"Resin Coated" aluminium HEX on Glow Worm/BG 330+

[JohnD]

BG came round today to quote me for a new boiler, I have my eye on a Stainless HEX but they offer this one with an Aluminium exchanger with a "resin coating" to prevent it being attacked by the water (I live in a hard water area but have a softener).

I notice it only has a 1 year guarantee, unlike the Viessmann which I think guarantees the Stainless HEX for 25 years

by dimesnsions and description, it seems to be a rebadged Flexicom hx

Does anyone know what these resin-coated exchangers are like?

 

[gas4you]

personally I won't touch any make with an aluminium HE.

I always quote for s/steel. I've seen to much crud at each annual service on alumimium HE boilers

 

[petit_pablo]

Not really seen much on these resin coated h/ex's but the 330+ is basically a flexicom with some bells and whistles

 

[The Baker]

Are you on one of Centrica,s (BG) plans? If so what difrence would any warrentee make to your monthly payout to Centrica (BG)

Tim

 

[superdupergasman]

personally have had quite a few of the old stainless H/E being very noisy and having to be changed, they had debris inside them and must not have been flushed properly at install. NEVER had a leaking one tho!!!!

That Alu H/E has been around a while in some of the other glowworms and seems to be not bad.

 

[JohnD]

@ The Baker

yes but I might not stay.

My position is:

A Stainless item tends to last a long time and stand up to water without corroding. Take my stainless cooking pans, for example. Plenty of flame, water, salt, acids but they polish up like new after many years of use.

Aluminium alloys tend to corrode when exposed to water, heat, flame, hot gases. Take my aluminium Espresso machine pressure vessel, for example. Tarnished black, and the inside is grey and crusty.

Which material do I expect to last better?

It is easy to give a 25 year guarantee on something that isn't going to fail.

If you make something that you don't expect to last very long, you don't give a long warranty on it.

Do I want to buy something that the manufacturer has great confidence in, or something that he doesn't?

 

[superdupergasman]

Are you on one of Centrica,s (BG) plans? If so what difrence would any warrentee make to your monthly payout to Centrica (BG)

Tim

If you buy a boiler from BG, you get free homecare 200 for 1 year and this can be extended for upto 5.

If you have a boiler not installed by BG the boiler H/E warranty makes no difference as there are plenty other things to go wrong on a system.

 

[gasmanben]

the 25 year warranty is a waste of time. its not going to fail, they know it and market it as a selling point.
everything else on the boiler can break through wear and tear, although the veissman is a reliable solid boiler.

 

[JohnD]

and today I got a good quote on a Worcester Bosch 15Ri, also with Stainless exchanger, which from what I hear is another good one.

I was on the verge of signing it, but the Viessmann 100 Compact engineer hasn't sent me his price yet (he surveyed yesterday)

decisions, decisions, I love them.

Any views on one or the other boiler? I feel quite happy with either of the people, and they are both happy to install it as I wish and said they liked that I had done my homework and know what I want. Well-established local firms based in my small town, one small, one big.

 

[mickyg]

BG came round today to quote me for a new boiler, I have my eye on a Stainless HEX but they offer this one with an Aluminium exchanger with a "resin coating" to prevent it being attacked by the water (I live in a hard water area but have a softener).

I notice it only has a 1 year guarantee, unlike the Viessmann which I think guarantees the Stainless HEX for 25 years

by dimesnsions and description, it seems to be a rebadged Flexicom hx

Does anyone know what these resin-coated exchangers are like?

Its a decent heat exchanger, shouldn't get any problems with it. One benefit it has over some of the stainless heat exchangers is larger bore water ways, so much less likely to get noise/blockage issues. I'm fairly sure the design is similar in principle to the energysaver combi heat exchanger(don't confuse the heat only energysaver-completely different) which was designed by a dutch company. Ask anyone with an energysaver"combi" if they ever needed a new heat exchanger. I've never changed one.

 

[Razor900]

Are you sure the worcester 15Ri has a stainless hex? Thought they were aluminium/silicon

 

[scatmanjohn]

Are you sure the worcester 15Ri has a stainless hex? Thought they were aluminium/silicon

Correct.

 

[JohnD]

(scuttles back after studying the brochure and website)

It is. How on earth did i get the idea it was stainless? Maybe i picked up some wrong info off the web. Or do WB make some SS boilers in a different range?

that's a disappointment... when thh guy was here today he said he would be recommending a Vaillant or a Worcester, and I said that I was pleased because they both make boilers with SS exchangers, and said how keen I was on SS.

Are Vaillant more expensive or something? I only need a 15kW conventional, vented boiler to go onto a fully pumped, vented system with tank-fed cylinder

 

[Gasguru]

Pitching Stainless against Aluminium (and vice versa) is futile.

They both have there merits however, there is a vast difference between the way manufacturers utilise the material in their heat exchangers. Corrosion can result from either materials if not accounted ffrom the outset. Plymouth harbour have plenty of examples of crevice corrosion on the stainless fittings on their architectural rigging.

For example the Viessman stainless coil is infinately better that the stainless Giannoni. The parrallel coil bundles in the Giannoni will easily lodge sludge in the invert of each coil....perhaps leading to noise. Despite the servicing headache with some Worcesters their heat exhangers are infinately better than some Baxi, Potterton, Ideal etc. Some aluminium heat exchangers may in fact be more tolerant of sludge since it will collect in the lower regions where the combustion products are of substantially lower temperature ie zero chance of kettling etc. Every design has its pros and cons.

As for a coating on the Glowworms I would treat it with suspicion...more to do with marketing carp. Long term life cycle testing by manufacturers is no longer carried out (since cheaper models are launched at an ever increasing pace). Glowworm have made some terrible boilers.

The only quality aluminium treatment I know of is on the Buderus commercial range. These have a very unique design and I would have confidence in their claims.

As for warranties...caveat emptor..read the small print. Most of these long warranties are a fallacy. Most customers will not have the boiler properly serviced yearly to comply and most "servicing" is not carried out sufficiently well. It's very easy for a manufacturer to take a water sample and deem the system contaminated and void the warranty. In addition this process will be dragged out forcing the customer to relent their claim and just fit a new boiler.

My personal view of a reliable heat exhanger would be to use a traditional copper primary heat exchanger with a stainless low fin recuperator combined with a fully pre-mixed burner. It would achieve Band A rating but no manufacturer will enlist that design due to the higher cost entailed.

 

[gas4you]

The Vaillant would be the Ecotec Plus 415.