A How to Guide on How to Repressurise an Alpha Boiler

Nothing is worse than discovering by surprise that your Alpha boiler isn’t working due to low pressure.

The error codes 0E37, E10, or the flashing red and yellow lights alternating between each other indicate that you must repressurise an Alpha boiler. Many homeowners might be surprised to learn that repressurising their boiler is a simple enough DIY task most could do.

Also, it might come as a surprise, but most modern boilers must be repressurised once or twice a year. It might be less if you have

However, when you are served with the two error codes above, you will want to ensure your system is circulating correctly without blockages. If you have an annual service booked with a Gas Safe registered engineer, it might not need topping up.

When seeing error codes 0E37 and E10, you should ensure that the system’s circulation is free-flowing and without any blockages.

However, if your Alpha boiler needs topping up more frequently and is acting strangely, you could be required to call in a Gas Safe registered engineer to check it.

A boiler can lose pressure due to multiple reasons.

Reasons Why Your Boiler Is Losing Pressure

All boilers (no matter the brand) will lose pressure over time from general use. However, there are many reasons why it would lose pressure.

When your Alpha boiler displays error codes for low pressure, it should automatically switch itself off to prevent damaging itself.

But if you are getting this error code multiple times a year, it could be the result of several common boiler issues. These common issues include the following:

A Leak In The System

For your boiler to work efficiently, it must be able to maintain its system’s pressure. Even a tiny leak in your heating system’s pipes, radiators, and inside the boiler itself can cause the pressure to drop.

Locating (a) leak/s can be difficult, as they’re not always visible. Leaks can be located along a hidden pipeline length in a wall or under the flooring.

Other telltale signs that your boiler’s heating system leaks include:

• Visible water or damp spots
• Inconsistent heating or hot water
• Strange noises (gurgling or hissing)
• Unexplained increase in water usage
• And unusual smells (dampness or wet metal smell)

However, if you have to top up the water levels regularly, you will need to contact a Gas Safe registered engineer to find and fix the leak.

Broken Pressure Relief Valve

One of your home’s boiler’s most crucial safety devices is its pressure relief valve. Its primary function is to release pressure if there is too much of it.

When the pressure builds up to a critical level, the safety device automatically opens and releases steam. But if it is not working correctly, it could leak water or realise steam too soon.

In the worst-case scenario (and very unlikely), the valve could fail to release built-up pressure, posing a significant risk.

The Expansion Vessel Isn’t Working

Your boiler’s expansion vessel plays a significant role in managing your system’s water, absorbing the increased water pressure created by the central heating system.

Your boiler’s expansion vessel contains a flexible diaphragm and air cushion, which work together to regulate the heating system’s pressure and help prevent sudden spikes that can damage it.

If this expansion vessel malfunctions, becomes damaged or loses its air charge, it cannot maintain the pressure balance in your system. A broken expansion vessel will result in a pressure drop.

To repair your system’s expansion vessel, you will need to contact a Gas Safe registered engineer.

Chilly Weather

When temperatures drop below freezing for an extended period, your boiler’s external condensate pipes can freeze.

To diagnose that your Alpha boiler has a frozen condensate pipe, you will need to look for the following:

• An odd gurgling noise
• Dripping water under the boiler
• Boiler switches off
• And no hot water or heating

Some Alpha boilers might show an error code of E01, but most don’t have this functionality.

Bleeding Radiators

Bleeding your home’s radiator is a simple task that most homeowners can tackle themselves. The purpose of bleeding your radiators is to release trapped air from the heating system.

But everyone makes mistakes occasionally when dealing with a simple task. If an eager DIYer releases too much water after the air bubble, the system’s pressure can drop.

Best Pressure Level For Your Alpha Boiler

Maintaining the correct pressure is essential for boilers to perform as efficiently as possible.

For most boilers in the UK, the ideal pressure range is between 1 and 1.5 bars. However, always consult your boiler’s manual for specific recommendations, as some models may have different requirements.

But generally, your boiler’s pressure gauge will indicate the best pressure level with green sections.

Step-By-Step To Repressurising Your Alpha Boiler

It’s essential to follow these instructions closely when repressurising your Alpha Boiler. The first step is arguably the most important: ensuring it is safe to work on.

