Vokera Plate Heat Exchanger Problems

[srj321]

Hi,

I appear to have a problem common with the Vokera Linea 24 combi boiler from reading some of the posts on this forum, plus another problem as well.

Quick summary of the situation is that the gas heating the hot water would cut out when it reached approx 50C and then would fire up again once the water was running cold and heat up again to 50C and so on. Had plumber round who said heat exchanger was probably blocked, so he cleaned that and also said a powerflush, along with magnetic filter would help stop the problem happening in the future. This seemed to cure the problem for approx 2 days, but then the pressure started to rise on the boiler and the heating cycle on the hot water has also returned. I have drained the system down a bit to reduce the pressure but it keeps rising back up again - it is not a fault with the filler loop as that is not connected.

Is it possible that both problems are related to the heat exchanger again. If so is it an easy thing (and cheap) to replace this.

Many thanks for any input.


srj321

 

[petit_pablo]

Its possible the two issues are related and the sludge has eaten through the inside of theplate eat exchanger. This would cause the cycling and pressure rise.

However, if the pressure only rises when the boiler is in use then its quite probably the expansion vessel requires repressuring.

 

[spudkey]

sounds like a leak in heat exchanger turn off cold main to boiler to see if pressure stops rising

 

[gas4you]

I never advocate trying to clean out plate HEs. I always only replace with new.

Simple job on a Linea

 

[srj321]

Cheers for all the replies - will test whether the pressure goes up once the main to the boiler is turned off tomorrow. Tends to only creep up throughout the day so as will be out tomorrow and will have no need for hot water will be a good time to test it all.

For my pocket I certainly like the sound of replacing the HE as a simple job - have found it to buy for approx £65 so was wondering how long would it take a decent corgi plumber to actually replace it.

Cheers again for the input.

 

[undercover]

Cheers for all the replies - will test whether the pressure goes up once the main to the boiler is turned off tomorrow. Tends to only creep up throughout the day so as will be out tomorrow and will have no need for hot water will be a good time to test it all.

For my pocket I certainly like the sound of replacing the HE as a simple job - have found it to buy for approx £65 so was wondering how long would it take a decent corgi plumber to actually replace it.

Cheers again for the input.

last one took me an hour with a brew after 30 mins
I'd also recommend that the dhw thermistor is changed at the same time.

 

[arfurrrr]

It could be the gas valve isn`t set up correctly . Have your RGI check/test the gas burner pressures (hi/lo) , before splashing out a load of cash .

Arf