Heat Pump System

Complete removal and replacement of the heat pump system assembly, including evacuation and recharge of the refrigerant circuit used for cabin climate control and battery thermal management.

Warnings

Tools required

Parts

• Heat pump assembly × 1 — Use OEM specification
• Refrigerant line O-rings × 1 — Use OEM specification
• Heat pump mounting gasket × 1 — Use OEM specification
• R-1234yf refrigerant × 1 — Typically 2.5-3.0 lbs
• PAG oil for R-1234yf systems × 1 — Use OEM specification

Fluids

• EV Battery/Motor Coolant — 1 qt

Preparation

1. Park vehicle on level surface and engage parking brake
2. Verify battery state of charge is below 30% for high voltage safety procedures
3. Access high voltage disconnect located in rear compartment and follow lockout/tagout procedures per Rivian service manual
4. Wait minimum 10 minutes after HV disconnect for capacitor discharge
5. Verify zero voltage at HV bus using insulated high voltage multimeter
6. Raise vehicle on lift to comfortable working height
7. Remove front undertray panels to access heat pump assembly
8. Connect R-1234yf recovery machine and recover all refrigerant from system per EPA regulations
9. Document refrigerant quantity recovered for recharge reference
10. Place drain pan under heat pump assembly coolant connections

Procedure

1. 1

   Disconnect electrical connections
   Disconnect the main electrical connector from the heat pump compressor assembly. Release the locking tab and carefully pull connector away from compressor housing. Disconnect the temperature sensor connectors (typically 2-3 sensors) from the heat pump housing and refrigerant lines. Label all connectors for reinstallation.
2. 2

   Disconnect coolant lines
   Using appropriate line disconnect tools, release the quick-connect fittings on both coolant inlet and outlet lines at the heat pump assembly. Allow coolant to drain into drain pan. Expect approximately 1 quart of coolant loss. Cap or plug open coolant lines immediately to prevent contamination.
3. 3

   Disconnect refrigerant lines
   Remove the refrigerant line mounting bolts securing high and low pressure lines to the heat pump assembly. There are typically two lines each with bolt-on flare fittings. Carefully disconnect each line and immediately cap all open refrigerant ports with clean service caps to prevent moisture and contamination entry. Inspect O-rings and discard old O-rings.
4. 4

   Remove heat pump mounting hardware
   Locate and remove all heat pump assembly mounting bolts. The EDV 500 heat pump is typically secured with 4-6 mounting bolts to the front subframe or chassis. Support the heat pump assembly weight with a suitable stand or jack before removing final mounting bolts.
5. 5

   Remove heat pump assembly
   Carefully lower and maneuver the heat pump assembly away from the vehicle. The assembly weighs approximately 40-60 lbs. Be mindful of remaining wiring harnesses or brackets that may interfere with removal. Inspect mounting location for debris or damage.
6. 6

   Prepare new heat pump assembly
   Unpack new heat pump assembly and verify all components match the original unit. Install new mounting gasket if applicable. Add specified amount of PAG oil to new compressor as indicated in service documentation (typically oil is pre-charged, verify per manufacturer). Remove shipping caps from all refrigerant ports just before installation.
7. 7

   Install new heat pump assembly
   Position new heat pump assembly into mounting location, ensuring proper alignment with mounting holes and clearance for all lines and connectors. Support assembly weight with jack or stand while aligning.
8. 8

   Install mounting hardware
   Install all heat pump mounting bolts and tighten in a cross-pattern sequence to ensure even loading. Follow manufacturer torque specifications if available in service manual.
9. 9

   Reconnect refrigerant lines
   Install new O-rings on all refrigerant line fittings, lightly lubricating with PAG oil. Connect high and low pressure refrigerant lines to heat pump assembly, ensuring proper seating. Install and tighten line mounting bolts. Do not overtighten aluminum refrigerant fittings.
10. 10

    Reconnect coolant lines
    Connect coolant inlet and outlet lines to heat pump assembly quick-connect fittings. Ensure fittings are fully seated and locking tabs engage properly. Gently pull on lines to verify secure connection.
11. 11

    Reconnect electrical connections
    Reconnect all electrical connectors to heat pump compressor and temperature sensors using labels from disassembly. Ensure all locking tabs fully engage and connectors are properly seated.
12. 12

    Evacuate refrigerant system
    Connect vacuum pump to refrigerant service ports using manifold gauge set. Evacuate system to minimum 500 microns and hold vacuum for 30 minutes to verify system integrity and remove all moisture. Monitor vacuum gauge for any pressure rise indicating a leak.
13. 13

    Recharge refrigerant system
    Using refrigerant scale and charging equipment, add R-1234yf refrigerant to system per specification (use quantity recovered plus any specified additional amount from service manual, typically 2.5-3.0 lbs total system capacity). Charge liquid refrigerant into low side with compressor off until system pressure stabilizes.
14. 14

    Refill coolant system
    Top off EV coolant system at reservoir to proper level using EV Battery/Motor Coolant specification. Follow coolant bleeding procedure per Rivian service manual to remove air from thermal management system.

Reassembly

1. Reinstall all undertray panels and secure with all original fasteners
2. Perform refrigerant leak test using electronic leak detector at all service connections and heat pump assembly
3. Verify all electrical connectors are properly secured and routed away from heat sources
4. Check coolant system for leaks at all connections while system is cold
5. Re-energize high voltage system following proper safety procedures and remove lockout/tagout device

Verification

• Start vehicle and activate climate control system in both heating and cooling modes to verify heat pump operation
• Monitor refrigerant pressures using scan tool or manifold gauges - typical pressures vary by ambient temperature but should stabilize within normal operating range
• Verify cabin heating and cooling performance meets factory specifications
• Check for proper coolant circulation and no leaks at heat pump connections after system reaches operating temperature
• Use scan tool to verify no diagnostic trouble codes related to climate control or thermal management systems
• Verify all temperature sensors are reading properly and heat pump compressor engages when commanded
• Test heated and cooled air output temperature at vents meets specification (typically 40-50°F in cooling, 120-140°F in heating)
• Perform final refrigerant leak test at all connections with system at operating pressure

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