Step 1: Turn Off The Power

Usually, you can turn off your boiler’s power supply by the closely located fuse spur (or, for the layman, a big switch). If you can’t find this switch, sometimes boilers are wired into regular home sockets.

But if you are uncertain that you’ve turned off the boiler, turn off all the power in your home from the switchboard.

Alpha’s website suggests that you let the system cool down for 4 to 6 hours before starting the repressurising process.

Step 2: Identify And Find The Filling Loop System

A boiler’s filling loop system connects your unit to the home’s cold water mains. Your filling loop system is used to top up the water levels in your boiler’s heating system.

A filling loop is usually located underneath your boiler. There are also two types of filling loops: external and internal.

While these systems are different, they do the same thing.

External Filling Loop

An external filling loop is a metal braided hose that connects your main cold water supply to the central heating system. These loops are usually stored near the boiler. Also, an external filling loop has two valves:

• One controls water flow from the mains.
• The other prevents backflow from the heating system into the mains.

You might need a flat-head screwdriver to open and close these valves.

Once you’ve repressurised your boiler, remove the external filling loop. Leaving it attached increases the risk of contamination.

Internal Filling Loop

An internal filling loop is integrated into the boiler and is common in modern systems. It is more convenient because it remains permanently installed and is easier to operate. Depending on the design, you might need a key to operate the loop or use a lever tap.

Some systems use a component called a rigid filling link, which is also typically stored near the boiler. This link is a bent copper pipe with two brass wing nuts and washers.

When attaching a rigid filling link, make sure both the water mains and boiler taps are off. The lever should be positioned perpendicular to the pipe.

Remove the system’s blanking caps (which protect the threads and outlets from debris).

Position the washers inside the wing nuts and gently tighten the rigid filling link into place. Avoid over-tightening, as this can damage the threads and cause leaks.

Once the filling loop is securely in place, you can move on to the next step in repressurising.

Step 3: Opening The Valves

As we mentioned, both filling loop systems have two valves to ensure that the water from the mains flows in one direction.

Open the first valve, allowing cold water from the mains to fill the loop. When ready, gently open the second valve to the boiler’s heating system. Don’t open the valve all the way, as this will fill up the system too quickly, overpressurising it.

Allow the water to flow into the system slowly. At the same time, you must monitor the boiler’s pressure gauge.

You should see the needle start to rise. Wait for the needle to move to the green area on the gauge, and close off the second when happy with the pressure level.

Step 4: Closing The Valves

Once the Alpha boiler’s pressure gauge reads one bar, it is time to close the valves. Try not to let the pressure creep over one bar, as when you close the valves, the reading on the gauge will rise a little.

Closing the valves will happen in the opposite sequence you turned them on in.

This means first turning off the valve feeding into the boiler’s heating system and then the valve allowing in the cold water from the mains.

When removing an external loop, have a towel or bowl nearby to catch the water in the pipe.

Step 5: Turn It Back On

Always wait a few minutes for the pressure gauge to settle before turning it back on. But once the reading is firmly set at a safe level of 1 to 1.5 bars, it is time to turn your Alpha boiler back on.

After turning the boiler on, monitor the pressure level to ensure it stays within the acceptable range. If it starts to rise above the acceptable pressure level, you need to drain some excess water out of the system.

Step 6: Lowering The Water Pressure

You will want to bleed your radiators to lower the pressure in your boiler system. The first step in bleeding your radiator is to find its key or whether you can use a flat-head screwdriver.

When bleeding your radiator to adjust its pressure level, you will need an additional person to monitor the boiler’s pressure gauge to tell you it is at the desired level.

We’ve covered the steps required to bleed a radiator, and it is another simple task most homeowners can do themselves.

However, if you’re struggling to repressurise your Alpha boiler, it might be time to call a professional for help.

Call WarmZilla To Help You

While it is noble to learn a new skill, sometimes it’s best to seek help from a professional.

WarmZilla offers emergency boiler repair services within 48 hours anywhere in the UK.

Feel free to talk to one of our many experts. They can advise you on the next best step.