Combimate
How Combimate works
Combimate is a user-friendly domestic scale prevention device that uses
Combiphos, a 100% food grade material whose use is endorsed by the World
Health Organisation, (FAO/WHO ref.7 and EN1208), to prevent scale
build-up and corrosion in combination boilers and other domestic hot
water appliances.
When in contact with water Combiphos is released in very small quantities,
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. Combiphos coats the inside of the pipe-work, 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.
Installing Combimate
There are two possible installations; whole-house supply or single appliance.
Whole-house supply. For this installation Combimate should be plumbed
in after the stop-valve on the cold water supply to the premises.
Single appliance installations - usually to protect the boiler. Combimate
should be plumbed in on the cold water supply pipe. A removable divider
tray reduces the amount of Combiphos required; it should be left in for single
appliance installations and the Combiphos only put in the top half of the
Combimate dome.
Inlet and outlet connections use 15mm compression fittings with a single check valve integral to the inlet valve. These connections can be reversed depending on the direction of the water flow. Vertical, horizontal and
top and bottom entry pipe-work can be used which ensures
easy retrofit installation. Combimate should be installed at least 0·5m from
any local sources of heat such as boilers or hot water pipes.
Tried and Tested
Combiphos is a polyphosphate compound specifically developed to prevent
scale build-up. Widespread use of the dosing technique over many years
around the world has proved it to be reliable and effective.
Health and Safety
Combiphos is tasteless and odourless
and meets the necessary WHO
requirements to be classed as a
'food-grade' additive. The quantity,
size and hardness of the spheres
control the amount of Combiphos
released. Typically this is less than
3ppm (parts per million) of phosphate
in treated water and perfectly safe
for human consumption.
Servicing and Maintenance

Note that Combiphos does not soften water
and its effectiveness may be reduced if
installed at temperatures above 80°C, in
water with Carbonate hardness levels
above 360ppm or at pHs below 6·5.
Combimate is manufactured to high quality standards and is WRAS approved. Over time the volume of Combiphos
in the dome gradually reduces. Routine servicing is limited to ensuring that there is Combiphos in the dome. The
entire Combiphos contents should be replaced at least annually, even if there are Combiphos spheres left in the dome
and irrespective of their apparent condition.
Combiphos is replaced by removing the Combimate cover which is released by pressing the two red buttons on
either side and pulling it forward. As the cover is released a patented integral mechanism shuts off the water
supply allowing access to the Combiphos dome. The dome can then be removed from the body by undoing the
red filler plug to relieve the pressure and then unscrewing the aluminium locking ring to change the Combiphos
spheres.
Cistermiser replacement packs containing 800g of Combiphos, sufficient to re-fill the whole unit, complete with a
new O-ring seal, are available from merchant stockists. The O-ring should be changed each time that the
Combiphos is replaced.
The Combimate De-Scaling Guarantee
If Combimate is installed with a new boiler and the Combiphos replaced annually, Cistermiser guarantees that the heat
exchanger will not scale up. Cistermiser will de-scale any boiler that does scale up within 3 years of Combimate
installation free of charge and refund the cost of the Combimate.
Installation information (English) [PDF Document]
Product overview (English)
F.A.Q. (English)
Combiphos Material Safety Data Sheet(English) [PDF Document]