Bosch Boiler Tutorial

If you are a resident of the United Kingdom, then a quick peek out of the window will probably confirm the obvious – winter is here for the coming months. This means more layers of clothing, horrible freezing cold mornings chittering in the car and higher energy prices as the heating will be on more often than not. Therefore, you’ll be looking to try and made amends elsewhere in your budget to avoid spending more than you need to – but the problem is that when your boiler goes into being used more often than not, it can cause issues.

These issues can be pretty frustrating and leave you with an irritating and painstaking chase to try and cover the costs. Efficiency will drop, your boiler will stop operating as well as it should and you’ll be using more energy just to get the same efficiency you should have been in the first place. In the winter when your bills are going up as it is, it’s nice to be able to get these problems fixed. The issues is that most boilers read like a section of an ancient mystery puzzle and only provide you with an error sign – and a very vague one at that – to tell you what the problem is.

Without an eidetic memory you might struggle to remember all of these facts and figures, and the meaning behind each problem. This means that no matter what the problem is you are stuck with needing to call somebody out to sort it. While we are more than happy to come out and have a look, we are talking about saving you money here not costing you extra! Instead, we’ve created a master list for you to use for the BOILER range of boilers, so that you can find out what the problem is yourself.

Finding a solution becomes easier then but it also means that if you do need professional assistance you can give them an instant problem to correlate with their own master list, we fix any problem with these boilers so if the solution to fix the problem is out of your hands you might want to give us a call – we are more than happy to help out if you need us. Either way, you’ll now be able to know what your boiler is actually suffering from and then it becomes easier to find a solid solution.

The Faults

No blue light, and no lockout reset button being used – Typically, this is a problem with the power itself at the control board. This could be the mains supply that is damaged; it could be the mains switch on the boiler also.

Additionally, you want to be looking at Fuse F1 or Fuse F3, as well as the transformer. Usually, though, the most common solution is just to replace the control board – it depends on how severe the damage actually is. When you get no response as provided above, it’s best to give us a call as the fault could be more serious.

Blue light on but no lockout reset button being used – This can be one of several different problems. The most common issue is that the boiler is not operating during the demands of the central heating system, or that it’s not able to work with your external roomstat timer.

Additionally, it could be the boiler not operating during the demand from the hot water or even during any typical demand – this is a big problem. When there is no operation from your central heating, you’ll want to have a look at your timers, your diverter valve and the control board.

If the boiler isn’t operating with your thermostats instruction, then you might find that the thermostat is damaged or that it is not giving enough power back. Otherwise, you want to be looking at either the fan of the control board for the problem. Again, this can be serious enough that it might require our assistance.

Slowly flashing blue light, and a flashing lockout reset button – This usually means that there is a lockout with the ignition. Make sure that there is gas present and that your boiler is at the right pressure levels. Next, you want to check the Combustion CO2 level. Check the ignition connections and harness as well, as there could be damage here.

Alternatively, give the gas valve a check and ensure that there is a low voltage harness connection, and that the coils are between 140-190 Ω. If none of these solutions appear to give you any relief then replace the control board by giving us a call.

Slowly flashing blue light, and a flashing lockout reset button – The same as above, except this time the light will be flashing from mostly on to off, rather than the other way around. This usually means there is overheating in the flue or that the heat exchanger is overheating. The flue is caused by blockage or damage to the heat exchanger, so give this a check regardless.

To sort the heat exchanger check that all air is vented, the water pressure is right and that all connections are fitted properly. Also check for any leakages or blockages within the water – also check the connections between your thermostats and your systems.

Quickly flashing blue light, no flashing lockout reset button – This is usually a volatile lockout, which can be a bit of an issue. Make sure that your temperature sensor is sitting at anything from 8,000-20,000 Ω and that the connection between the low voltage wiring harness and the connections to the sensor are dealt with properly. Check out the fan harness connections, as well, and that the code plug has been properly fitted to the system in the first place.

Quickly flashing blue light, flashing lockout reset button – This is an internal fault with the actual boiler and requires a replacement of the control board – again, give us a call if this is the problem and we can diagnose further.

2-5 pulses – This is not a fault code and means that your service mode has been selected at the minimum (2) or maximum (5). Simply press the ‘service’ button on your boiler to reset the boiler back to normal.

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