Customer Makes Warranty Claim for Damage That Isn't Your Fault: How to Respond
Warranty vs misuse, manufacturer defect vs installation fault, investigation protocols, and the customer conversation that preserves relationships.
You installed a boiler 8 months ago. Customer calls: "It's broken—you need to fix it under warranty." You inspect it. Fault caused by customer turning off power during firmware update.
Here's how to investigate warranty claims, distinguish your fault from theirs, and respond without losing customers or money.
Warranty vs Misuse vs Normal Wear: The Legal Lines
UK Consumer Rights Act 2015 defines what you must cover vs what customers own:
Warranty Coverage Breakdown (UK Law)
YOU must fix (free under warranty):
- Installation faults: Work doesn't meet "reasonable skill and care" standard
- Faulty workmanship: Joints leak, connections fail, systems don't work as specified
- Defects present at installation: Issue existed when you completed work, even if discovered later
- Incorrect specification: You installed wrong-sized system, incompatible parts, etc.
CUSTOMER must pay for:
- Misuse/abuse: Using system beyond design limits (overloaded circuit, excessive pressure, etc.)
- Neglected maintenance: Didn't descale boiler, clean filters, follow care instructions you provided
- Third-party damage: Another tradesperson disturbed your work, customer DIY modifications
- Accidental damage: Physical impact, water ingress, environmental factors outside your control
- Normal wear and tear: Seals degrade, paint fades, materials age naturally within expected lifecycle
GREY AREA (investigate before deciding):
- Manufacturer defect: Boiler component fails due to factory fault (you fix labour free, customer pays parts OR claims manufacturer warranty)
- Pre-existing conditions: Old pipework corroded and finally failed (was it visible during install? Did you flag it?)
- Environmental factors: Extreme cold caused freeze damage (should you have specified freeze protection?)
The test: If fault would have occurred regardless of customer's actions because of how you installed it = your warranty. If fault only occurred due to customer's actions = not your warranty.
Investigation Protocol: Don't Respond Until You Know the Truth
Before you tell customer "not covered," investigate thoroughly:
Don't skip investigation. If you immediately say "not my fault" without evidence, customer assumes you're dodging responsibility. Investigate first = credibility.
Manufacturer Defect vs Installation Fault: Who Pays?
When installed product fails, determining fault determines cost:
| Failure Type | Who's Responsible | Who Pays What |
|---|---|---|
| Product failed due to manufacturing defect | Manufacturer | You: Free labour to remove/replace. Customer: Claims replacement part from manufacturer warranty OR pays for part if out of warranty. |
| Product failed due to incorrect installation | You | You: Free parts + labour to fix. Customer: Pays nothing (your workmanship warranty). |
| Product failed due to customer misuse | Customer | Customer: Pays for parts + labour at your standard rate. You: Invoice as normal chargeable work. |
| Product failed due to lack of maintenance | Customer | Customer: Pays for service/repair. You: Can offer at standard rate or slight discount as goodwill. |
| Product failed within first 30 days (Consumer Rights Act) | Presumed your fault | You: Must remedy free unless you can prove it's customer's fault (burden of proof on you). |
| Product failed 6-12 months after install | Depends on investigation | Customer: Must prove it was faulty at install OR you must prove it's misuse/wear. Investigate = determine responsibility. |
Pro tip: When manufacturer defect is clear, help customer claim from manufacturer warranty. You do labour free (goodwill), they get free part from manufacturer = both happy.
Response Scripts for Non-Warranty Claims (Without Losing Customers)
How to tell customer "not covered" without them feeling abandoned:
Non-Warranty Claim Response Scripts
Scenario 1: Failure caused by customer misuse
Customer: "The boiler's not working—you need to fix it under warranty."
You: "I've inspected the boiler and found the issue: the [component] failed because [specific cause: power was cut during update / filter wasn't cleaned / etc.]. Unfortunately, that's not a fault with the installation—it's [misuse/lack of maintenance]. My workmanship warranty covers installation faults, but not damage from [specific cause]. I can fix it for you at my standard rate, which would be £[amount]. Or if you'd prefer, I can show you what happened so you understand the cause. What works better?"
