Glow-Worm Boiler F.89 Fault Code
The Glow-Worm fault code F.89 relates to a pump issue and here we have Q & A or require an engineer for an emergency boiler repair.
The Glow-Worm Boiler Fault Code F.89 Error Common Q & A
Just below, we have a list of common questions relating to the F.89 fault code on the Glow-Worm Boiler.
- What does the F.89 fault code mean on my Glow-Worm boiler?
- Will I need a new boiler if there is an issue with the heating pump?
- Is my boiler dangerous if it’s showing the F.89 fault code?
- What problems can occur with the pump?
- How does the wiring to the pump become damaged, and the connections loose?
- How are blockages caused in a boiler’s pump?
- If my heating pump is blocked full of heating sludge, can it be repaired?
- My boiler engineer thinks I need a new heating pump, how much is this likely to cost?
- Is there a way to stop heating sludge causing the F.89 fault code to occur again in the future?
- How can an airlock be removed from the pump?
- How will my heating engineer know if the shaft or bearings are damaged on my heating pump?
- Why does the pump’s shaft have to be installed horizontally?
- If my pump’s speed setting isn’t correct, can this be fixed to clear the F.89 fault code on my Glow-Worm boiler?
- Is there anything besides the pump that could be causing the F.89 fault code to be displayed on my Glow-Worm boiler?
- How much will it cost if I need to replace the PCB on my Glow-Worm boiler?
What does the F.89 fault code mean on my Glow-Worm boiler
When your Glow-Worm boiler develops a problem, the printed circuit board (PCB) will display an error code on the display panel. This makes it easier for a Gas Safe engineer to find and fix the problem.
In this case, the F.89 relates to a pump issue.
Will I need a new boiler if there is an issue with the heating pump
If the rest of your boiler’s components are in good condition, it’s unlikely that you’ll need a replacement boiler.
Depending on the exact problem, the pump can using be adjusted, repaired, or replaced, which is much cheaper than replacing your boiler.
Is my boiler dangerous if it’s showing the F.89 fault code
We’d not expect your boiler to be dangerous if the F.89 fault code is being displayed. However, there’s a good chance that the boiler isn’t working correctly. For instance, you might be having trouble getting hot water and radiators up to temperature.
If in doubt, you should always call a Gas Safe boiler engineer. Only those with Gas Safe accreditation are qualified to work on gas appliances.
What problems can occur with the pump
The pump on your Glow-Worm boiler goes through lots of abuse. Over the years, it can develop a range of faults including:
- Damaged wiring or loose connections
- Blockages
- Air locks
- Damaged shaft or bearings
But, the cause of the F.89 fault code being displayed could also be related to:
- Incorrect installation
- Incorrect speed setting
How does the wiring to the pump become damaged, and the connections loose
The wiring to your pump is fragile. Although old age can cause a circuit to fail, it’s much more likely to be water damage.
Boiler components (including the pump) are prone to leaking. When they do, moisture from the leak settles on electrical components, wires and connections. This can cause connections and/or wiring to burn out, and parts like the pump to fail.
If your boiler engineer suspects that it’s a leak that has caused the damage in the first place, they’ll first have to find and fix the leak, before repairing the wires and connections.
Likewise, connections can come loose over time, thanks to boiler vibrations. But, if you’ve noticed that your boiler has been incredibly noisy recently, it’s likely a part has failed. This could be anything from fan’s shaft to the pump’s bearings. Like the leak, the problem causing excessive vibrations will need to be found and fixed, to stop this from happening again.
How are blockages caused in a boiler’s pump
The most common reason that a pump gets blocked, is due to central heating sludge.
Central heating sludge is a combination of rust from towel rails, radiators, and the inside of copper pipework. As the rust breaks off, it starts flowing around the heating system. When it does, it can cause all kinds of problems.
As it flows around the heating system, it can get lodged just about anywhere. That’s going to lead to problems like radiators not heating up correctly, not to mention the pump not functioning correctly.
If my heating pump is blocked full of heating sludge, can it be repaired
If the pump’s shaft and bearings are in good condition, and it’s not leaking, the unit is worth repairing.
The repair is quick and easy. Your boiler repair engineer will remove the pump and clean it out. They’ll then refit the pump, making sure that the pump’s shaft is horizontal.
