------------|------------------|-------------| | Mild (above 20°F typical) | 3-5 W/ft | Basic freeze protection | | Moderate (0-20°F) | 5-8 W/ft | Standard DEF installations | | Severe (below 0°F) | 10-15 W/ft | Northern plains, mountain regions |

Recommended Products

| Product | Specs | Application | |---------|-------|-------------| | Chromalox SRM/E 388210 | 10 W/ft, 120V, self-regulating | Most DEF applications | | Chromalox SRM/E 388244 | 10 W/ft, 240V | 240V systems | | Raychem WinterGard 196811-000 | 6 W/ft, 120V, max 200 ft | Lighter duty | | Chromalox End Seal Kit 383574 | 5 per kit | Weatherproof terminations | | Chromalox Splice/Tee Kit 383558 | - | Junction points and repairs | | Chromalox Line-sensing Thermostat 389600 | 40°F preset, 22A, -40°F to 160°F | Temperature control |

Installation Fundamentals

• Apply heat trace along pipe bottom (6 o'clock position for horizontal runs)
• Secure with aluminum tape every 12 inches
• Provide 2-3 feet of extra cable looped around valves, pumps, and fittings
• Install insulation OVER the heat trace - minimum 1" thickness (1.5-2" for severe cold)
• Always install weatherproof jacket over insulation for outdoor applications

3. Controller Programming

| Parameter | Setpoint | Purpose | |-----------|----------|---------| | Heat-ON activation | 35°F (2°C) | Maintains margin above freeze | | Heat-OFF deactivation | 45°F (7°C) | Prevents excessive heating | | Differential/deadband | 5-10°F | Prevents short cycling | | Low temperature alarm | 20°F (-7°C) | Critical freeze risk warning | | High temperature alarm | 65-85°F (18-30°C) | Degradation risk warning |

Sensors: Use PT100 RTDs (Resistance Temperature Detectors) for accuracy - ±0.15°C to ±0.3°C depending on class. Ensure sensors are attached to pipe surfaces, not suspended in air.

4. Material Compatibility

ISO 22241 specifies extremely tight contamination limits - as little as 0.2 ppm of copper, zinc, or chromium can render DEF unusable and damage SCR catalysts.

One tablespoon of table salt contaminates approximately 3 gallons of DEF.

| Approved Materials | NEVER Use | |-------------------|-----------| | 316/304 Stainless Steel | Copper or brass | | HDPE Polyethylene | Zinc (galvanized) | | Polypropylene | Aluminum | | PTFE (Teflon) | Carbon steel | | Viton (FKM) elastomers | Chrome-plated fittings | | EPDM rubber | Nickel-plated fittings |

316 stainless steel is preferred for all wetted metal components (contains molybdenum for superior corrosion resistance).

5. Pre-Winter Preparation Checklist

Complete before the first freeze of the season (September-October).

System-Wide Inspection

• [ ] Inspect dispenser cabinet for damage, bent sheathing, missing door magnets
• [ ] Check all door seals and gaskets for proper closure
• [ ] Verify insulation is intact throughout system
• [ ] Clean crystallized DEF deposits from fittings and nozzle boots
• [ ] Inspect for leaks at all connections
• [ ] Verify tank level is 50-70% (allows for 7% freeze expansion)

Heat Trace Testing Protocol

1. De-energize and lock out the circuit
2. Continuity test: Measure resistance between bus wires - should show 0.1-1.0 ohms typical
3. Megger test: Apply 2500 VDC between bus wires and ground braid - minimum 20 megohms acceptable, 2000+ megohms ideal
4. Re-energize and measure amp draw: Compare to specifications (cold startup draws 2-3x normal for self-regulating cable)
5. Temperature verification: Use contact thermometer or thermal imaging to verify pipe surface above 32°F throughout

Electrical Verification

• [ ] Verify breaker status and sizing (account for inrush current)
• [ ] Check all power connections for corrosion or damage
• [ ] Verify ground fault protection is functional
• [ ] Confirm controller displays correct readings
• [ ] Test high/low temperature alarms

6. Filter Maintenance

DEF filters require more frequent replacement than fuel filters - SCR systems are extremely sensitive to particulate contamination.

