Central heating switching off randomly.

[Des Jennings]

For some weeks now my central heating has been switching off after about ten hours and not refiring. The next morning the heating switches back on a timer and the same issue occurs after a number of hours. Occasionally the blue power light has flashed but on resetting the boiler fires up and the heating stays on. There is no problem with hot water which always fires up and stays on so I suspected, some time ago, the Myson CH valve which I purchased. Yesterday morning the heating did not come on so I decided to change the actuator. After switching the power back on the boiler fired up and I had CH for about 15 minutes before the boiler switched off again. A couple of hours later I switched the CH on again and it stayed on for the remainder of the day and fired up this morning until this afternoon when I noticed the power light flashing. A reset got it going again. I have a two-year-old Bosch boiler and a Sadia cylinder. A limit appears to be reached and then the boiler switches off.

Help appreciated.

 

[ianmcd]

if it is 2 years old it is still under warranty, the blue light flashing is a fault code in the boiler depending on how fast it flashes, your zone valve has nothing to do with it

 

[CBW]

As per @ianmcd, it’ll be under warranty (I missed the bit about 2 years old).

 

[Des Jennings]

if it is 2 years old it is still under warranty, the blue light flashing is a fault code in the boiler depending on how fast it flashes, your zone valve has nothing to do with it

Thanks for that. There appear to be two main issues. The first one is the boiler switching off without the blue light flashing and refusing to switch on again for some hours. The second issue is the occasional switching off randomly and the blue light flashing which is resolved by a reset. This particular boiler does not give a code indication but I will monitor the speed of flashing.

 

[ianmcd]

The speed of the flashing is the code indication

 

[Des Jennings]

As per @ianmcd, it’ll be under warranty (I missed the bit about 2 years old).

The Covid-19 situation has meant that I have been reluctant to have people working inside the house for any period of time, so it is fortunate that the heat has been on most of the time. The situation is changing now that replacing the valve actuator may not have resolved the issue.

 

[ianmcd]

post a video of the blue light flashing when it does it, I am guessing restricted condensate trap but need to see it doing it

 

[Des Jennings]

post a video of the blue light flashing when it does it, I am guessing restricted condensate trap but need to see it doing it

Thanks. I will video the blue light. I have to say that the condensate trap is not situated very well and linked to the waste pipe under a sink unit. I did wonder after the trap was fitted a couple of years ago whether the angle of the waste pipe, very little angle, could have any effect on the running of the boiler. Although there was no issue for some time.

 

[ianmcd]

If you can remove the connection under the sink see if it is gunged up with soap or stuff

 

[Des Jennings]

post a video of the blue light flashing when it does it, I am guessing restricted condensate trap but need to see it doing it

Here is a video of the blue light. The green light had been flashing on then off occasionally.

If you can remove the connection under the sink see if it is gunged up with soap or stuff

I am hoping to post a video soon. Is the boiler programmed to detect an issue with the condensate?

 

[ianmcd]

I am hoping to post a video soon. Is the boiler programmed to detect an issue with the condensate?

yes it will detect a build up

 

[Des Jennings]

Here is a video of the blue light. The green light had been flashing on then off occasionally.

I am hoping to post a video soon. Is the boiler programmed to detect an issue with the condensate?

 

[ianmcd]

Yes flashing code and what you describe does sound like a partiallly blocked condensate

 

[Des Jennings]

Yes flashing code and what you describe does sound like a partiallly blocked condensate

Thanks. I've attached images of the condensate set up which doesn't look ideal to me.

 

[CBW]

The condensate trap is under the boiler, this is the waste where it connects, which could also be blocked.