Preventive Maintenance, Inspection, and Customer Service
Module Introduction
This chapter covers the essential cross-cutting skills of the recreational vehicle (RV) service technician trade. Although often perceived as "secondary" compared to diagnosis or repair, preventive maintenance tasks, systematic inspection, and customer service represent a significant portion of the Red Seal interprovincial exam. Questions focus on procedure, order of operations, safety standards, and professional communication. A candidate who masters this module demonstrates an understanding of the complete lifecycle of an RV, from delivery to periodic maintenance.
Section 1: Foundations of Preventive Maintenance
1.1 Definition and Objectives
Preventive maintenance (PM) is the set of planned operations aimed at keeping an RV in a safe and reliable operating condition, preventing breakdowns, and extending the service life of components. Unlike corrective repair (which responds to a failure), PM is proactive and systematic.
The specific objectives are:
Ensure the safety of occupants and other road users (brakes, tires, hitch, gas).
Maintain the value of the vehicle (prevention of corrosion, moisture, deterioration of seals).
Reduce operating costs (fuel consumption, premature wear).
Detect incipient failures before they become critical (e.g., fatigue cracks on a chassis).
1.2 The Maintenance Schedule: Intervals and Criteria
There is no single universal schedule. The technician must refer to the RV manufacturer's manual AND the chassis manual (Ford, Chevrolet, Mercedes, etc.). Intervals are expressed in kilometres, operating hours (for generators), or calendar periods (e.g., annually, or before storage).
| Component | Typical Interval (Towable) | Typical Interval (Motorized) | Replacement Criteria |
|---|
| Tires | 5-7 years (manufacturing date) | 5-7 years | Wear, cracking, bulges |
| Drum brakes | 10,000 km or annually | 20,000 km | Lining thickness < 1.6 mm |
| Wheel bearings | 10,000 km or annually | 40,000 km | Play, noise, overheating |
| House battery (lead-acid) | Monthly check | Monthly check | Specific gravity < 1.225 (50% charge) |
| Generator | — | 100 hours or annually | Oil change, air filter |
| Propane system | Annual leak test | Annual leak test | Pressure drop > 0.5 kPa in 10 min |
| Roof sealant (EPDM rubber) | Semi-annual inspection | Semi-annual inspection | Cracks, peeling, porosity |
Golden Rule: An "annual" interval never replaces a "kilometre" interval. Whichever criterion is reached first takes precedence.
1.3 The Systematic Inspection Procedure (The 9 Points)
The Red Seal exam evaluates your ability to follow a logical sequence. The recommended method is the walk-around inspection, from the front bumper to the rear bumper, including the roof and undercarriage. Here are the 9 critical zones:
19.Hitch and chassis: Check the ball (wear, lubrication), safety chains, breakaway cable, hitch pin bolts (torque specification), presence of perforating rust.
20.Suspension and axles: Check shock absorbers (leaks), leaf springs (broken leaves), torsion axle bushings (play), axle alignment.
21.Tires and wheels: Cold pressure (per label), tread depth (legal minimum 1.6 mm, but 3 mm recommended for RVs), manufacturing date (DOT code: last 4 digits = week/year), wheel bolts (torque specification).
22.Braking system: For trailers, the breakaway switch must be tested by pulling the pin. The breakaway battery must hold its charge. Check the brake controller adjustment (gain).
23.Electrical system: Test lights (stop, turn signals, running lights, backup lights), test the 7-pin connector (pin 4 = 12 V, pin 2 = backup lights, pin 7 = electric brakes). Verify the ground connection.
24.Propane system: Leak test with a manometer (max 0.5 kPa drop in 10 min), inspect hoses (expiry date, cracking), check tank mounting brackets.
25.Water system: System pressure (max 550 kPa for PEX piping), check for leaks, condition of the pump, water heater operation (bypass, pressure relief valve).
26.Roof and sealants: Inspect seals (caulking), vents, roof hatch, solar panels (mountings). Check for blisters or delamination.
27.Interior and appliances: Test the CO detector (replace at 5-7 years), propane detector, fire extinguisher (pressure, date), operation of the stove, refrigerator (absorption), furnace.
Section 2: In-Depth Technical Inspection
2.1 Trailer Braking System
Trailers over 1,500 kg (3,000 lb) must be equipped with electric brakes. The technician must know the power test: measure the current (in amps) at the brake magnets. A typical magnet draws 3 A per wheel at full power. The brake controller must supply voltage proportional to the tow vehicle's braking.
Drum Brake Adjustment Procedure:
33.Raise the wheel and spin it.
34.Insert a screwdriver through the access hole in the backing plate.
35.Turn the star wheel until the lining contacts the drum.
36.Back off 10 to 12 clicks (or until the wheel spins freely with a slight drag).