Specifications

| Parameter | Recommendation | |-----------|----------------| | Micron rating | 5 micron (absolute) - optimal balance | | Alternative | 10 micron for longer intervals | | Housing material | 316L stainless steel required | | Efficiency | Beta 5000 (99.98% retention) |

Replacement Indicators

• Decreased flow rate at dispenser (primary indicator)
• Longer customer fill times
• Visible crystallization on filter housing
• High differential pressure across filter
• Dispenser fault codes related to flow

Recommended Products

• PetroClear DEF-E5: 5 micron absolute, 316L stainless, 7 GPM max
• PetroClear DEF-E10: 10 micron version
• Cim-Tek D.E.F.-TEK: Designed for DEF particulate and crystal removal

7. Safe Thawing Procedures

Prohibited Heat Sources

• Open flame (propane torch, blowtorch)
• Kerosene or propane heaters directed at equipment
• Hair dryers on high heat settings
• Any direct high-heat application to plastic components
• Additives of any kind (destroys DEF permanently)

Approved Thawing Methods (In Order of Preference)

1. Built-in heating system: Repair and activate if possible
2. Cabinet/enclosure heating: Raise ambient to 50-60°F
3. Heat blankets/wraps: Low wattage, thermostatically controlled
4. Portable space heater: Heat the area, not direct on equipment
5. Hot towels: Wrap and replace as they cool

Expected Thaw Times

| Component | Thaw Time | Notes | |-----------|-----------|-------| | Nozzle/hose | 15-30 minutes | Usually first to thaw | | Small lines (≤1") | 30-60 minutes | With proper heat application | | Large lines (>1") | 1-3 hours | Depends on frozen volume | | Pump assembly | 1-2 hours | Inspect carefully after | | DEF tank/tote | 4-24+ hours | Do not rush |

Post-Thaw Inspection

• [ ] Full flow restored at all points
• [ ] Visual inspection complete - no cracks, bulges, or leaks
• [ ] All connections verified tight
• [ ] No frost remaining on components
• [ ] Operating temperature reached throughout
• [ ] Heat trace system verified operational
• [ ] Dispense small test quantity to verify quality

8. Troubleshooting Winterization Failures

Diagnostic Flowchart - Non-Flowing DEF Dispenser

System Not Dispensing
        │
        ├─► Check power at breaker
        │   └─► Tripped? → Check for ground fault, reset and monitor
        │
        ├─► Verify heat trace amperage
        │   └─► Zero amps? → Open circuit - locate break with megger
        │   └─► Low amps? → Damaged sections - thermal scan for cold spots
        │
        ├─► Check thermostat operation
        │   └─► Not calling for heat? → Verify setpoints, sensor location
        │   └─► Stuck on? → Replace controller or relay
        │
        └─► Inspect insulation
            └─► Wet or compressed? → Replace immediately (loses R-value)

Heat Trace Failure Modes

| Symptom | Likely Cause | Solution | |---------|--------------|----------| | Breaker trips immediately | Short to ground | Megger test to locate, replace damaged section | | Breaker trips at cold startup | Inrush exceeds rating | Verify circuit length, consider slow-trip breaker | | No heat output | Open circuit | Continuity test, replace failed section | | Uneven heating | Localized damage | Thermal scan, repair or replace affected area | | Continuous operation | Controller/sensor failure | Replace thermostat, verify sensor attachment |

Pump Damage Assessment After Freeze

Before attempting operation:

• Check for visible cracks in housing
• Look for fluid leaking from shaft seal
• Verify motor rotation (may be seized)
• Test flow rate against specification (>80% of rated = pass)
• Test pressure output against specification
• Listen for grinding, cavitation, or unusual noise

Repair vs Replace Decision

Replace when:

• Repair cost exceeds 50-60% of new component cost
• Multiple damage points exist
• Megger readings fall below 1 megohm
• Safety-critical components damaged (pressure vessels, relief valves, emergency shutoffs)

Repair when:

• Damage is localized
• Parts are readily available
• Component is under 5-7 years old

9. Manufacturer-Specific Features

Gilbarco Veeder-Root

Encore DEF Dispensers:

• Thermostat-controlled heated cabinets rated to -22°F (-30°C)
• Heated nozzle boots
• DEF recirculation systems (circulate product continuously)
• Red Jacket CoreDEF submersible pump (3/4 HP and 2 HP options)
• Integrates with TLS-450PLUS DEF Recirculation Software Feature

Key advantage: 4-year corrosion warranty - best in industry

Support: 1-336-547-5000 | gilbarco.com

Wayne Fueling Systems (Dover)

Ovation Series Model Designations:

• Ovation HD: Diesel + Cold Climate DEF (insulated and heated)
• Ovation HW: Diesel + Warm Climate DEF (unheated - for temps always above 12°F)
• Vista DEF: Standalone dispenser with optional heater

Patented Feature: Self-closing nozzle and hose doors automatically close when not in use to prevent freezing.

