Cobi boiler or regular boiler for hard-water area?

Question

Hello DIY-ers,I am buying a house in a hard water area. It has no c/h system and no boiler and I inted to install both. I gather condensing boilers are the way to go these days, but what about the question of combi vs. regular? My experience of a combi in my previous house was that it was constantly furring up dure to the hard water, and I spent a fortune keeping it running. Conversely, my parents had an old fasioned regular boiler and a copper cylinder that never needed any repairs or maintenance. Bleeding the rads once a year was all that was required. So, is there a good argument for using a regular condensing boile rather than a combi? The house I'm buying is a 3-bed semi.Many thanks.Al

John Rumm · Accepted Answer

Al Lights the blue touch paper and stands back ;-)

(cue combi Vs stored system debate - again)

If you stick a phosphate dosing unit (like a "Combimate" for example) in front of the combi then it should not suffer scale problems. That should then bring the decision back to the basic one of which better suits your requirements.

Things like how many people, what's the cold mains flow rate and pressure like etc might be more relevant...

Tim Lamb · Answer

In message , John Rumm  writesI plan to put a conventional ion exchange water softener in front of mine.regards

The Natural Philosopher · Answer

do a cost analysis vis a vis a combi and a softener, versus a mains pressure system boiler without.

However I recommend a softener for all hard water areas. Its not just boilers..shower heads, taps everything furs up and you spend an arm and a leg descaling and repairing.

I dont personally like combis unless space is very limited and there is only a single person or a well in tune couple. Peak flow rates are too low frankly for all but one at a time usage.

And if you get a bigger one instead, it just takes up more space and costs more.

YAPH · Answer

The Culligan SFWH1 whole house unit has many times the capacity of the Combimate and does the same job, and is about £40 from Screwfix including the extra fittings you'll need. Bit more fiddly to fit though (hint: 3/4" bath tap flexi connectors fit the plastic 3/4" bushes that come with it; any other 3/4" Male fittings you try to use on it are liable to strip the threads).

Jon Fairbairn · Answer

Curiously, the installation instructions for my combi say thatsoftening the water isn't recommended.  Any idea why?(at a guess, the extra sodium ions might react with thealuminium?)

Tim Lamb · Answer

In message , Jon Fairbairn  writesFortunately my Veissmann is stainless steel but I also would be interested to learn the reason.regards

The Natural Philosopher · Answer

It reduces the amount they can charge you for spares, and they have a commercial deal with Clag-on?

YAPH · Answer

Though in the (few) houses I've seen with softeners (here in Reading: avery hard water area) I've a suspicion that the 'softened' (i.e.sodium-rich) water attacks some brassware - taps and suchlike.

Al 1953 · Answer

John Rumm  wrote in news:                Thanks, John... I'm not sure of those factors just yet.Alan53

Cobi boiler or regular boiler for hard-water area?

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