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FAQs

We’re here to help!

Q
What is the advantage of Combimate compared to other water treatment systems?
A

British-designed and manufactured, Combimate is a widely recognised and thoroughly proven hard water scale inhibitor that has delivered protection to hundreds of thousands of UK homes since its launch in 1987.

Combimate does not use magnets or any electricity in its effective anti-limescale operation and is easy to install with minimal subsequent maintenance.

The product is supported by a professional UK-based customer service team with first class technical advice and spares support.

Find out how Combimate works – click here to watch our video

 

Q
Having installed Combimate, will I need a separate (non-treated) drinking water supply?
A

No. Combimate is not a water softener. Water softeners generally use salts, so softened water requires a separate supply because of the increased salt content.

Q
What is Combiphos?
A

Combiphos is the name of the crystals used inside the Combimate unit.

The Combiphos in your Combimate is a harmless food-grade polyphosphate compound which is used to prevent the formation of scale deposits in your hot water system. It utilises the phenomenon that minute concentrations of polyphosphates are sufficient to inhibit the deposition of scale onto metallic surfaces.

Because of its phosphate and silicate content Combiphos also inhibits corrosion by forming a thin protective layer on the metal surface.  A Combiphos concentration of 2-3ppm (parts per million) is sufficient to achieve both of these effects.

Existing hard scale, i.e. calcium carbonate, cannot be easily removed by Combiphos.  In these installations, Combiphos will prevent further scaling up.  Limescale can build-up in all untreated hot water pipes and systems whatever material they are made of, including plastic.

Find out how Combimate works – click here to watch our video

 

Q
What do the Combiphos crystals do the water?
A

Combiphos which, when in contact with water is released in very small quantities, is sufficient to keep the mineral ions in suspension.

This action prevents the formation of scale while retaining the health benefits of the natural minerals contained in hard water.

As mains water presses through the Combimate unit it flows through the Combiphos crystals.

The calcium within the water attracts the phosphate within the Combiphos crystals – in so doing, the minerals are kept in suspension as the water flows through the hot water system, preventing the calcium sticking to hot surfaces and leaving a deposit of limescale.

Combiphos also coats the inside of the pipework, boiler heat exchanger and appliances with a non-residual, microscopic, protective coating.  This again prevents scale-causing minerals from accumulating and aggressive soft water from corroding the system and appliances.

The action of the Combiphos does not soften the water but retains the health benefits of the natural minerals contained in hard water.

Q
Is Combiphos safe?
A

Yes, Combiphos is classed as a ‘food grade’ additive which conforms to European Standards EN1208 and World Health Organisation standards as a safe additive to drinking water.

You can install a Combimate directly on the rising cold water mains and safely bathe in or drink the water supplied.  Combiphos is safe for water in contact with babies, tropical fish, pets and skin conditions.

Q
Can I taste it?
A

No, Combiphos is completely tasteless.

Q
Does it smell?
A

No, Combiphos is odourless.

Q
Will it discolour my clothes?
A

No.  Combiphos has no effect at all on fabrics.

Q
Will Combimate protect my central heating system?
A

In a central heating system, Combimate will only protect the boiler via the mains water feed into the heat exchanger.  However, the ‘closed loop’ of the heating system (radiators, pipework etc.) is not protected.

Combiphos coats the inside of the pipework, boiler heat exchanger and appliances with a non-residual, microscopic, protective coating to prevent scale-causing minerals from accumulating and aggressive soft water from corroding the system and appliances.

Find out how Combimate works – click here to watch our video

 

Q
How do I know when the Combiphos crystals need replacing?
A

Combiphos will reduce in effectiveness in proportion to the amount of water passing through the Combimate unit.  This will vary depending on individual consumption, so not every situation will be the same – hence, we recommend the Combiphos is replaced annually.

Q
How can I buy Combiphos refills?
A

To purchase Combiphos online, please click here  

Alternatively, Combiphos can be bought from leading plumbing and building merchants with Trade stockist retail outlets located across the UK.

Combiphos is retailed via Trade stockist outlets in boxed 800g jars.  Online Combiphos orders are supplied in 800g bags for ease of postage.

Q
Does Combimate need maintenance?
A

Apart from the annual replacement of the Combiphos crystals, Combimate requires no other maintenance.

Q
Does heat affect the Combimate?
A

Yes.  If the Combimate is located in a warm environment (e.g. an airing cupboard) or near a heat source, the Combiphos crystals will dissolve at a faster rate.

Ideally Combimate should be installed at room temperature with a cold water supply, located at least 450mm from any appliance or local heat source to prevent water in the dome from warming and accelerating the dissolution of the Combiphos.