Breakaway Switch Test: Pull the pin. The brakes must lock (or at minimum create strong resistance) within 2 seconds. The device's battery must be recharged and tested (voltage ≥ 12.4 V).
2.2 The 12 V and 120 V Electrical Systems
The RV has two distinct electrical systems. The technician must identify the standard wire colours (Canadian Electrical Code, Part I):
| Voltage | Wire | Colour | Function |
|---|
| 120 V | Hot | Black or red | Supply |
| 120 V | Neutral | White | Current return |
| 120 V | Ground | Green or bare | Protection |
| 12 V | Positive | Red | Supply |
| 12 V | Negative | White or black | Return (ground) |
Rule 8-200 of the Canadian Electrical Code, Part I: Conductors must be protected against overcurrent (fuses or circuit breakers) at the point of supply. Each 120 V circuit must have an appropriately sized breaker (15 A for 14 AWG wire, 20 A for 12 AWG wire).
Polarity Test: Use a multimeter to verify that the hot wire is on the "hot" terminal of the receptacle. A polarity reversal is an immediate hazard.
2.3 The Propane System (CSA B149.1 Standard)
The CSA B149.1 (Natural Gas and Propane Installation Code) applies to RVs. Essential points for the exam:
Leak Test: The system must be pressurized to the test pressure (generally 1.5 times the service pressure, but never less than 350 kPa). The maximum allowable pressure drop is 0.5 kPa in 10 minutes after stabilization.
Hoses: Connection hoses (tank → regulator) have a maximum service life of 10 years (stamped date). They must be replaced if they show cracking, cuts, or bulging.
Regulator: The outlet pressure must be 2.75 kPa (11 inches of water column) for low-pressure appliances. A regulator that "freezes" (frosts over) indicates a flow problem or an overfilled tank.
Tank: The pressure relief valve must be oriented downward (to vent liquid). The tank must be securely mounted (metal bracket, bolts ≥ 8 mm).
Propane detector: Installed 15 cm from the floor (propane is heavier than air). It must be tested with a test aerosol (never with a flame).
2.4 The Potable Water System
The fresh water tank, piping, and water heater must be inspected and disinfected. The disinfection procedure (Public Health Agency of Canada standard):
52.Drain the tank.
53.Prepare a bleach solution (5.25% hypochlorite) at a rate of 50 ppm (50 mL of bleach per 100 L of water).
54.Fill the tank with this solution, open all taps until the chlorine odour is detected.
55.Let it sit for 4 hours minimum.
56.Drain and rinse thoroughly (2 times).
Pressure Test: The system must withstand a pressure of 550 kPa without leaking. Never exceed 700 kPa (risk of PEX fitting failure).
Section 3: Customer Service
3.1 Technical Communication
The technician is an intermediary between the customer and the machine. Communication must be clear, honest, and documented. Key principles:
Active listening: Rephrase the customer's complaint ("You're saying the refrigerator doesn't cool on propane mode, is that correct?").
Diagnosis explanation: Use accessible vocabulary, avoid jargon. Show the defective part to the customer if possible.
Expectation management: Provide a written estimate of cost and time. Mention possible additional costs (parts not visible before disassembly).
Informed consent: Never perform unauthorized repairs. Obtain a signature on the estimate.
3.2 The Work Order (Repair Order)
The work order is a legal document. It must contain:
68.Customer information (name, contact details).
69.RV information (make, model, year, VIN).
70.Kilometrage or hours.
71.Description of the complaint (customer's words).
72.List of operations performed (with dates).
73.Parts used (part numbers, quantities, prices).
74.Labour time (in hours or tenths of an hour).
75.Test results (pressures, voltages, etc.).
Frequent Error: Not recording measured values before replacement. A good technician documents the evidence of the diagnosis.
3.3 Vehicle Delivery (Handover to Customer)
Delivery is a customer training step. The technician must:
Explain the operation of the repaired systems.
Demonstrate safe usage (e.g., lighting the refrigerator, purging the water system).
Hand over manuals and warranties.
Explain the limitations of the repair (e.g., "The roof sealant has been redone, but the roof will need to be replaced within 2 years").
Obtain the customer's signature confirming receipt.
3.4 Complaint and Return Management
An RV that comes back with the same problem is a learning opportunity. The professional procedure:
86.Reception: Listen without interrupting, note the facts.
87.Verification: Review the initial diagnosis, check the installed parts.
88.Hypotheses: Consider a secondary cause (e.g., a short circuit can be caused by a pinched wire, but also by an overvoltage from the converter).
89.Solution: Offer a correction at no charge if the error was yours, or clearly explain why the problem is different.
90.Follow-up: Call the customer after 48 hours to confirm satisfaction.
