Common Keston Boiler Problems and Repairs

There’s never a good time to experience problems with your Keston boiler, but you might be surprised to learn that some issues are quite simple to sort without the need to contact a qualified engineer. Some problems are more common than others and, fortunately, the majority of typical faults can be fairly easy to diagnose. Having said that, many of the issues that can occur will require immediate attention and the specialised knowledge and expertise of a Gas Safe registered engineer. 

If you’ve got heating or boiler issues, below is a list of the most common Keston boiler problems and repairs, as well as advice on what you should do next. 

1. Boiler won’t ignite

Many faults could stop your Keston boiler from igniting, such as a frozen condensate pipe, a faulty gas valve, no gas supply, a blocked flue or a fault with the fan. If you try to ignite the boiler 5 times and it fails, a fault code should appear on the control panel. 

What to do next: You can check to see if there’s an issue with the gas supply by testing your other gas appliances. If your other appliances are working properly and your boiler’s condensate pipe is located outdoors, you’ll need to go outside to see if it’s frozen. You can thaw the pipe with some warm water or a hot water bottle, but you mustn’t ever pour boiling water onto the pipe. If the pipe isn’t frozen, the fault might be caused by a faulty gas valve or broken fan, so you’ll need to call in a Gas Safe registered engineer to check both and fix the problem. 

2. Boiler pressure is too low

This is a fairly common problem, often caused by a water leak. Having said that, you may just need to top up the pressure to get it back to the correct level. The boiler pressure should never be below 1 bar, and you can find the correct pressure level for your Keston boiler in the boiler manual. 

What to do next: Before you do anything else, take a look at your boiler, any pipework and your radiators to see if you can find a leak. If you spot a leak, you won’t be able to fix this yourself, so you’ll need to contact a Gas Safe registered engineer right away. But if you can’t locate a leak anywhere, then you can try and top up the boiler’s pressure using the external filling loop and by following the instructions in the manual that came with your boiler. If you don’t feel confident doing this yourself, get a qualified engineer to do it for you. 

3. Boiler pressure is too high

If you’ve checked the needle reading on your Keston boiler’s pressure gauge and the reading is above 1.5 bar, then the boiler pressure is too high. This is something that needs to be sorted quickly because high boiler pressure can put a strain on your boiler and lead to expensive repairs. 

What to do next: You can try and drain some water from your system by simply bleeding your radiators using a bleed key. Try and get the pressure to 1.3 bar, and don’t worry too much if you drain too much water from the system as you can top up the water afterwards. If bleeding your radiators doesn’t help to decrease the boiler pressure, you should ask a Gas Safe registered engineer to inspect your Keston boiler to find the culprit and a solution.  

4. No hot water or no heating

If you don’t have any hot water or heating, it could be that there’s a problem with the diverter valve in your Keston boiler. A faulty diverter valve is a common issue, particularly with an ageing Keston boiler. The diverter valve is an important part of your system because it determines when you get hot water to your taps and radiators. When the diverter valve becomes stuck or damaged, it may only allow water to your taps but stop the water entering your radiators or block off the water to your taps and only allow the heated water to go into the radiators. 

What to do next: Unfortunately, there’s nothing you can do if the diverter valve is stuck or faulty other than get in touch with a Gas Safe registered engineer. Your engineer will be able to see if the diverter valve is the issue, and then repair or replace it. If the diverter valve isn’t to blame, your engineer can inspect your boiler and check over all the internal parts to determine the cause of your hot water or heating problem.