Can Plumbers Service Boilers? What You Need to Know

When your home’s heating stops working, the first question is often, "Do plumbers handle boilers?" The short answer is yes, but there are important nuances. In this guide we’ll break down what a plumber actually does, how a boiler works, and when you should call a plumber versus a specialist heating engineer. By the end you’ll know exactly who to call for a safe, effective boiler repair and what to expect.

What a Plumber Does

A plumber is a tradesperson trained in installing, maintaining, and fixing water supply and drainage systems. They work with copper, PVC, and PEX pipes, pressure‑tested valves, and fixtures such as sinks, toilets, and showers. In New Zealand, plumbers must be licensed under the Building Act and often hold a Class 2 or Class 4 gas licence, which allows them to work on gas‑fed appliances, including some boiler components.

Understanding Boilers and Heating Systems

A boiler is the heart of a domestic heating system. It heats water that circulates through radiators, underfloor pipes, or a hot‑water cylinder, providing both space heating and domestic hot water. Modern boilers are either combi (combined) units that deliver hot water on demand, or system/heat‑only models that rely on a separate cylinder. Key parts include the heat exchanger, pump, gas valve, and control board.

Where Plumbing and Boiler Work Overlap

Because plumbing and boiler work share pipework, many issues sit at the intersection of the two trades. Common overlap tasks include:

• Replacing or fixing leaking supply or return pipes.
• Installing or servicing a hot‑water cylinder.
• Pressure‑relief valve checks.
• Diagnosing low pressure caused by a faulty pipe or valve.

These jobs are well within a licensed plumber’s skill set, especially if they hold a gas licence.

When to Call a Plumber vs. a Heating Engineer

Not every boiler issue falls under a plumber’s responsibilities. Here’s a quick decision guide:

If a problem involves gas combustion, flue checks, or electronic diagnostics, a qualified heating engineer (sometimes called a boiler technician) is the right call. Plumbers excel at anything that stays within the water‑circuit realm.

Common Boiler Issues Plumbers Can Fix

Below are typical faults where a plumber’s expertise shines:

1. Low pressure: Often caused by a leak in the expansion vessel or a faulty pressure‑reducing valve. A plumber can replace the valve and re‑pressurise the system.
2. Leaking pipework: A cracked pipe, corroded joint, or loose connection can lead to water loss and reduced efficiency. Plumbers locate the source and fit new copper or PEX sections.
3. Faulty hot‑water cylinder: If the cylinder drips or the thermostat fails, a plumber can swap the unit or replace the thermostat.
4. Air in the system: Air pockets cause banging noises. Plumbers bleed radiators and, if needed, install air‑vent valves.
5. Pressure‑relief valve (PRV) issues: A stuck PRV can cause over‑pressurisation. Plumbers replace PRVs and test them according to AS/NZS 5601 standards.

These fixes usually don’t require the deeper combustion analysis that heating engineers perform, keeping costs lower for homeowners.

Limitations: Safety and Certification

Even a licensed plumber must respect safe‑working boundaries. Key limitations include:

• Gas safety certificate -Only a gas‑licensed tradesperson can issue this document after a boiler installation or major gas work.
• Complex combustion problems such as incomplete burning, carbon monoxide leaks, or flue blockages require a heating engineer with a specialist combustion test kit.
• Electronic control board failures often need a technician familiar with boiler firmware and diagnostic codes.

Attempting these tasks without the right credentials can void insurance, breach regulations, and put your family at risk.

Homeowner Checklist Before Calling a Tradesperson

Use this short checklist to decide who to call and what information to gather:

• Identify the symptom: pressure loss, leak, no hot water, odd noises, or error codes.
• Check the boiler’s make and model (usually on a data plate inside the casing).
• Locate any visible water leaks and note the exact location.
• Record the current pressure reading on the gauge.
• Determine if the problem involves gas‑related components (valve, burner, flue).
• Have your gas licence number handy if you’re calling a plumber for gas work.

Providing these details speeds up diagnosis and ensures the right professional arrives.

Bottom Line: Who Should Do Your Boiler Work?

In most everyday scenarios-leaks, pressure drops, cylinder swaps-a qualified plumber with a gas licence can handle the job efficiently and safely. For anything that touches combustion, flues, or advanced electronic controls, bring in a certified heating engineer. Knowing the difference saves you time, money, and potential safety headaches.