Scenario 2: Normal wear and tear
Customer: "The sealant is cracking—you said it would last."
You: "Sealant typically lasts 3-5 years depending on conditions. This was installed 18 months ago, and I can see it's degraded faster than expected—looks like [UV exposure/temperature fluctuations/water exposure] accelerated wear. That's not a fault with how I applied it; it's just the lifecycle of the material in this environment. I'm happy to re-seal it for £[amount], or I can show you how to maintain it yourself if you'd prefer."
Scenario 3: Third-party caused damage
Customer: "The wiring isn't working—you need to come back."
You: "I've looked at the circuit, and I can see someone has [disconnected/modified/added to] the wiring since I installed it. My original work is still intact, but the new connections are causing the fault. This isn't covered under my warranty because it's been altered after I completed the job. I can fix it and bring everything back to standard for £[amount]. Do you know who worked on it after me?"
Scenario 4: Manufacturer defect (you help customer claim)
Customer: "The tap cartridge has failed—you installed it 6 months ago."
You: "I've checked the installation—my work is sound, but the cartridge itself has failed. That's a manufacturing defect, not an installation fault. Good news: [Brand] has a 5-year warranty on parts. I'll help you claim the replacement cartridge from them, and I'll fit it for free as a goodwill gesture. That way you get a new part at no cost and I sort the labour. Sound fair?"
Scenario 5: Offering goodwill discount (borderline case)
Customer: "I know it might not be your fault, but I thought your warranty would cover this."
You: "Technically, this isn't a workmanship issue—it's [specific cause]. But I appreciate you're a good customer and I want to look after you. Here's what I can do: I'll fix it at cost price (materials + my hourly rate, no markup). Normally this would be £300, but I'll do it for £180. That's me meeting you halfway because I value the relationship. Does that work?"
When to Fix It Anyway (Goodwill vs Business Loss)
Sometimes fixing non-warranty issues free makes business sense:
| Scenario | Fix for Free? | Business Logic |
|---|---|---|
| Long-term repeat customer (£10K+ lifetime spend) | Yes | Relationship value > one-off fix cost; keeps future revenue secure |
| Small fix (under £100 cost to you) | Maybe | Goodwill gesture prevents bad review; low cost, high customer satisfaction |
| Borderline fault (50/50 whether your responsibility) | Yes | Avoid dispute; easier to fix than argue; protects reputation |
| High-profile customer (architect, surveyor, influencer) | Yes | Their referrals worth more than repair cost; marketing investment |
| Your spec/advice contributed to failure | Yes | Even if installation perfect, if your recommendation caused issue, you own it |
| First-time customer, clear misuse | No | Sets precedent; they'll expect free fixes forever; not sustainable |
| Customer ignored your maintenance advice | No | Rewarding negligence = encourages more negligence |
| Expensive fix (over £500) | No (unless very long-term customer) | Can't absorb large costs for non-warranty work; business survival matters |
Decision framework: Fix free if (customer lifetime value + reputation protection) > (cost to fix + precedent risk). Otherwise, charge.
Warranty Terms That Protect You (Written Documentation)
Your warranty document should include these protective clauses:
Get customer to sign warranty terms at completion. SMS/email confirmation works: "I confirm I've received warranty document and understand the terms."
The Verdict: Investigate First, Decide Second
Most warranty claims that "aren't your fault" are grey-area situations requiring investigation—not instant rejection.
Here's your warranty claim system:
- 1. Investigate thoroughly – Site inspection, root cause analysis, evidence collection before you respond
- 2. Distinguish fault types – Installation fault = your warranty; misuse/wear/external = customer pays
- 3. Help with manufacturer claims – Product defect = you do labour free, customer claims part warranty
- 4. Use clear scripts – Explain why not covered, offer paid solution, don't just say "no"
- 5. Fix strategically for goodwill – Long-term customers + small fixes = relationship investment
- 6. Document warranty terms – Written exclusions, maintenance requirements, claim process
The tradespeople who lose money on warranties are the ones who fix everything for free. The ones who stay profitable? They investigate, document, and only cover genuine workmanship faults.
Stand behind your work. But don't pay for customer negligence or manufacturer defects.