What should my boiler pressure be?

What should my boiler pressure be?

Your boiler pressure should be between 1, to 1.5 bar. The majority of boiler manufacturers recommend a working pressure of 1.3 bar to be the ideal boiler pressure.

As a gas engineer, this is a question that I hear often and we get calls from concerned homeowners that fear their boiler pressure may be dangerously high.

There are a few factors that will affect your boiler pressure so in this guide we will cover the main issues and give you tips on what to look out for to keep your boiler at its optimal pressure all year round. All boiler models should run at about the same boiler pressure so you are redt assured that it is safe to follow this guide regardless of the boiler brand that you have in your home.

What pressure should my boiler be in the summer?

When the weather is warmer you will use your boiler lees, this inactivity can cause the boiler pressure reader to drop. Some combi boilers may give inaccurate readings during this time, this is especially true with combi boilers and it is not uncommon to see readings between 0.9-1.1 during these periods.

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What should my boiler pressure be when in use?

When your boiler is hot and in use you may see a prise in boiler pressure of between 0.3 – 0.5 bar, adding this to the recommended standing pressure can increase the boiler pressure to the recommended boiler pressure should be between  1.5 – 1.8 bar.

This is the maximum pressure that you see, if you start to see higher numbers than 1.8 then you may have an issue.

What should my boiler pressure be in the winter?

When we are using our boiler to the max capacity, in the winter months for example when heating the home you can expect an increase in boiler pressure.

When the heating is on there will be water expansion as water is getting heated up in pipes and radiators, this will cause an increase in the boiler pressure. If the pressure increases above 1 bar from its starting pressure it can be an indication that there is an issue with the pressure release valve or expansion vessel.

Is the pressure of my boiler too low?

You may have an issue with your boiler pressure being too low. On a common Vaillant combi for example, if the pressure drops below 0.8 bar you will get a flashing light appear as a warning.

The boiler may lock and you will need to reset it. This is a simple job and can be fixed by adding some water into the external filling loop and this will in turn increase the boiler pressure.

 Boiler pressure keeps dropping

If the pressure of your boiler keeps dropping even after resetting then there may be a real issue that needs dealing with. It is likely that there is a leak somewhere and we would recommend that you give us or another gas safe team a call to come and inspect your boiler.

What can I do if my boiler pressure is too high?

If your boiler pressure is too high, there are a couple of things that you can do to try and relieve that pressure before giving a gas engineer a call.

One of the most common causes we see is that the boiler pressure has just been topped up and the customer was a bit heavy-handed when doing it. If that is the case you can blled water from a towel rail, this will relieve the pressure and fix the problem.

To do this you will require a bleed key and something to catch the water in.

Use the key to loosen the valve until water starts to seep out, do this slowly and then close the valve. Check the pressure again, you can repeat this process until the pressure has come down to the optimal pressure ideally 1.3 bar. 

You may go too far in the other direction and cause low pressure. If this happens, as with the previous tip earlier in the guide, you can simply add water via the filling loop to increase the boiler pressure.

If you have any questions regarding your boiler pressure please contact our Gas safe team today

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