How to Reset Your Vaillant Boiler Safely

There’s never a good time for the heating to go off, especially on a cold morning when everyone needs a hot shower. If you’ve got a Vaillant boiler and it has stopped working, the good news is that a simple reset is often all it takes to get things going again.

We’ve put this guide together to walk you through how to reset your Vaillant boiler step by step, what to check first and, just as importantly, when a reset isn’t the answer and it’s time to call in a Gas Safe engineer.

Why Would You Need to Reset Your Vaillant Boiler?

Vaillant boilers are designed to protect themselves. If something isn’t quite right, such as the flame not lighting or the water pressure dropping too low, the boiler will lock out and stop working until the problem is cleared.

When this happens you’ll usually see a fault code on the display starting with an F, such as F.28 or F.29. A reset tells the boiler to clear the lockout and try again. If the cause was a one-off blip, like a brief interruption to the gas supply, the boiler should fire back up as normal.

Quick Checks Before You Reset

Before you reset your Vaillant boiler, it’s worth spending a couple of minutes ruling out the simple things. You’d be surprised how often one of these is the real cause:

• Power: Make sure the boiler has power and the switch or fused spur next to it is on.
• Gas supply: Check your other gas appliances, such as the hob, are working. If you’re on a prepayment meter, make sure there’s credit on it.
• Water pressure: Look at the pressure gauge on the front of the boiler. It should normally sit between 1 and 1.5 bar when the heating is off.
• Thermostat and timer: Make sure the thermostat is turned up and the timer or smart controls are calling for heat.
• Condensate pipe: In freezing weather, the small plastic pipe that runs from your boiler to a drain outside can freeze and block.

If the pressure is low, you’ll need to top it up before a reset will do any good. Our guide on how to re-pressurise your boiler explains how to do this safely.

Step 1: Find the Reset Button

Before you can reset your Vaillant boiler, you’ll need to find the right button. On most Vaillant models, including the popular ecoTEC plus and ecoTEC pro, you’ll find the reset button on the front control panel. It’s usually marked with the word “reset” or a circular arrow symbol.

On some older ecoTEC models the controls sit behind a small flap at the bottom of the boiler, so gently pull this down if you can’t see any buttons straight away. Newer models with a digital display may have the reset option within the menu, and your user manual will show you exactly where to find it.

Step 2: Press and Hold the Button

To reset your Vaillant boiler, press the reset button and hold it for around three to five seconds, then let go.

The display may go blank briefly or show the boiler restarting. Don’t keep pressing the button repeatedly during this time, as you need to give the boiler a chance to go through its start-up checks.

Step 3: Give It a Few Minutes

Once you’ve pressed reset, wait a few minutes. The boiler will run through its safety checks and then try to light.

You should hear the fan start and the burner ignite. It’s normal for this to take a little while after you reset your Vaillant boiler, so try not to worry if nothing happens straight away. Turn on a hot tap or turn up the thermostat to check that the boiler is producing heat and hot water as normal. If the fault code has disappeared and everything is warming up, you’re all set.

Step 4: If It Doesn’t Work, Try Once More

If the boiler locks out again, it’s fine to reset your Vaillant boiler one more time. Sometimes it takes a couple of attempts, particularly if air has got into the gas line.

However, we’d always recommend that you don’t reset it more than two or three times. If the fault keeps coming back, the boiler is telling you there’s an underlying problem that a reset can’t fix, and pressing the button over and over won’t change that.

Common Fault Codes You Might See

Knowing what the code means can help you decide whether it’s worth trying to reset your Vaillant boiler or whether it needs a professional. Here are a few of the most common ones:

• F.22: Low water pressure. Top up the pressure first, as a reset alone won’t solve this.
• F.28: The boiler has failed to light. This is often linked to the gas supply or a frozen condensate pipe.
• F.29: The flame has gone out while the boiler was running, again often down to the gas supply.
• F.75: A problem with the pump or pressure sensor, which will need an engineer.

You can find a fuller list in our Vaillant boiler error codes guide.

What to Do About a Frozen Condensate Pipe

During a cold snap, a frozen condensate pipe is one of the most common reasons a Vaillant boiler stops working. You might also hear a gurgling noise coming from the boiler.

To thaw it, pour warm water (not boiling) along the outside section of the pipe, or hold a hot water bottle against it. Once the ice has cleared, you can reset your Vaillant boiler and it should start up again. Only do this where the pipe is easy and safe to reach at ground level.

When to Call a Gas Safe Engineer

A reset is a safe, simple thing for any homeowner to try, but there are times when you should stop and get help. Please call an engineer if:

• The same fault code keeps returning after two or three resets
• You can smell gas (leave the property and call the National Gas Emergency number on 0800 111 999 straight away)
• There is water leaking from the boiler
• The boiler is making loud banging or unusual noises
• The pressure keeps dropping after you’ve topped it up

Never take the casing off your boiler or try to repair anything inside it yourself. Any work on a gas appliance must be carried out by a Gas Safe Registered engineer. Our team carries out boiler repairs across Teesside, County Durham and North Yorkshire, so if you’re stuck, just get in touch with us here.

Frequently Asked Questions

Is It Safe to Reset My Boiler Myself?

Yes. Pressing the reset button is designed to be done by the homeowner and is completely safe. What you shouldn’t do is open the boiler up or attempt any repairs inside it.

How Many Times Can I Reset My Vaillant Boiler?

We’d suggest you only reset your Vaillant boiler two or three times at most. If the boiler keeps locking out, there’s an underlying fault that needs looking at by an engineer.

Why Does My Boiler Keep Needing a Reset?

Regular lockouts are usually a sign of a problem such as a faulty part, a blocked condensate pipe or a pressure issue. An annual boiler service helps catch these problems early, before they leave you without heating.

Will Resetting My Boiler Change My Settings?

No. A reset simply clears the lockout. When you reset your Vaillant boiler, your temperature settings, timer and heating schedule should all stay the same.

Keeping Your Vaillant Boiler Running Smoothly

Knowing how to reset your Vaillant boiler can save you a lot of stress, and in many cases it’s all you’ll need to get the heating back on. Just remember to check the simple things first, give the boiler time to restart and don’t keep pressing the button if the fault won’t clear.

If you’re ever unsure, or the problem keeps coming back, our friendly team is always happy to help. A quick call can put your mind at ease and get your home warm and comfortable again.