Troubleshooting Glow Worm Boilers: Common Problems and How To Fix Them

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Last updated: October 31, 2023

Choosing the right boiler for your home is a big deal. If you’re not careful, it can become an expensive mistake that ends up costing you more in the long run. There are tons of boiler models out there from all different manufacturers and they’re often confusing to understand for both homeowners and HVAC professionals alike. In this article, we’ll focus on Glow Worm Boilers and how to troubleshoot some of the most common problems of this brand.

Glow Worm Boilers are a great option for heating your home. They’re especially popular because they provide a variety of dependable and easy-to-install boilers that are both cheap and highly recommended by professional engineers. However, there is still the chance that something could go wrong with them; this article will provide information on common problems and how to fix them.

Why Choose Glow Worm Boilers?

Glow Worm Boilers are British-made boiler systems that have been designed to be efficient and low-maintenance. They come in a variety of models, including combi boilers, system boilers, heat only boilers and even solar thermal systems.

Glow Worm Boilers are one of the most reliable boiler brands on the market. They’re often recommended by professional engineers for their reliability, durability and easy installation. They’re so popular that they account for almost half of all new boilers installed in the UK!

The Benefits of Using Glow Worm Boilers

There are many reasons why you should consider using Glow Worm Boilers in your home. Some of the benefits include:

  • Efficient and low-maintenance design that is both British-made and reliable
  • A variety of models to choose from, including combi boilers, system boilers, heat only boilers and solar thermal systems
  • Highly recommended by professional engineers
  • They’re one of the most reliable boiler brands on the market
  • The price is often cheaper than other boiler brands
  • They’re very easy and quick to install, which leads to less downtime for the homeowner

Now that we have covered up the reason why you should choose Glow Worm Boilers, let us move on to the most common problems that have been reported with this brand.

The Most Common Problems With Glow Worm Boilers

Although Glow Worm Boilers are some of the most reliable boilers on the market, there is still a chance that something could go wrong. In this section, we’ll take a look at some of the most common problems with these boilers and provide information on how to fix them.

#1. No heating or hot water is coming from the boiler

One of the most common problems with Glow Worm Boilers is that there’s no heating or hot water. This could be due to a variety of reasons, such as a broken thermostat, valves failure, low water levels, a blocked flue or an issue with the pump.

How To Fix: If you’re experiencing this problem, first check to make sure that all of the valves are turned on. Next, check to see if there is a problem with the thermostat by testing it in another room. Begin by determining whether the boiler pressure is too low (below 1 bar) and whether the temperature is high enough for the heating to come on. In addition to these, make sure you have adequate credit if you’re on a prepayment meter. If that’s not the issue, then you’ll need to check the pump and the flue for blockages. If you’re still having problems after checking these things, then you may need to call a professional to get it fixed.

#2. Low Boiler Pressure

Low boiler pressure is another common problem that people experience with Glow Worm Boilers. This can be caused by a variety of things, such as sediment build-up in the boiler, a blocked flue or a fault in the pump.

If the pressure gauge on your Glow-worm boiler reads anything below 1 bar, there may be a problem that will cause your central heating system to function poorly. Although boilers lose pressure over time, a rapid drop might mean there’s an issue with the system, most likely a leak. F22 or a 108 error code is the most frequent symptom of this problem.

How To Fix: If you detect a leak in your system, turn off the water supply to prevent further harm and contact a professional. However, if the pressure drop was gradual, follow these simple measures to resupply the system. Fill the system with water through the external filling loop until the pressure gauge pointer is in the green zone between 1 and 2 bars. When the pointer reaches 2 bar, the boiler will be at high pressure, which can cause harm. If you’re not comfortable or safe repressurizing the system yourself, get help from a professional.

#3. Frozen condensate pipe

Sometimes, people experience frozen condensate pipes with Glow Worm Boilers. If you notice that the condensate pipe is frozen, then this means that there’s not enough heat in your system to get it up to temperature. A condensate pipe on a condensing boiler removes acidic water from waste gas. This is generally poured outside, where it might freeze in the cold months. When the condensate pipe freezes and gets clogged, you may hear gurgling noises, and the system may shut down to prevent further damage. The following faults were detected: F1, F28, F29, and F4. These fault digits indicate a flame or boiler ignition issue.

How To Fix: Unblocking a frozen condensate pipe can be done without the assistance of a professional. To thaw the ice within, pour hot water on top of the pipe not directly to the pipe because hot water will melt the plastic pipe. If trapped debris is to blame for the blockage, you should contact a specialist to clean and rinse the tube.

#4. The boiler has been locked out.

Sometimes, your Glow Worm Boiler may lockout and stop working. A boiler lockout is a safety procedure that is performed to safeguard the components of the boiler from further damage and for the protection of personnel. Despite the many causes and fault codes for boiler lockouts, the most frequent is F83. When this code appears on a boiler, it indicates that hot water isn’t heating properly when it fires up. When the boiler starts up, the thermistors are usually designed to sense a significant temperature difference in the return and flow of water. In this situation, either there isn’t enough of a difference or no distinction is being made.

How to fix: A boiler technician will first check the sensors on the flow pipe, return pipe, and burner for this problem. Even if everything else is fine, if the PCB isn’t receiving accurate readings from any of these components, the boiler will lock out. If at least one of the above boiler pieces needs to be replaced, an engineer will have to fix the boiler.

#5. There is boiling water in the boiler, but no hot water.

Another common problem that people experience with Glow Worm Boilers is that there’s boiling water in the boiler, but no hot water coming from the shower or faucets. Typically this indicates an issue with the diverter valve. The diverter valve opens and shuts to allow for the transfer of heat between the boiler and hot water supply. Because it is a moving part of a boiler, it is prone to failure.

How to fix: In this situation, a professional should be called to repair or replace the diverter valve. It is much more cost-effective and practical to replace a damaged portion of the diverter valve than it is to attempt to mend its damaged portion.

#6. There is a gas supply problem.

Occasionally, a Glow Worm Boiler will experience a gas supply problem. This typically occurs after the boiler has been installed and started up for the first time, although it can happen to boilers that have already been in use. When the F28 fault code appears, the boiler is usually disabled, making it secure. The fault code indicates that there may be a leak in the system. Don’t try to reset the boiler in this situation since there could be a leak. The F28 fault code will cause the pressure relief valve to open, releasing gas into your plenum.

How to fix: A thorough inspection by a professional may discover other issues with the building’s gas system that are causing the F28 fault code. The engineer will check all possible causes of the F28 fault code. The inspection process usually involves testing all relevant components and connections by carrying out an energy audit. If the problem is within the gas valve, the engineer may need to replace it. The expense of replacement can range from £250 to £300.

These are just a few of the most common problems people experience with Glow Worm Boilers. If you are experiencing any of these issues, be sure to call a professional for help. They will be able to properly diagnose the problem and fix it on time so that you can get back to using your boiler as normal.

For more information about faults for popular boiler brands check out out guides for BaxiWorcester and Vaillant boilers.


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