Boiler Repair

A boiler repair is normally a fixed cost should a breakdown occur. An annual boiler service by Bristol Boiler Installers will pick out any potential faults and prevent most boiler breakdowns.

However, a service will not be a fool proof way of ensuring your boilers peak performance and a breakdown may occur.

A combi boiler is responsible for supplying your home with both heating and hot water. The downside of this is if the boiler completely shuts down, there is no back up.

There can be many reasons why a boiler may breakdown or underperform but there are some common problems that us gas engineers will see on a daily basis.

Boiler repair Bristol

A boiler repair call out within Bristol is set at a low cost of £90.00. This includes the call out, first hour charge and the repair itself (providing the repair is completed within the hour and no parts required).

If we are required to source parts then a quote will be given with no obligation to proceed.

If for whatever reason we are unable to diagnose the fault, no charge will be applicable.

So why would a combi boiler completely shut down?

Here are a few common reasons why:

  • Low water pressure
  • Pump failure
  • Fan failure
  • Sensor failure
  • Diverter valve failure
  • Scale build up*


The joys of living in Bristol

In areas such as Bristol, hard water (scale) plays its role extremely well in causing a boiler breakdown. Just have a peak in your kettle, do you see any lime scale? If yes, then without adequate protection it will also be in your boiler.

All of the above faults will either cause the boiler to completely shut down or seriously under perform at best.

First thing to check is your boiler pressure

Topping up your boiler is usually a simple process. Below you’ll find some information on how to top up your boiler should it need it.

Here are some examples of a Vaillant and Worcester-Bosch filling loop:

repair2 repair1

The Vaillant and Worcester-Bosch filling loop may vary depending on the model but the above 2 are the most common.

How to fill your heating system using the above Vaillant or Worcester-Bosch filling loop.


  • Locate the 2 grey handles as seen above
  • Locate the pressure gauge*
  • Turn the right hand handle 90 degrees
  • Now turn the left hand handle slowly while observing the pressure gauge
  • You want the pressure gauge pin to be somewhere on the grey
  • Once you have achieved this, close both grey handles. Job done.

  • Locate the white plastic key*
  • Fully insert the key into the slot (shown above)
  • Twist the key to the right to ensure its locked in position
  • Locate the white plastic piece to the right of the key
  • Turn this anti clockwise to begin filling your boiler
  • Locate and observe the pressure gauge
  • Stop filling (turn the white plastic piece clockwise) when the gage reads 1bar
  • Turn the key to the left to unlock and pull down (may be stiff)

If you look closely at the 2 grey handles when in the off position (as above), you will the word ‘CLOSED’. Fool proof I would say.

*The pressure gauge may not be external on some newer Vaillant models.
If this is the case, you can check the pressure by pulling down the boiler case flat and pressing the central heating symbol twice. You will now see the boilers pressure in bars on the LCD screen.

The pressure you are looking for is around 1.1 bar when cold.

It’s not uncommon for the filling key to take an extended vacation when required. The key is essential to filling your boiler so if it has gone missing you will have to purchase a new one (widely available).

*Before jumping the gun and assuming the filling key is missing, check (if you have this) the plastic casing which slots underneath the boiler to hide the valves, there is a slot there to hold the key.

repair-loopHere are some examples of an external filling loop:

This type of filling loop is simple to use, simply turn the black handle/s 90 degrees and observe the pressure gauge. When the pressure gauge reaches around 1.1 bar, turn the handles off.

If you successfully manage to fill your boiler and heating system up you shouldn’t have to do so again for a few months. Should you find you have to repeat this process on a regular basis then it’s likely that you have a leak or a fault within your boiler.

Unsure on how to re pressurize your boiler? Or require a boiler repair please do contact us on 07771546105 or fill out the contact form on our contact page and we will get back to you.

Have you had enough of your boiler? Thinking about a new one? Click on the link to get a boiler replacement quote online within 30 seconds: