Kettling. De-scale. Isolate radiators? Advice please.

[Unklian]

Hi All Again.

Brief outline.
Old Glowworm 40B Can't remember if it's Fuelsaver of Spacesaver.
Cast Iron heat exchanger. 6 radiators. Grundfoss pump.
Converted from Gravity DHW to Fully pumped.
Water nice & clean. (Dosed every 2 years with X100)

THANK YOU ALL for the previous advice about my pipework.
It is now re-plumbed with dedicated feed & expansion pipes.
So much better.

However......I have had to turn the boiler stat down as it has (for years) kettled. Water flow is very good, but it still produces air inside the boiler.
I've searched topics in this forum about de-scaling but can't seem to find an answer to this......

I presume the de-scaling chemicals are quite harsh. Am I better isolating all rads, and only running the de-scaling chemicals round the DHW heating circuit? Keep it in as long as instructed etc. Then, drain the whole system & re-fill with fresh and add Sentinel X100 again. (As is already in the system).

What brand / chemical would you suggest for this task?

Any helpful suggestions?

Ian.

EDIT......THANKS ALL AGAIN For the advice about dedicated feed / vent pipes.
You were all correct. It was the only way to do things properly![/b]

 

[45yearsagasman]

Don't use harsh descale chemicals. Your boiler with a cast heat exch is probably a Spacesaver and could have gaskets which may be effected.
If noise is your only concern and the system is otherwise working well then consider adding system silencer as well as the X100.
Cast iron heat exchangers will not descale like modern s/steel or copper units.

 

[Agile]

X200 introduced at first into the boiler on hot water cycle with the rads isolated will often solve the problem.

It can be left in the system.

Its risky using acidic chemicals on a c.i. heat exchanger although I would use sulphonic acid ( DS3 ) warmed up on a badly scaled top fed HE after giving the customer a risk warning. I would also consider HCl as well.

Tony

 

[Unklian]

45yearsagasman.

Thanks for the advice. From memory, my HE is similar to this:
http://www.heating-parts.co.uk/Product.asp?Prd=009287
So I presume you mean the 2 gaskets between the "finned bit" and the and tanks.
I'll avoid harsh chemicals then. Is the "silencer" a snake oil type thing or a proven additive?
EDIT: Just had a look. X200 is a "silencer"


Agile.

Thanks for the advice. I'll do some research into X200.

1 more thing: my pump is set in the 1st position of 3 settings.
The water seems to go round the system quickly, but will it improve the boiler situation if I pop it up a notch, pushing water through the HE faster?

Ian.

 

[45yearsagasman]

Increasing pump speed may help with reducing noise. A correctly configured system will be ok on speed 2. Try it and add the x200 and see if it has the effect of reducing the hex noise. There is always a possibility of pulling in air, but you will know after running for a few days.
Fernox and Sentinel make system silencer and they are both proven products. I have used it many times and it can sometimes have almost instant result.

 

[Unklian]

Well, I've read up on Sentinel X200 and I'll try to get some tomorrow.
Hopefully, what I plan to do is......

Isolate all radiators, Add the X200 then run it round the DHW circuit.

If it does have an "instant" effect, I can gradually increase the boiler temperature until the kettling just starts then let it run at that temperature for a couple of days then see if I can increase the temperature again.

If it works as suggested, I should (hopefully) be able to run the boiler hot enough so that our house is comfortable in this cold snap.

I WILL come back to the Forum and let people know the result.

Cheers.

Ian.

 

[Unklian]

Just a quick question.

Which way of adding X200 is best?

The "Concentrate gel" injected ito a radiator with a mastic gun,
(Which I've never used before). Close all other radiators then pump round.

or the traditional 1 Litre liquid poured into a partially drained system?
(I was going to temporarily remove the dead leg in the DHW heating loop, partially drain, pour into the "T" with a funnel & re-fit).

I was just thinking the more concentrated I could make it, the better. Rather than just partially draining, pour in the header tank & re-fill.
Or would that method give the required concentration? (only 6 radiators).

Cheers.

Ian.

 

[45yearsagasman]

Either way is OK. Where possible I pour the liquid variety into a partially drained radiator. That way, once the rad is turned back on and the system is run, the silencer is circulating immediately.