Vokera linea 28 hot water issues

[taylorb13]

I have just had a problem with my HW heat exchanger, when the temp got to 43 Degrees it cut out and reset the flame. I replaced the HE and that solved the problem.

Now I have new problems with my hot water. When the boiler is cold I get hot water no problem, but if I try the hot water tap when the boiler is still warm, the flame lights for around 5 seconds the cuts out and keeps lighting for another 5 secs and this continues..

Please can someone help me??? Is it the thermistors???

 

[weareleeds]

Probably thermister, when you changed plate heat ex was there any black deposits on the 2 c/htg connections?

 

[gas4you]

Are we correct in assuming it was the plate HE you changed?

 

[bengasman]

Sounds like typical case of fighting the symptom, leaving the problem. If the h/e gives up due to clogging up, you should get the carp out of the system rather than replacing the part. The typical thing to happen would be running bath or shower and temperature fluctuating because the boiler cycles.

 

[Agile]

Might be a fan/vent/APS problem!

All CORGI jobs.

Tony

 

[taylorb13]

Hi, Thanks for all your responses..
Now I get the same problem on the CH aswell as the HW. keeps re-starting the flame after 5 seconds.

Yes the water in the system was pretty dirty, I have installed a mag-netech device and put some solution in the system to de-scale /sludge it.

When I changed the HE the 2 connections at the bottom had black deposits.

It was the secondary (HW) heat exchanger I replaced not the primary. I have taken the primary one out and de-scaled it.. After doing the de-scaling it worked ok for a few hours then went back to cutting out.

 

[gas4you]

See Agiles post above.