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Some common ATAG boiler problems can be resolved without even having to call an engineer out but if an engineer is needed, (and if in doubt always get in touch with an engineer) you can get a free boiler repair quote with our service.
What are the most common ATAG boiler problems?
| Top 5 ATAG Boiler Problems | ATAG Error / Fault Code |
| System igniting without being asked for | – |
| Low boiler pressure | 118 |
| No heating or hot water | – |
| Radiators not heating up | – |
| Heating but no hot water | – |
1. System coming on without being asked for
Digital wireless room stats could lead to your ATAG boiler turning on unexpectedly – potentially wasting energy when you’ve not made a call for heating or hot water.
How to stop the boiler randomly turning on?
If this happens, double check that the minimum room temperature setting is fairly low (8°C to 12 °C) because if it’s too high then when the room temperature falls below that temperature the wireless room stat will alert the boiler and heat the house up.
2. Low boiler pressure (error code 118)
This error code means that the pressure is less than 1 bar or pump pressure increase is too low (no pump detection).
Increasing low boiler pressure
3. No heating or hot water
Possible causes can be broken diaphragms and airlocks, issues with the thermostat, low water levels or failure of motorised valves. It’s a good idea to check if an issue with boiler pressure or your thermostat are causing the issue.
If you think that your boiler needs a new part then you’ll need to get a Gas Safe registered engineer on the case. They’ll be able to thoroughly diagnose the problem and replace any broken parts where necessary.
4. Radiators not heating up
If your radiators aren’t heating up or are only heating up at the bottom there could be air trapped in the system. When there’s too much air, it can cause blockages, which will prevent the hot water from circulating around the radiators. To get the radiators heating up again, they may need to be bled.
How to bleed radiators?
Before getting started with bleeding the radiators, make sure the central heating is turned off. Never bleed the radiators while the heating is on.
Once the heating is off and the system has had the chance to call down. Don’t hesitate to contact a Gas Safe registered engineer to take care of this if you don’t feel comfortable.
5. Heating but no hot water
ATAG combi boilers send hot water instantly to the radiators or hot water tap depending on which you need at the time. A diverter valve directs the water to the appropriate outlet but from time to time, especially on older boilers, they can get stuck, meaning that even though you’re turning the hot tap on, the radiators are getting warm.
Fixing a diverter valve
A diverter valve isn’t something you can fix yourself, you’ll need a professional heating engineer to either repair the diverter valve or replace it, depending on its condition.
Which ATAG Boiler Problems Need an Engineer?
We’ve put together a list of the most common boiler symptoms, to give you an idea of what they might mean and whether you’ll be able to fix it yourself or need an engineer.
| Problem | Possible Cause | Do you need an engineer? |
| No heat or hot water | Broken diaphragms and airlocks, failure of motorised valves, issues with the thermostat or low water levels | Yes |
| Leaking and dripping | Most common cause is a broken internal component but it will depend where the water is leaking from | Yes |
| Banging, whistling or gurgling noises | A common cause is air in the system, alternatively it could be that the water pressure is too low or it’s kettling | Yes |
| Pilot light goes out | Could be a broken thermocouple which is stopping the gas supply | Yes |
| Losing pressure | Could be a water leak in the system, the pressure relief valve needs replacing or due to recently bleeding radiators | No, unless there’s a leak |
| Frozen condensate pipe | Your boiler will often display a fault code or warning notification | Yes |
| Thermostat issues | Thermostat may be turned off or not set to the correct settings (time etc.) | Consider replacing |
| Kettling | Limescale or sludge building up on your boiler’s heat exchanger | Yes |
| Radiators not getting hot | You will need to bleed the radiators which doesn’t require an engineer unless you don’t feel like carrying out the task yourself. | Yes |
| Boiler keeps switching itself off | Could be low water pressure, a problem with the thermostat or a lack of water flow due to a closed valve, air or the pump not circulating the water in the system properly | Yes |
ATAG Boiler Error Codes
When your ATAG boiler has an error, you’ll see an error symbol appear on the screen accompanied by a code, which is usually a 2-3 digit number.
Should You Replace Your ATAG Boiler Instead?
If you’ve had your ATAG boiler for some period of time then it’s worth considering a new one as you could be saving up to £305* a year in a detached home. Take a look at the table below to see how much you could be saving depending on your current boiler rating and property.
| House Type | G (<70%) | F (70-74%) | E (74-78%) | D (78-82%) |
| Semi-Detached | £200 | £140 | £120 | £120 |
| Detached | £305 | £210 | £180 | £180 |
| Detached Bungalow | £155 | £105 | £90 | £90 |
| Mid terrace house | £175 | £120 | £105 | £105 |
| Mid terrace house | £95 | £65 | £55 | £55 |
Who should I choose to replace my ATAG boiler?
If you think a new boiler is the right way to go then the next big decision is choosing who to replace it. The easy part is knowing that no matter who you get to replace a boiler they must be Gas Safe registered. Now that we’ve got that part out of the way, your choice ultimately comes down to a local engineer or a national company.
Local engineers can offer a very competitive rate and as they tend to be just one man and his van, you’ll get a very personal service from the same person throughout your communications. It’s always a good idea to get a quote from more than 1 engineer to make sure you’re getting the best deal, we recommend getting up to 3.
While branded manufacturers may be slightly more on the expensive side, big brand protection is a huge bonus and they can provide extra service such as ongoing boiler cover.
Boiler Insurance and Ongoing Cover
If your boiler warranty has expired, then boiler insurance is a possible option. You can take out insurance with your energy supplier but you’re absolutely no obligation to do so. When comparing insurance, the best ones will include an annual service and safety inspection, so keep an eye out for them.
ATAG Boiler Warranty
ATAG boilers come with 10 years warranty as standard, giving you peace of mind well after your boiler is installed. One thing you’ll need to know when it comes to any boiler warranty, including ATAG boilers is that the unit must be serviced annually or the warranty will end early.