Section 4: Useful Calculations and Measurements
4.1 Pressure, Surface Area, and Load
Tire pressure: The recommended pressure is indicated on the manufacturer's label (never on the tire sidewall). For an RV, cold pressure must be checked before departure (tires not heated by the road).
Hitch load: The vertical load on the hitch ball must represent 10 to 15% of the trailer's total weight. Example: a 3,000 kg trailer must have a hitch load of 300 to 450 kg.
Ohm's Law: U = R × I. For a 12 V light circuit with a 21 W bulb, the current is I = P / U = 21 / 12 = 1.75 A.
4.2 Capacity and Autonomy
Battery: A 100 Ah (amp-hour) battery powering a refrigerator that draws 5 A will theoretically last 100 / 5 = 20 hours. In practice, you never discharge a lead-acid battery beyond 50% (actual duration: 10 hours).
Propane: A 30 lb (13.6 kg) tank contains approximately 0.68 m³ of gas. A refrigerator consumes about 0.15 kg/24 h. Autonomy ≈ 13.6 / 0.15 = 90 days (theoretical, without heating).
Generator: A 3,500 W generator consumes about 1.5 L/h at 50% load. With a 20 L tank, autonomy ≈ 13 hours.
4.3 Useful Conversions
| Imperial Unit | Metric Unit | Factor |
|---|
| 1 inch (in) | 25.4 mm | × 25.4 |
| 1 foot (ft) | 0.305 m | × 0.305 |
| 1 pound (lb) | 0.454 kg | × 0.454 |
| 1 psi | 6.895 kPa | × 6.895 |
| 1 US gallon | 3.785 L | × 3.785 |
| 1 Imperial gallon | 4.546 L | × 4.546 |
Trap: The Canadian (Imperial) gallon is larger than the US gallon. A 40 US gallon water tank = 151 L, but 40 Imperial gallons = 182 L. Always verify the unit.
Section 5: Federal Standards and Regulations
5.1 The Canadian Electrical Code, Part I
This code applies to recreational vehicles and manufactured homes. Key points:
Rule 8-200: Overcurrent protection (fuses/breakers) for each circuit.
Rule 8-300: Grounding of the chassis and exposed metal masses.
Rule 8-400: Conductors must be protected against abrasion (routed through conduits or grommets).
Rule 8-500: 120 V receptacles must be GFCI (ground fault circuit interrupter) type in wet areas (washroom, kitchen, exterior).
5.2 The CSA B149.1 Standard (Gas)
Article 5.8: Appliances must be installed with minimum clearance from combustible materials (indicated on the nameplate).
Article 6.2: Gas piping must be supported at maximum intervals of 1.5 m.
Article 6.14: A shut-off valve must be installed at each appliance.
Article 7.3: Appliance connection hoses must not exceed 1.5 m in length.
5.3 The CSA Z240 Standard (Series)
The CSA Z240 series covers recreational vehicles (Z240 RV Series). It specifies requirements for construction, fire safety, ventilation, and structural strength. The technician must know:
Z240.2.1: General requirements (structure, chassis).
Z240.4.1: Electrical requirements (supplement to the Canadian Electrical Code).
Z240.6.1: Plumbing requirements (potable water, grey water).
Section 6: Storage and Commissioning Procedures
6.1 Winterization (Winter Preparation)
In Canada, winterization is a major operation. The complete procedure:
126.Water system: Drain the tank, piping, and water heater (open the pressure relief valve and remove the drain plug). Blow out the lines with compressed air (max 280 kPa) to remove residual water. Add non-toxic antifreeze (propylene glycol) to the P-traps and grey water tank.
127.Propane system: Close the tank valve. Purge the lines by briefly lighting a burner. Never leave gas in the lines without pressure.
128.Electrical system: Disconnect the battery (or keep it on a battery maintainer). Remove batteries that can freeze (a discharged battery freezes at -10 °C, a charged battery at -60 °C).
129.Tires: Inflate to the maximum recommended pressure (or raise the RV on jack stands to unload the tires).
130.Interior: Leave cabinet doors open, place a dehumidifier, cover vents with insulated covers.
131.Exterior: Clean the roof, apply UV protectant to sealants, cover the RV with a breathable tarp (never impermeable plastic).
6.2 Commissioning (Season Start-Up)
Commissioning is the reverse of winterization, with additional checks:
134.Tire inspection: Check pressure, manufacturing date, cold-related cracking.
135.Braking system: Test the breakaway switch, check drums for surface rust.
136.Propane system: Complete leak test (mandatory after storage).
137.Water system: Flush the system with a disinfection solution (50 ppm chlorine), purge air from the lines.
138.Batteries: Fully recharge, check electrolyte level (open lead-acid batteries), clean terminals.
139.Appliances: Light the refrigerator (electric mode first, then propane), test the furnace (check the exhaust vent for bird nests), test the stove.
