🕑 6 minutes read
Is your Worcester Bosch boiler showing the A1 code? There’s no need to panic if it does. This blog will explain how you can return your property to that warm cosy feel once again. A flashing fault code is always a sign that something has malfunctioned. We'll highlight some of the possible causes and what needs to be done to get the system back online and running smoothly once more. It might even be something simple you can fix yourself.

Worcester Bosch Boilers

Worcester Bosch brings together the engineering expertise of German technology. Their Greenstar range of boilers is highly respected in the heating industry, receiving CORGI's Boiler of The Year Award and Which?' Best Buy for the last decade. Committed to energy efficiency, you can trust a Worcester Bosch boiler to cater for your home heating and hot water needs now and into the future.

Worcester Bosch boiler A1 fault

A1 fault code can be caused by a jammed, dry or air-filled pump. This pump is responsible for pushing warm water to every radiator and hot water outlet (taps, showers etc.). If you are experiencing problems with either, i.e., tepid water from the hot taps and variations in radiator temperatures, it may be flagged by the A1 error code. Your user handbook should provide more details on how to solve this problem based on the model of the boiler.

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Worcester Bosch boiler A1 Fault
Causes and fixes

➜ Error 1: Pump is idle.
Over time, pump bearings and the spindle that rotates can wear over time. Wear on the bearings and spindle can eventually cause them to seize up or become jammed in position.

The noise indicates that the pump or bearings are on the way out. The pump may sound strained or emit a slight grinding noise, coupled with the pump casing becoming warmer, even hot (hot water circulating will naturally raise the temperature of the pump casing). Noticeable vibrations throughout the system can indicate a pump problem. This typical sign of wear and tear in aged boilers could be down to the shaft, the bearings, or both failing. If the pump is positioned at an awkward angle, this could contribute to wear and tear problems. pumps ideally need to be placed horizontally to work efficiently.

Sometimes, repairing the pump's worn-out bearings or replacing them is much more economical than changing the boiler. Some parts are inexpensive, but the labour time will be the main expense as accessing an internal pump inside the white box and replacing it can be time-consuming.

Prices can vary depending on the make and model of the boiler, but typically the cost is somewhere in the region of £150+. The engineer will be able to determine immediately if the pump has been put correctly positioned or not. If the pump has significant damage, then the only option is to replace it.

➜ Error 2: Internal heating system air.
If air gets trapped in the pump, it can prevent circulation, similar to a blockage. Commonly known as an ‘air lock’. A pressure drop may occur if a large amount of air is in the system or the pump itself, and it won't operate effectively if it drops below 1.2 bars. Check the gauge on the front of the boiler for confirmation.

Most boilers will gradually drop pressure, but if there is a sudden significant drop, a deeper problem may need fixing. Air that causes these pressure drops can enter the system through a leaky component or pipe, but it can also build up from the water flow into the home, and with certain repairs, the system will need to be re-pressurised.

Regular radiator bleeding can remove any excess air from the system before it accumulates, causing a bigger problem, like air locking the pump. If heat is unevenly distributed in a radiator, i.e., cold on top and hot on the bottom, it indicates a radiator needs bleeding. Sometimes banging the pipes can indicate trapped air in the system.

➜ Error 3: Excessive sludge in the system can block the pump.
As water flows through pipes, microscopic debris and rust break down inside the radiators, forming a gloopy sludge. This can lead to poor circulation of water and any debris/sludge circulating the system and is not good for the pump or parts of the boiler. Older heating systems or those without a system filter are more susceptible to this common problem.

Engineers can quickly identify blockages, such as sludge buildup in the system (radiators) or pump. Removing and cleaning the magnetic system filter is often necessary to get your system running efficiently - provided bearings and shafts aren't damaged! Request a system filter clean-down (if you have one fitted) during your next annual boiler service.

If the system is sludge rich, the engineer may recommend a process called a 'power flush' or ‘chemical flush’. A Power Flush involves pumping the sludge out (under pressure) from the system and radiators. Prices vary depending on the number of radiators in a property, but overall costs will include labour + materials. You may want to consider investing in a magnetic system filter for your central heating system to capture all those nasty particles suspended in the water circulating the system, which get into the pump and boiler parts. A magnetic system filter can cost £120 + VAT and installation costs in the region.

Home heating issues can be a major inconvenience, but serviceteam is on hand to ensure your central heating is in tip-top condition. Serviceteam is Worcester Bosch accredited boiler installer, so rest assured your repairs and installation will be in safe hands.

Have issues with your central heating system? Then call serviceteam and book an appointment with our heating and plumbing team

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