Combi-care scale inhibitors. Do they work?

[caiss4]

Today my local heating engineer turned up to give the oil-fired boiler its annual service. Whilst chatting with him I pointed out this cartridge like unit hanging off the pipework around the hot water tank and asked him if it was something that required attention.

He immediately identified it as a Combi-care scale inhibitor and that it should be changed annually. Shame he hadn't spotted it before as it's been sat there for 5 years now!

He reckoned it would cost about £30 to replace and he'd sort it out this week. Anyway I thought I'd do a search to see if that price was about right and came across some DIY forums where a few stated that they were useless.

Now as far as I can see this is only on the cold water inlet to the hot water system and I had noticed some scaling of shower heads etc (we are in a hard water area)but before getting sucked in to yet another recurring annual cost merry go round I thought I'd ask what the experiences and opinions were on here, particularly from the professional camp. Is it worth shelling out £30 extra per year or not?

[Arthur Jackson]

The combi-care is effectively a polyphosphate doser.
They prevent the scale from forming on surfaces, essentially.
Yes, they work, but the little bleed hole in them sometimes blocks so it's important to give it a bit of a service when changing the cartridge.

[ss64ii]

I use the Combi-mate Cistemiser- change the balls once a year myself-gone from using a filter jug for the water and de-scaling the kettle to throwing the filter jug away and doing nothing.
About £13 for the bottle of balls and an O-ring off ebay and only need changing once a year.

one link for the unit but loads out there -

http://www.google.co.uk/products/catalog?q=cisterm...

[Simpo Two]

ss64ii said:

I use the Combi-mate Cistemiser- change the balls once a year myself-gone from using a filter jug for the water

How did you plan to filter out something that's in solution?

[anonymous-user]

I'm surprised your heat exchanger has lasted for 5 years in a hard water area! Mine scaled up in less than a year from new, but has been fine for last 5 years since fitting Combi-Care, which I replaced with a Cistermiser last year when changing kitchen.

[Rickyy]

I've no experience of these as I live in a soft water area, but out of interest what pipe is it fitted to? You said you have a hot water cylinder, so not a combi? Cold feed to the cold water cistern perhaps?

[caiss4]

I'm no expert in this area but I have a mains pressure hot water system (no header tank). The combi-care unit is fitted to the hot tank cold water supply, not the heat exchanger circuit through the boiler.

[Arthur Jackson]

Polyphosphate has been used for this for years. Micromet used to hang in a little net bag in the top of cold water cisterns in the roof and, of course, Calgon is promoted heavily to keep your washing machine element clean.