A How to Guide on How to Repressurise a MAIN HEATING Boiler

If your MAIN HEATING Boiler displays the error code E119 message, your boiler’s water pressure is low and needs to be repressurised.

While this may seem alarming, do not panic. Repressurising your home’s heating system is a straightforward task that all boilers require from time to time due to general use.

For homes with an annual boiler service scheduled, you might not need to do it as the Gas Safe registered engineer usually tops up the pressure level.

But what steps are involved with repressurising your MAIN HEATING boiler?

Step-By-Step Guide For Repressurising a MAIN HEATING Boiler

All boiler manufacturers, including MAIN HEATING, ensure that repressurising their units is as simple as possible.

The ideal pressure level for a MAIN HEATING boiler is between 1 to 1.5 bars when cool.

If the pressure drops below 0.5 bar, the system will usually shut down and notify you that it needs to be repressurised, the E119 code.

On the other end of the scale, you should bleed your radiators if the pressure level is above two bars.

As mentioned, repressurising a MAIN HEATING boiler is straightforward. Here’s a step-by-step guide to get it done:

Step 1: Turn Off the Boiler

Before working on your boiler (or any), make sure you’ve switched off.

Turning off your MAIN HEATING boiler prevents any risks associated with boiling water.

Allow the boiler to cool for an hour for a more accurate pressure reading.

You can turn off your boiler using the main power switch, or if you’re unsure, you can flip the circuit breaker for your home.

Step 2: Locate the Filling Loop

You’ll need a filling loop to repressurise your boiler’s heating system.

There are two common types of filling loops:

• External filling loop: A detachable, braided silver hose.
• Internal filling loop: Built into the boiler, typically operated with a key or lever.

In most cases, the filling loop system is underneath the boiler. MAIN HEATING boilers are associated with BAXI Heating Systems group, so they may have an EasyFill filling link.

But if this isn’t the case, you will need to attach a filling loop.

Step 3: Attaching the Filling Loop

When attaching the filling loop, ensure the valves are closed.

When shut off, the valve handles should be at a 90-degree angle from the water pipe’s direction.

Remove the plug and cap from the filling loop connection and set them aside for later. Attach the filling loop securely by hand to the domestic hot water inlet. Avoid over-tightening, as this may cause leaks.

Now that your filling loop systems are attached, it is time to open the valves.

Step 4: Open the Filling Loop Valves

Once the loop is attached, align the first valve with the pipe and slowly open the second valve to allow water to enter the boiler’s heating system.

Monitor the pressure gauge, and when it reaches 1 to 1.5 bars, close both valves.

With the EasyFill filling link system, you only need to open and close the valve when the water reaches the desired pressure.

Step 5: Clean Up and Check

If you’ve attached a filling loop to your boiler, you will need to disconnect it. Prepare a bucket and towels to catch any water that spills during this process.

Once completed, your repressurised MAIN HEATING boiler should be ready for use.

However, if you notice that you must repeat this process frequently, whether after a few hours, days, or every week, this could indicate a more serious pressure issue.

What Are the Common Causes of Pressure Loss in a MAIN HEATING Boiler?

Here are the most common causes for a boiler to lose pressure:

Leaks in the System

A small leak in your heating system’s pipes, radiators, or boiler will cause the pressure to drop. Depending on the size of the leak, the pressure may decrease gradually or suddenly.

As you can imagine, finding a leak can be challenging, especially if it’s along hidden pipework inside walls or under flooring.

Faulty Pressure Relief Valve

The pressure relief valve is a critical safety component in any boiler system. It automatically releases excess pressure to prevent dangerous buildup.

However, if the valve is faulty, it may:

• Open inconsistently, causing pressure loss.
• Fail to seal correctly, leading to minor leaks.
• Stop functioning altogether, creating a potentially hazardous situation (although this is rare).

If you strongly think it is a faulty pressure relief valve, call a Gas Safe registered engineer, as they are the only people qualified to do the repair work.

Issues with the Expansion Vessel

The expansion vessel in your boiler helps maintain stable pressure throughout the heating system.

If the expansion vessel becomes damaged or loses functionality, your boiler’s pressure will drop.

This issue requires attention from a qualified Gas Safe registered engineer.

Bad DIY: Bleeding Radiators

Bleeding your heating system’s radiators removes trapped air from the heating system, improving its efficiency.

However, releasing too much water and air during the process can lower the system’s pressure.

If you’ve recently tried to bleed your radiators, this could be the cause.

But if you’re unsure what is causing the loss in pressure, it might be time to get someone to do it for you.

Get WarmZilla To Do It!

Many issues mentioned above, such as faulty components or leaks, will need a Gas Safe registered engineer to fix.

WarmZilla has national coverage and can provide a Gas Safe registered engineer within 48 hours.

If you want to discuss the problem in more detail, please contact one of our professional consultants.