Model Codes: "3" = cold-climate DEF module on right of A side; "4" = left side

Gasboy (Gilbarco Veeder-Root)

AtlasX DEF Dispensers:

• Cold Weather Models (8862G/9862G): Thermostatically controlled heated cabinet, internal hose storage, enclosed heated nozzle hang-up, rated to -30°C (-22°F)
• Part numbers: 9860KX-Z, 9862KX-Z, 8862KX-Z for cold weather

OPW DEF Components

• 21Gu DEF Nozzle: 19mm spout per ISO 22241, 50 PSI max, NEWGARD hand insulator
• 66SB Swivel Breakaway: 360° rotation, 175-330 lb separation force

Installation Note: Use gas/oil-approved non-hardening thread sealant only - never PTFE tape on DEF connections. Torque to 25-30 ft-lbs.

DEF Hose Part Numbers:

• 21GU-H17G: 17.4 ft for Gilbarco/Wayne dispensers
• 21GU-H11: 11 ft for Bennett/Gasboy dispensers

Benecor DEF Systems

• KDH-100-120V (Standard): Freeze protection to 0°F (-17°C), 120V strip heater, insulated tank enclosure
• KDH-100-24VX (Extreme): Freeze protection to -40°F (-40°C), 24V enhanced heating

Systems available from 20 gallons to 20,000 gallons with in-house insulation foaming.

Support: 1-844-BENECOR (1-844-236-3267) | benecor.com

10. Regulatory Compliance

ISO 22241 Requirements

| Parameter | Specification | |-----------|---------------| | Urea concentration | 32.5% ±0.7% (31.8-33.2% acceptable) | | Maximum metals contamination | 0.2-0.5 ppm depending on element |

Maximum Contamination Limits:

| Contaminant | Limit | Contaminant | Limit | |-------------|-------|-------------|-------| | Calcium | 0.5 ppm | Copper | 0.2 ppm | | Iron | 0.5 ppm | Zinc | 0.2 ppm | | Aluminum | 0.5 ppm | Chromium | 0.2 ppm | | Sodium | 0.5 ppm | Nickel | 0.2 ppm | | Magnesium | 0.5 ppm | Phosphorus | 0.5 ppm |

API Certification

Look for the API certification mark on all DEF products. Maintain Certificates of Analysis from suppliers documenting urea concentration, density, and metals analysis for each batch.

Storage Tank Requirements

• Approved materials: HDPE (most common), cross-linked polyethylene, polypropylene, 316/304 stainless steel, fiberglass reinforced plastic
• Secondary containment: 100% of largest container plus freeboard
• Tank venting mandatory - position to avoid moisture infiltration

11. Maintenance Schedule

Pre-Winter (September-October)

• Full system inspection per checklist
• Heat trace testing (continuity, megger, amp draw)
• Thermostat programming verification
• Insulation inspection and repair
• Filter replacement
• Tank level adjustment (50-70%)

During Winter (Monthly)

• Visual inspection for freeze damage
• Heating system operation verification
• Flow rate monitoring
• Crystallization inspection at fittings
• Nozzle boot cleaning
• Tank level check

Post-Winter (March-April)

• Full system inspection
• Tank cleaning if needed
• Filter replacement
• Thermostat adjustment or heating system shutdown
• Documentation of any winter issues for following season

12. Quick Reference Specifications

| Parameter | Specification | |-----------|--------------| | DEF freeze point | 12°F (-11°C) | | DEF expansion when frozen | ~7% | | DEF composition | 32.5% urea, 67.5% deionized water | | Heat-ON setpoint | 35°F (2°C) | | Heat-OFF setpoint | 45°F (7°C) | | Max tank fill level (winter) | 70-75% | | Min tank level (winter) | 50% | | Filter micron rating | 5-10 micron absolute | | Heat trace wattage | 5-10 W/ft typical | | Megger test minimum | 20 megohms | | Pressure test | 1.5× operating pressure, 10 min hold | | Shelf life (≤60°F storage) | 36 months | | Shelf life (≤77°F storage) | 18 months |

Related Documentation

• Error Codes Diagnostic Reference - DEF dispenser error codes
• STP Troubleshooting Guide - Pump-related diagnostics
• Wayne Dispenser Troubleshooting - Wayne-specific procedures

Field reference guide for DEF winterization procedures. The 12°F freeze point, 7% expansion rate, and extreme contamination sensitivity drive every equipment and procedural requirement. Pre-winter preparation in September/October prevents emergency service calls in January.