Boiler sounds and intermittent H/W

[hatstand69]

Hi,

I have a Baxi 105E, that sounds like it’s running for a few seconds even with no C/H or H/W demand. It does it every 15 minutes or so. It also gives intermittent H/W. It will run for a few minutes, then a minute of cold then back to H/W.

Does anyone have any ideas?

 

[ChrisR]

1) Faulty flow switch, and
2) sludge

 

[hatstand69]

Thanks ChrisR. I'll get the manual out and order a flow switch.

Are there any recommended products that are best for cleaning the sludge out of the system? Then inhibitors to stop it happening again.

 

[ismellgas]

theres a few things you can do to clean the system, get a power flush or use inhibitors or install a filter such as this.. http://www.plumbnation.co.uk/site/fernox-total-filter-tf1-magnetic-filter/

 

[hatstand69]

After reading around a bit. I was planning to drain the system, add fernox cleaner. Run the system for the time it says. Drain and run it a few times to clean out all cleaner. Then add an inhibitor. As well as sorting the flow switch.

Am I on the right track?

 

[Agile]

I presume its not an "instant" ?

They have to run every 15-20 minutes to heat up the internal store.

The alternating hot water may be a blocked/scaled secondary heat exchanger.

Tony

 

[hatstand69]

Hi,

It's a Baxi 105HE It gives hot water straight away. Would the cleaner clean out the heat exchanger or would it need replacing?

 

[Agile]

Does it have the word "instant" anywhere?

They might have given up the instant version when they brought out the HE model. But if it does have DHW preheat that would explain the firing up every 15-20 minutes.

Cleaning a plate HE usually means removing them and using an acidid cleaner. Or just replacing them.

Cleaning in situ is not very effective if they are significantly blocked.

Tony

 

[hatstand69]

Sorry for the late reply, I had to work away from home and thank you for all the help. I have add sentenel x400 to clean the C/H.

When the C/H is demanded the plunger comes out and the C/H works fine. But when H/W is demanded without the C/H running both the H/W and C/H plungers come out. Is that the way it's supposed to work?

 

[hatstand69]

I think, it's about time I gave up on this problem and called in a bolier specialist. Can anyone recommend one in the Newcastle area?