A technician installs a 24,000 BTU Daikin unit at a shophouse in Nonthaburi. Five weeks later, the shop owner calls: “It’s not cooling. Come fix it — this is still under warranty.” The technician who answers says yes, because that feels like the right answer — and because nobody ever told him what the warranty actually covers. He drives out, checks the unit, and finds the indoor drain pan cracked and flooding the PCB board. Did it crack because of how the unit was installed? Or because something hit it after handover?

One answer means your business absorbs a repair running 1,500–3,000 baht in parts alone. The other means a hard conversation with a customer who is already frustrated. Neither is easy without a written policy and a record of the original installation. Most Thai install businesses handle warranty calls entirely by gut feel: go out, look at the problem, decide in the moment. Over time, that approach trains certain customers to call back for anything and expect the visit to cost them nothing.

What Does “Warranty” Cover on an Installation Job?

There are two separate warranties on any installation project, and conflating them is the source of most disputes.

Workmanship warranty covers defects in the installation itself: a refrigerant pipe joint that was not brazed correctly, a bracket not secured to a concrete wall, a drain line sloped the wrong direction and now overflowing into the ceiling cavity. This is entirely the installer’s responsibility. Typical coverage for Thai installation crews is 30–90 days from the installation date, depending on the business and job type.

Equipment warranty covers defects in the unit itself — compressor failure, PCB faults, fan motor burnout under normal use. This is the manufacturer’s responsibility. Daikin’s residential compressor warranty in Thailand is five years; Mitsubishi Heavy covers three years on most models; Carrier and Panasonic vary by product line and registration. When equipment fails within the manufacturer’s period, the installer’s role is to help the customer make the claim — not to absorb the manufacturer’s defect cost.

Most customers hear “warranty” as a single undifferentiated promise: everything, free, indefinitely. Without a written policy given to them at handover, that expectation hardens into fact and becomes very difficult to walk back months later.

Why Most Warranty Calls Turn Into Disputes

The problem usually starts at the end of the installation, not during the callback.

When a technician finishes a job and leaves without giving the customer a written record, the customer has nothing to reference when something goes wrong. Six weeks later, when the unit starts dripping or the remote loses its pairing, both sides are working from memory — and memory is a poor foundation for any dispute involving a 15,000-baht piece of equipment.

Without a documented handover:

There is no baseline showing what condition the equipment was in when you left
You cannot tell whether the fault is in the original work or in something that happened afterward
The technician sent on the callback arrives with no installation context, no equipment serial number, no photos

A documented handover does not prevent every callback. It does prevent most disputes.

What Should a Written Warranty Policy Actually Say?

A warranty policy for a small installation business does not need to be a long document. A short paragraph on the job completion form covers the practical cases:

Workmanship: Installation labor and materials are warranted against defects for [30/60/90] days from the installation date.
Equipment: Product warranty follows the manufacturer’s published terms. We will assist with manufacturer warranty claims during the coverage period.
Not covered: Physical damage from power surges, pest infestation (rat-damaged wiring is common in Thai commercial buildings), unauthorized modifications, physical impact, or faults reported after the workmanship warranty period has elapsed.

Write this on the job completion form. Have the customer sign it. Send them a copy via LINE or PDF at the end of the job. This step takes two minutes and prevents the conversation — eighteen months after installation — where a customer insists a repair is free because they heard the word “warranty” once.

The Documentation That Makes a Warranty Call Simple

Four things from the original installation record resolve most warranty calls without a dispute:

Equipment details: brand, model number, and serial number of every unit installed
Installation date and the technician who completed the work
Photos from installation day: the unit in position, the refrigerant pressure gauge reading, the completed drain outlet, before-and-after shots of the installation area
Customer signature confirming the system was running correctly at handover

When these exist and are retrievable, a warranty callback closes in one site visit. When they do not exist, the same callback turns into a negotiation with no objective reference point on either side.

How Should You Respond When a Customer Calls About a Warranty Issue?

The first phone call is for gathering information, not making commitments. Do not agree to a free repair before seeing the fault.

A practical first response: “Thank you for letting us know. Can you describe what you’re seeing? We’ll send a technician out to take a look, and we’ll confirm from our installation record what falls within warranty coverage once we’ve assessed the fault on site.”

This acknowledges the complaint, commits to action, and ties the coverage decision to the documentation — not to the customer’s expectation. At the site visit, the technician brings the original job record and identifies the fault as one of three categories: workmanship, manufacturer defect, or external cause. That categorisation, backed by the record and the installation photos, determines the response.

What Gets Billed and What Doesn’t?

Workmanship fault within your warranty period: No charge. Correct the issue at your expense. This is the only callback scenario where the cost falls on your business.

Equipment failure within the manufacturer’s warranty period: The part is covered by the manufacturer. Your labor for the visit is a judgment call. For customers on active MA contracts or with a significant install history with your business, absorbing one labor call builds long-term loyalty worth far more than a 400–600 baht service fee. For a one-time customer on a small job, that fee is reasonable and easy to explain with the documentation in hand.

External cause — surge, pest damage, physical impact: Not a warranty item. State that clearly before starting any repair work, and get verbal confirmation before touching anything: “The damage appears to come from [cause], which is outside the warranty scope. The repair cost is approximately [amount] — shall we proceed?” Getting agreement before starting prevents a second dispute over an unexpected bill.

After the workmanship warranty period: Standard call-out rate applies. The signed completion record shows the installation date and the warranty terms. The conversation takes thirty seconds.

FAQ

What if a customer insists it is our fault even though the warranty period has passed?

Walk through the original installation record together: the installation date, the warranty terms the customer signed, and photos showing the equipment state at handover. This gives you a documented baseline that is difficult to argue against. If the customer remains frustrated, offering a modest goodwill discount on the repair — not a free visit — usually resolves the tension without setting a precedent that every future callback is free.

How long should installation records be kept?

For the full equipment warranty period plus twelve months. A five-year compressor warranty means keeping the installation record for six years from the installation date. Solar inverter and CCTV system records should be held for the manufacturer’s full warranty term plus one year. Digital records in a job management system cost nothing to retain and occupy no physical space — there is no practical reason to delete them.

If a subcontractor installed the system, who covers the warranty?

The business the customer contracted with is responsible — typically your business, not the subcontractor. Your subcontractor agreements should reflect this: the sub is liable to you for workmanship faults within a defined period, and you are liable to the customer. This is why subcontractor jobs need the same documentation quality as in-house work: equipment serial numbers, installation photos, and a customer signature at handover.

An OnSiteQ work order captures equipment brand, model, and serial number, the technician on site, job photos, and a customer signature in one record that stays attached to the customer’s account. When a warranty call comes in six weeks later, the record is already there — and the conversation is short.

Handling Warranty Calls After Installation Jobs