My boiler engineer thinks I need a new heating pump, how much is this likely to cost
If your pump can’t be repaired, a replacement is going to be needed. Assuming they fit a replacement pump from a leading brand such as Grundfos, you should expect to pay somewhere in the region of £250.
That price is going to include all parts and labour, and the job should take around 1 working day to complete.
Is there a way to stop heating sludge causing the F.89 fault code to occur again in the future
There are several precautionary measures you can implement to make sure that you don’t suffer this problem again.
The first, is to ask your boiler repair engineer to run a “hot flush”. They’ll use chemicals to flush out existing heating sludge in your heating system.
Once they’ve done that, they’ll top up your boiler, and add central heating inhibitor. It’s this inhibitor that helps to break down any heating sludge that presents itself in the future.
Then, they’ll fit what’s known as a magnetic system filter. This catches the sludge, that the central heating inhibitor has broken down.
And, as a final precaution for those living in a hard water area, there are scale reducing filters. This stops limescale build-up in radiators, as well as expensive components like the heat exchanger.
How can an airlock be removed from the pump
An airlock can be removed from a pump quickly and easily. If you have airlocks in your heating pump, you might have noticed the pump making banging noises recently, as well as the boiler being intermittent when it comes to its ability to provide hot water and heating.
But, you shouldn’t work on a gas appliance. Instead, call a Gas Safe engineer. They’ll be able to bleed the heating pump via the bleed screw. Once they’ve done this, they’ll reset the boiler, which should clear the F.89 fault code.
How will my heating engineer know if the shaft or bearings are damaged on my heating pump
If your heating pump’s bearings or shaft is damaged, it’s going to struggle to circulate water. It will be immediately obvious both visually and it will make a grinding noise.
Although the pump’s shaft and bearings can be replaced, it’s most likely your repair company will suggest a replacement pump, due to the cost of the repair. A new pump will come with a long manufacturer’s warranty.
Most importantly, when they replace the pump, the engineer is going to make sure that the pump’s shaft is horizontal. It’s most likely that the pump wasn’t fitted 100% horizontal in the first place, and this has led to the shaft and bearings wearing out prematurely.
Why does the pump’s shaft have to be installed horizontally
If your pump’s shaft or bearings are damaged, it’s likely incorrect installation is the cause.
The pump’s shaft needs to be installed horizontally, so the shaft and the bearings aren’t put under any additional pressure. The pump is already one of the hardest working components in the boiler, and having additional pressure put on its internal parts, is only going to make it wear out faster.
If my pump’s speed setting isn’t correct, can this be fixed to clear the F.89 fault code on my Glow-Worm boiler
Many modern pumps have three speed settings to choose from. That helps to make the pumps universal. They can be used in a small property on a low-speed setting, and a large property on a high-speed setting.
If you live in a large property and the pump is set on it’s lowest (and slowest) setting, it’s unlikely to be circulating water quick enough. By the time water reaches taps, radiators and towel rails, it’s cooled down too much.
Your boiler engineer will be able to adjust the speed setting on your pump. After they’ve done this, they’ll reset the boiler. The PCB should recognise the adjustment and the fault code will be cleared.
Is there anything besides the pump that could be causing the F.89 fault code to be displayed on my Glow-Worm boiler
If your boiler engineer is having problems diagnosing the fault, they’ll need to start testing the PCB.
The PCB is the most important part of your boiler. It gives and receives signals to and from sensors, as well as components like the pump, heat exchanger, and fan.
If the PCB isn’t working correctly, then it’s unlikely other components will be either (including the pump).
Your boiler engineer will be able to test the pump and PCB for power using a multi-meter. If one component isn’t getting power, it’s likely it needs replacing, or the wiring/connections need to be repaired/re-secured.
How much will it cost if I need to replace the PCB on my Glow-Worm boiler
Some parts on Glow-Worm boilers are cheap to replace. However, the PCB isn’t one of them. Typically, a PCB replacement is going to cost in the region of £500.
For this reason, we’d advise having your boiler engineer inspect the rest of the boiler. If other components are showing signs they could fail soon, it makes sense to replace the boiler, rather spending hundreds of pounds on repairs.
Other Glow Worm boiler issues
For more boiler issues regarding the Glow Worm then please visit the Glow Worm Boiler Problems And Cures page.