Glow-worm Majorca Boiler Guide

The Glow-worm Majorca range was built to last, but most models are now more than thirty-five years old. Even with careful servicing, time and heat take their toll. Seals dry out, metals corrode, and key components are no longer available. Below are the most frequent issues across the Majorca 40, 50, 60, 70, and 80 models, explaining what causes them, how they are diagnosed, and what homeowners can expect when these problems appear.

Boiler not firing up
A Majorca that refuses to fire up is a familiar sight for heating engineers. You may hear the click of ignition or see the pilot flame flicker, but the burner will not light fully. This usually happens on the Majorca 60 and 80 models, which rely on mechanical gas valves that stiffen or seize after decades of use. Other causes include a worn thermocouple, faulty gas valve coil, or low gas pressure. An engineer can check voltage and continuity through the ignition circuit, but because original components were discontinued years ago, any repair depends on finding compatible reconditioned parts.

Pilot light keeps going out
The Majorca 40 and 50 use a permanent pilot light that should stay lit at all times. If it keeps going out, the thermocouple or pilot jet is often to blame. The thermocouple senses flame presence and cuts gas flow if the pilot goes out, but after years of constant heat exposure it becomes unreliable. Sometimes, dust or soot clogs the pilot assembly, starving it of gas. Cleaning may restore the flame temporarily, but when relighting becomes a daily task it is a clear sign the boiler has reached the end of its useful life.

Overheating and constant tripping
Overheating occurs when heat cannot move freely through the system. On the Majorca 60 and 70, this is common due to sludge or scale buildup inside the cast-iron heat exchanger. The boiler may roar, pop, or make kettling noises as water boils in pockets. Mechanical thermostats, found across the full Majorca range, also lose calibration over time and fail to shut off at the correct temperature. Engineers can flush the system and fit a temporary temperature cut-out, but both fixes are short-lived once scale has taken hold.

No heating or hot water
When both heating and hot water stop working, it is usually a circulation or pump issue. Older systems with Majorca 50 or 60 boilers often relied on original bronze pumps that seize after long periods of inactivity. A blocked feed or return pipe can also cause the same symptoms. Engineers sometimes try to free a stuck pump shaft, but if corrosion is advanced, the problem quickly returns. At this age, poor water quality and sludge mean breakdowns tend to repeat even after repair.

Leaks and corrosion
Leaks are one of the most serious and common problems with the Majorca 70 and 80 models, particularly around the pump connections and heat exchanger seals. Continuous heating and cooling cycles cause expansion and contraction, eventually creating hairline cracks in the metal. Rust or greenish stains beneath the boiler casing are early warning signs. Once the heat exchanger starts leaking, replacement is not practical because parts are obsolete. Continued use also risks damaging electrical components, which can lead to complete failure.

Kettling and loud noises
A boiling or rumbling sound during operation is caused by limescale buildup inside the heat exchanger. The Majorca 40 and 60 are particularly prone to this if they have been running on hard water without treatment. Scale restricts water flow, creating localised hot spots that cause water to vaporise and bubble violently. An engineer can use a chemical descaler or power flush, but if the internal walls are heavily scaled, noise and inefficiency will soon return.

Low pressure and cold radiators
Some Majorca systems lose pressure frequently or heat radiators unevenly. This usually means there is a slow leak or the expansion vessel is no longer working. The expansion tanks fitted in older setups were often external and now suffer from internal rusting. Engineers can recharge or replace them, but constant pressure loss usually points to system corrosion. On a 1980s-era boiler, that is often the beginning of a full system decline rather than an isolated fault.

Flue and ventilation problems
The open-flued versions of the Majorca 40 and 50 depend on room air for combustion, which makes ventilation crucial. Over time, flues can become partially blocked by dust, soot, or nesting debris. This can cause poor combustion, visible soot marks, or yellow flames, all signs of incomplete burning and potential carbon monoxide risk. Balanced-flue versions of the Majorca 60 and 70 are safer but still need clear air pathways. Any sign of staining or fumes should be treated as urgent, and the boiler should be switched off immediately until checked by a Gas Safe engineer.

Fan failure (balanced-flue models)
Later models, like the Majorca 70BF and 80BF, use a small fan to move exhaust gases through the flue. After decades of operation, bearings dry out and motors seize. You might hear a faint hum or nothing at all when the boiler tries to start. Because genuine fans are no longer produced, engineers sometimes fit adapted alternatives, but performance and safety cannot be guaranteed.

Soot and incomplete combustion
If you see dark marks around the flue outlet or casing, it is often due to incomplete combustion. This happens when the burner ports are partially blocked or the gas-air mix is off balance. It is more common on open-flued Majorca 40 models that rely on natural room air. These signs should never be ignored because incomplete combustion can lead to dangerous carbon monoxide buildup.

Parts discontinued
The biggest limitation across the entire Majorca range is the lack of replacement parts. Key components such as gas valves, ignition controls, and thermostats were discontinued long ago. While some refurbished spares exist, they are costly and unreliable. Even when an engineer can make a repair, it often extends the boiler’s life by only a few months before another fault occurs.

Summary
The Glow-worm Majorca range has served far beyond its intended lifespan. Repeated ignition faults, corrosion, and poor efficiency are inevitable after nearly four decades of service. While some repairs are possible, they are rarely cost-effective. Replacing the boiler with a modern A-rated model is usually the only realistic long-term solution, improving energy efficiency, safety, and comfort throughout the home.