Section 7: Technician Safety
7.1 RV-Specific Hazards
Propane: Risk of explosion and asphyxiation. Work in a ventilated area. Use a portable gas detector. Never use a flame to detect a leak (use a soapy solution or an electronic detector).
120 V electricity: Risk of electrocution. Cut the power before working. Verify the absence of voltage with a tester. Wear insulated gloves.
Weight and lifting: A full water tank weighs 1 kg/L. A lead-acid battery weighs 20-30 kg. Use safe lifting techniques.
Asbestos: Some older RVs (pre-1980) may contain asbestos in brake pads or insulation. Never sand or blow out these materials.
Carbon monoxide: Never run an engine or generator in an enclosed space. Use a personal CO detector.
7.2 PPE (Personal Protective Equipment)
| Task | Required PPE |
|---|
| Propane testing | Nitrile gloves, safety glasses |
| Electrical work | Insulated gloves (Class 0), glasses |
| Grinding / drilling | Safety glasses, hearing protection |
| Battery handling | Rubber gloves, glasses (acid risk) |
| Working under the RV | Safety helmet, glasses |
Pitfalls to Avoid
152.Confusing the US gallon and the Imperial gallon: Always check the tank label. A 20% error in antifreeze calculation can cause frozen pipes.
153.Forgetting the breakaway switch test: This is the most critical safety feature of a trailer. The exam almost always includes a question on the test procedure (pull the pin, check the battery).
154.Using the maximum tire pressure (printed on the sidewall) as the inflation pressure: The correct pressure is the one on the RV manufacturer's label, which accounts for the actual load.
155.Neglecting the tire manufacturing date: A tire with 80% tread but 8 years old must be replaced. The DOT code (last 4 digits) is a frequent exam question.
156.Testing a propane leak with a flame: This is prohibited and dangerous. Use a soapy solution (bubbles) or an electronic detector.
157.Not documenting measurements: A work order without measured values (voltage, pressure, amperage) is considered incomplete during the practical evaluation.
158.Confusing the CO detector and the propane detector: CO is lighter than air (installed 1.5 m from the floor), propane is heavier (installed 15 cm from the floor).
159.Forgetting the water heater pressure relief valve: It must be manually operated at least once a year to verify it is not stuck.
160.Tightening wheel bolts in a cross pattern with excessive torque: The typical torque is 110-120 N·m for steel rims, but always check the manufacturer's specification.
161.Not checking polarity before connecting an RV to 120 V: A polarity reversal can damage electronic appliances and create an electrocution risk.
Summary
Preventive maintenance is a systematic and documented procedure, based on manufacturer intervals (kilometres, hours, calendar).
The 9-point inspection (hitch, suspension, tires, brakes, electrical, propane, water, roof, interior) is the reference method.
The trailer braking system must be tested with the breakaway switch (pin pulled) and the current at the magnets (3 A per wheel).
The propane system is governed by the CSA B149.1 standard: leak test at 350 kPa, max drop of 0.5 kPa in 10 min, hoses limited to 10 years.
The electrical system is governed by the Canadian Electrical Code, Part I: breaker protection, grounding, GFCI receptacles in wet areas.
Customer service requires clear communication, written consent, and complete documentation of measurements and operations.
Winterization and commissioning are inverse but complementary procedures, with mandatory safety checks (gas test, water disinfection).
Basic calculations (Ohm's Law, battery capacity, propane autonomy, imperial/metric conversions) are essential for the exam.
Self-Assessment Questions (Red Seal Style)
174.A customer asks you to check the propane system of a travel trailer. The manometer shows a pressure drop of 0.8 kPa in 10 minutes. What do you do?
Answer: The drop exceeds the 0.5 kPa limit. You must search for the leak (soapy solution on all fittings), repair it, then re-run the test.
176.What is the correct inflation pressure for RV tires?
Answer: The one indicated on the RV manufacturer's label (not the one on the tire sidewall).
178.A propane detector is installed 1.2 m from the floor. Is this correct?
Answer: No. Propane is heavier than air; the detector must be 15 cm from the floor.
180.You are replacing a house battery. The new battery has a capacity of 120 Ah. The refrigerator draws 6 A. What is the practical autonomy (without going below 50% discharge)?
Answer: (120 Ah × 0.5) / 6 A = 10 hours.
182.A customer complains that the refrigerator does not work in propane mode. What is the first check?
Answer: Verify that the propane shut-off valve is open and that the tank contains gas (gauge). Then, check the ignition spark and flame.
This chapter prepares you for the theoretical and practical questions of the interprovincial exam. Review the cited standards, memorize the limit values (0.5 kPa, 50 ppm, 10 years, 15 cm), and practice documenting every intervention as if it were being evaluated.
