Intergas Eco RF vs HRE

[hard-work]

The Navien NCB- 40LDWE gives a flowrate of 19.1 litres/min. Modulates down to 4kW. Very impressive indeed. Well priced for such spec's and quality. Who needs cylinders with this around?

https://www.plumbase.co.uk/navien-ncb40ldwe-combi-boiler-100010607-4000006
Tech specs:
https://www.plumbase.co.uk/link/1/h041015_32363_t.pdf

 

[Dan Robinson]

Obviouly not limescale......

So Dan please tell me what it is most likely to be, an oxide of aluminium perhaps, maybe a sulphate / sulphide of aluminium.

You're the one that brought up descaling. Afaik it is an aluminium oxide and it builds up here as it does in Holland (who's gas is slightly different BTW).

Degree of build up depends on servicing regime but done properly adds no extra time or cost. If the boiler is condensing massively then it will build up more quickly..

 

[bernardgreen]

Afaik it is an aluminium oxide

Which means the heat exchanger is being eroded.

It seems to build up between first and second "deflector" strips, which I believe were not part of the original design of the heat exchanger but were added later to improve perfromance,

You're the one that brought up descaling

I couldn't think of a word to describe the removal of oxides from a heat exchanger.

 

[Dan Robinson]

Honestly I couldn't tell you but it may well be several things.... @shambolic and @vulcancontinental and @Razor900 will know more.

Where it forms depends on the degree of condensing. Those strips where added in neck in the early naughties to ****** the flue gases. Now we have the labyrinth design which is more efficient but fiddlier to clean.

I have a "special" brush I use for lightly caked heat exchangers. Funnily enough I'm about to go and clean one that is overdue.

 

[bernardgreen]

I'm about to go and clean one that is overdue.

Any chance of before and after photos, ( owner's permission of course )

early naughties to ****** the flue gases.

cannot be turbulate, not enough asterisks

Now we have the labyrinth design

how does the labyrinth design differ from the original ( apparently perfect ) design ?

 

[Dan Robinson]

I have a new heat exchanger at the office will upload it later.

I had used the word r e t a r d the flue gases.

 

[hard-work]

So this crud does not fall into the condensate trap. How long did it take for all that to build up?

 

[Dan Robinson]

That boiler was 12 years old. Flow temp locked at 65. It would have been cleaned out a few years ago though.

 

[hard-work]

So two years of crud. These need an annual service then. That build up must reduce efficiency significantly. Navien is 5 years as they are self cleaning with Americans doing it every 10 years.

 

[Dan Robinson]

Where did I say 2 years?

All boilers need an annual service.

It took 5 minutes to get that hex clean.

 

[vulcancontinental]

Run the ali boiler hot, they don't condense will not need cleaning and still give better efficiency than most stainless boilers in my opinion.

 

[hard-work]

You wrote, Few.

 

[hard-work]

Run the ali boiler hot, they don't condense will not need cleaning and still give better efficiency than most stainless boilers in my opinion.

But more expensive to run.

 

[Dan Robinson]

You wrote, Few.

And?

 

[hard-work]

Means usually two.