PowerFlush and Salamander SESI scale inhibitor

[Pw123]

Hi,
I have a Potterton Combi 80 boiler which has been working perfectly until few weeks ago. It started to lock itself out which meant that I had to reset the boiler. Since I have the boiler cover from British Gas, I called them to investigate the issue. What the guy suggested was that it is due to the sludge and we need powerflush. We had issue with boiler last year when BG replaced one of the fans in the boiler.

However, we have a Salamander SESI scale inhibitor installed as well and my queries are:

- what is the likelihood of sludge when I have scale inhibitor installed? Does the scale inhibitor prevent sludge in anyway?
- could the sludge cause the boiler to lock itself out?

Many thanks

 

[FD Powerflow]

Sesi only changes the scale's ability to adhere to a surface (supposedly) if scale has built up on your primary heat exchanger it will form unevenly and insulate the surface of the metal meaning the water wouldnt heat up as efficiently and although the HX itself is hot enough the water isnt and it could lock out.

It could also happen with magnetite (sludge) build up in a system, try getting a jam jar and bleed some water out of a drain cock somewhere low on the system. Chances are if the water is black/brown you need to have a powerflush as this is iron solubalised in the water, as soon as this meets fresh oxygen you will end up magnetite build ups which can block boilers/pipework/rads.

 

[Destroyer2813]

If you do need a powerflush get some indepent local plumbers to give u a quote should be much cheaper than BG

 

[Pw123]

Thanks FD powerFlow and Destroyer2813.

One additional question - my rads (except the tower rail), have one outlet on the centre of the bottom rather than usual two (i.e. one each side). Can these be powerflushed? Or am I looking at the situation where I may have to get the rads changed?

Thanks again

 

[warrington]

I don't want to say BG is wrong, but when your boiler lock itself, there should be lock out led, and if you follow troubleshoot according to led, flashing lights, you will have an idea about possible problems. Does it lock out on heating side or hot water etc. you should notice. did you have any kettling problem before it started to lock out? do you have any banging starts?

 

[Pw123]

Hi Warrington - thanks for your reply. I noticed something very strange today. We had the Central Heating switched off for most of the day today. However, late afternoon when my wife finished using the domestic hot water, the boiler continued to run even though there was no demand for either DHW or CH. I checked to see if any of the hot water taps have been left on but this was not the case. However, the boiler was running almost in full power even though there was no demand. On one occasion boiler locked itself down and I had to reset it. On other occasion, I had to turn one of the hot water tap briefly and then turn it off and then the boiler stopped working. Also, when this happened, there was a banging noise that came from the system but I couldnt make out from where.

Thanks