Fernox DS-3 in combi boiler

[Alphas]

Is it safe to run Fernox DS-3 in my combi boiler? I’ve tried DS-40 but is didn’t cure the kettling/boiling water sound.

Boiler is a Potterton Lynx 2.

Cheers

 

[ChrisR]

Yes. Close all rads except one and circulate hot, then less to flush out afterwards.
You could also try Boiler Silencer.

 

[Alphas]

Thanks. I did try boiler silencer and it worked for a bit but problem came back

If this doesn't work I'm going to get a new boiler as I've tried pretty much every conceivable (from a DIY’ers perspective) method to stop it from kettling and I’m sick to death of it now!

 

[Agile]

It might help to explain exactly what the problem is and then we can suggest the best solution !!!

The professionals here do sometimes try to help when they are not biting each others backs!

 

[Alphas]

It might help to explain exactly what the problem is and then we can suggest the best solution !!!

OK.. Here goes..

System: About 13/14 years old and comprises of a Potterton Lynx 2 combination boiler and 8 radiators.

Problem: boiler sounds like it is boiling the water internally inside the heat exchanger and there are lots of hissing and “ticking” noises coming from it. These tend to fade away after the boiler has been running for 3/4 minutes but are very annoying and disconcerting (especially as the boiler is sited directly above the toilet!!)

I’ve tried lots of methods to try and resolve this which include: running Sentinel X400 through the system, doing a mains powerflush through all the radiators and boiler, running Fernox DS-40 through the entire system and fitting one of those magnaclean devices as well as adding Fernox noise silencer. All of which have helped and radiators heat up very quickly and there are no cold spots but this “hissing and ticking” still remains. There is also Fernox Super Concentrate Protector running in the system at the moment.

My gut feeling is that we live in an extremely hard water area (right on the south coast) and in the last six years we’ve lived in the property various TRVs and other work has been carried out on the system and it has just been filled up at the filling loop with mains water and no inhibitor added! (yes I know, hindsight is a wonderful thing!!). We have already had to replace 2 radiators due to rust. I think the only thing stuck in the primary heat exchanger now is limescale, which is the reason for this post.

Do you think that DS-3 is going to sort it or is it curtains for the (otherwise fully functional) boiler..

 

[corgiman]

i would not do it due tot he boilers age, dont think it will do anything

I cannot remeber if these have an all heat exchanger or not or i would suggest some serious chems to do it

CHange the poor old thing

 

[Alphas]

Have a what heat exchanger? what difference would it make?

 

[ChrisR]

I think he meant Ali - aloo minny yum
Copper in copper innit?

I'd try something harsh, but maybe not while the weather's cold!

 

[corgiman]

I did mean ally

sorry

if its copper then nasty stuff should be ok but as chris says it is cold out there brrr

 

[Alphas]

Yes.. it is bloody cold out there!!

According to the service and installation manual it is copper heat exchanger.. and I quote:

"The Lynx 2 has two completely separate heating systems embedded into a copper heat exchanger"

So does this mean i'm good to go with the DS-3? or is there something better I can use??

The boiler is sounding worse by the day and wont be long until it starts going into lockout again (overheating) so am willing to take the risk!!!