Hard water area - scale problem

[cdg]

I have fairly recently moved to an extremely hard water area. Thanks to the developers of this new build not knowing or caring about this fact has cost me one heat exchanger for a PowerMax 140.

I have been advised to fit a scale inhibitor for what should be half the price of a HE (about £100 + vat).

I've been told an Aqua Dial Scale Inhibitor would do the job but is this good for the job. We're just off the M4 and the water is extremely hard (water filters in the kettle last 3 weeks!). If so, how often should it be replaced and when would I know it was due?

Hope someone can save me another HE. Thanks

 

[Gasguru]

Probably find no one's replied because there is no diffinitive answer.

I'm not aware of any test standard these devices abide by.

I have fitted scale inhibitors if the manufacturers instructions advise but thats more to prevent the customer coming back to me if there is a scale problem in the future.

I assume you are looking at the ceramic type at that price. The polyphosphate crystal types are popular but users rarely replace the crystals after a few years.

If scale is a real prroblem why not install a water softener instead? Pricy but the running cost (salt) is offset by less shower cleaner etc .

 

[Agile]

You say that you are "just off the M4" but your profile shows that you are in Yorkshire!

Surely you must be aware that the M4 does not go to Yorkshire ???

Bracknel and Reading are fairly hard water areas but I look after two combis in each area which have no scale reducers and have no scale problems. I have maintained quite a few boilers in Reading and I have NEVER seen any with a scale problem even without reducers.

I have to conclude that properly maintained and operated a good combi boiler does not need any scale device.

I have seen a few Worcesters in London which is not very hard wnich have been so badly scaled that there was no flow at all from the hot tap. That is due to the design not hard water!

Tony

 

[cdg]

You say that you are "just off the M4" but your profile shows that you are in Yorkshire!

Surely you must be aware that the M4 does not go to Yorkshire ???

Ah - forgot to update profile. Sort of spend time between the two. But you say the M4 doesn't run through Yorkshire. Jeez - can't have been at that meeting when that was discussed.

How good is your geology then? Apparently there is a vein of limestone running right through where we are (M4 corridor) and it causes horrendous problems especially around Bath > Swindon. Like I say, a Brita filter lasts no more than three weeks in the kettle before there's scale on the element.

I have the old HE and it's caked in the stuff - not helped probably by having the DHW set to 24 hours a day with the PowerMax which has a HW store but I've changed that now. Still the problem remains.

 

[Onetap]

Good for 120,000 litres according to Aqua-dial. Check the meter reading.
I don't know if the water hardness has an affect on this, the manufacturers would be able to tell you. The water company would be able to tell you the hardness of your supply.

 

[croydoncorgi]

I have a theory about Power-Maxes and limescale:

(in fact, applies to any heatstore device)

The heatstore in a Powermax is normally held at 80+ degrees, about the 'critical temperature' when 'temporary hardness' is chemically changed and limescale will form.

When water is flowing through the coil and heating up just before coming out of the hot tap - there's no problem: there's not enough time for any deposition to occur. Trouble is when the flow stops: the water still in the coil gets to the same temperature as the heatstore and any hardness in it deposits over the (several) hours before a hot tap is used again.

This time-delay means that magnetic scale-reducers willbe USELESS: the effect that they have is SHORT TERM and as soon as the salts in the water have 'reverted', limescaling will occur.

I believe 'early' Powermaxes came usually fitted with Siliphos scale reducers, which need a new cartridge every 12 - 18 months. More recent models have a built-in anti-scale device but I don't know what it is or how effective.

If you have a siliphos gadget, make sure the cartridge is refilled / replaced regularly.

It is possible to descale the HW coil of a Powermax but time-consuming and potentially messy.

I'd very much like to hear reports of effectiveness (or otherwise) of inbuilt antiscale gadgets and, particularly, if anyone has used a magnetic-type scale reducer SUCCESSFULLY on a heatstore.

 

[oilman]

And to qualify for the "SUCCESS" label, you will have had to remove it and demonstrate it scales up without it. Too many wooly claims are made following non-rigorous tests.

Combimate is possibly a better alternative than Aquadial, as the flow of water through the device is less likely to get blocked. There is only a tiny hole for dosing in the Aquadial.

 

[croydoncorgi]

My mistake....
I thought we were discussing the Powermax with a heating coil permanently fitted inside the cylinder. But it looks like yours is the one with the external heat exchanger, which can probably be more easily swapped than descaled.

On the face of it, I can't quite see why scaling should be a problem on the Powermax 140 configuration: the DHW pump should only operate to circulate hot water from the cylinder through the HX when a hot tap is open. So in principle the HX should be cold when not in use and therefore should not scale up. Maybe a real Powermax expert can enlighten us

 

[a jeffries]

we are powermax experts and have found the ONLY conditioner to work is called a combimate dual fit, they are guranteed to work and its the only thing we as a company would recommend.
our advert is in the find an expert and po12 postcode

 

[cdg]

Would we be looking at between £100-200 for the job inc VAT roughly?

 

[a jeffries]

we would come to bath and supply and fit a combimate for 269 inclusive

 

[Softus]

our advert is in the find an expert and po12 postcode

Oh good - you've paid for an advert so we have to put up with references to it in the plumbing forum.

__________________
Always so desperate for work we'll travel anywhere

 

[a jeffries]

no when you specialize in a product you have to be willing to travel because if you stayed local there would be no point specializing as there isn't enough powermax's so yes we do travel about 2 hours in every direction from gosport which is a large area with lots of powermax boilers, and thank you for taking the time to notice the advert .

 

[Softus]

thank you for taking the time to notice the advert .

Hollow and insincere gratitude if ever I heard it. I haven't looked at your advert - I was commenting on your posts within the forum, which are basically adverts in themselves.

 

[Agile]

If the Powermax store holds system water at say 70 C and circulates this through the plate heat exchanger then when a slow DHW flow stops the system water will be mostly still close to 70 C and could cause the scale in the secondary to be deposited.

Its all very well having a polyphosphate water treatment but the one I saw today had not been touched since the boiler was installed during 1998. Of course it did not matter because it was in London and the combi properly controls the DHW temperature to below the scale deposition temperature.

Tony