glowworm flexicom cx30

[jwinnette123]

boiler jkeeps cutting out F25 keeps comming up on display...
new pressure relief valve... new pump... system cleaned out...
been told an air lock... bled radiators for last 4 days....
any suggestions....

 

[naanbread]

F25 is a temperature differential fault. It's telling you that the flow and return difference is excessive. If you gain access into the diagnostic menu (instructions tell you how) and look at D40 and D41. You will see that the difference between the two is 30 degrees or more. Lack of circulation causes this so check the flow filter - located in the left hand hydro block on the flow and make sure the rubber flow link tube isn't blocked. It will most likely need these cleaning out and make sure the system is as clean as you can get it.

I hope this helps

NB

 

[ollski]

Change the awful flow and return thermisters if the basics fail, usually does the trick.

 

[naanbread]

Change the awful flow and return thermisters if the basics fail, usually does the trick.

Don't change the flow and return thermistors! The fact it is showing this fault almost proves they are reading correctly. They are there to sense temperature based on an NTC thermistor reading. They must be reading something to see a high difference and show this fault therefor they will be fine!
I can't imagine this "fault finding" ever fixing this fault.

If you want to test the thermistors to prove they are ok it's simply a resistance check at room temperature.

But as I stated above, it's very unlikely to be a component failure within the boiler and most likely something that's blocked through poor quality of water. Check the filter mentioned and feel the rubber part of the flow pipe, does it feel hard and crunchy? If yes; you have dirt in the system causing the issue.

 

[ollski]

I can happily show you dozens it has fixed for me after circulation problems have been investigated. If one of the sensors intermittently gives a false reading it goes straight into the fault code. Not trying to say your advice is wrong but if the fault code is randomly appearing just change them.

 

[Piers1989]

I can happily show you dozens it has fixed for me after circulation problems have been investigated. If one of the sensors intermittently gives a false reading it goes straight into the fault code. Not trying to say your advice is wrong but if the fault code is randomly appearing just change them.

yeah i know what you're saying, but they only change based on a temperature related resistance. I have never had this fault where its down to thermistors.

Yes they are a cheap part to change, but im a strong believer of changing whats faulty rather than what might be causing it.