Q
Can I replace the Combiphos crystals myself?
A

Yes.  Replacing the Combiphos is easy if the procedure is correctly followed.  See ‘How do I change the Combiphos crystals?’ question below or refer to the owner’s manual supplied with the Combimate unit.

Q
Do I need a plumber to fit the Combimate unit?
A

Fitting the Combimate requires a basic competency level of plumbing skills and equipment. However, for peace of mind we recommend a professional plumber installs the product.

Find out how to install a Combimate – click here to watch our video

See James Lawrence of Plumberparts installing a Combimate – click here

 

 

Q
Who makes Combimate?
A

Combimate is a product made by Cistermiser Ltd – the leading manufacturer of water management systems. Cistermiser has been designing and manufacturing a range of high quality, cost effective, water efficient products in the UK for over 35 years.

Combimate was launched in 1987 and quickly became the product of choice of plumbing and heating professionals looking for an effective limescale prevention solution.  Over 30 years later, Combimate is still proudly made in the UK and continues to protect hundreds of thousands of homes by preventing limescale formation.

For more information on Cistermiser Ltd click here

Combimate and Cistermiser Ltd are part of Davidson Holdings – Davidson Holdings Ltd owns and manages brand-leading companies in the lightside building products sector.

For more information on Davidson Holdings click here   

Q
Where can I buy Combimate?
A

To purchase Combimate online, please click here

Alternatively, Combimate can be bought from leading plumbing and building merchants with Trade stockist retail outlets located across the UK.

Combimate is available in models for either 15mm fittings or 22mm fittings and your required size should be specified at point of order.

Q
My Combimate is due for its annual re-fill, but there are still plenty of Combiphos crystals inside it. Do I still need to change the Combiphos?
A

Yes.  To maintain the treatment effectively both the quantity and quality of the crystals needs to be kept at an appropriate level.

Combiphos reduces in volume in proportion to the amount of water passing through the Combimate which will vary according to individual circumstances.

Combiphos immersed in static water for more than two months without through-flow will start to deteriorate and will eventually form into a solid mass.

We recommend replacing the Combiphos annually.  This provides a simple routine for a range of typical domestic applications.

Q
I have fitted a Combimate, but why do I still have scale in my showerhead/kettle/taps?
A

Combimate is not a water softener.  Combiphos reduces the scale deposits by keeping the minerals which cause scale in a dissolved and suspended state at higher temperatures.  As a result most scale causing minerals pass through the system instead of forming scale deposits.

Unlike softened water, water that passes through a Combimate remains unchanged, so hard water treated with Combiphos but left in a kettle may still create a build-up when the water evaporates.  However, this residue is more paste-like in consistency rather than hard scale and is easily wiped away with a cloth without need for chemicals.

Q
How do I change the Combiphos crystals?
A

To remove the old Combiphos remove the cover from the Combimate (this automatically isolates the water supply) then open the unit by removing the cover, filler plug, retaining ring and clear dome.

Remove old Combiphos.  Reassemble in reverse order but place new Combiphos through the top prior to replacing the round plug.  Clean the ‘O’ ring seal before replacing the ’O’ ring with new (supplied within the replacement Combiphos jar).  To read our Installation Guide, click here

 

 

Q
Do I need to turn off the water supply to change the Combiphos?
A

No, when the Combimate cover is removed the mains supply is automatically isolated.  This feature also works as an emergency mains-supply cut-off device – much quicker and easier than trying to find your stop-cock!

Q
I want to change the Combiphos but how do I undo the metal ring?
A

Having removed the cover you should then remove the red filler plug to relieve the internal pressure. The aluminium ring should be not more than hand tight, although after 12 months it can very occasionally ‘bind’ on the plastic thread.  If it will not release using both hands we recommend using a filter band or ‘boa-constrictor’ type tool available at DIY outlets.  When replacing the ring it should only tightened manually.

Q
I have just changed the Combiphos and now have a leak! Why?
A

The most likely cause is that the large ‘O’ ring is in the wrong position or a small piece of Combiphos is preventing the ‘O’ ring from seating correctly.

Q
Where is my Combimate serial number?
A

The Combimate six digit serial number is located on the top of your product box – on the tamperproof seal (see Picture 1).

The serial number can also be found on the side of the Combimate base once the cover has been removed (see Picture 2 & 3).

Q
Are there any videos about Combimate?
A

Yes, please find the following video links below.

  1.  Find out how Combimate works – click here to watch our video
  2.  Installation of a Combimate – click here to watch our video
  3.  See James Lawrence of Plumberparts installing a Combimate – click here

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Whether you need help with product support or installation advice, our dedicated support staff are on hand today.