MHS Boilers Ultramax WM 100, Operating & Maintenance Manual, Page: 34 / 50

MHS Boilers Ltd ©
191007
34
In connection with the hardness of the water, a distinction should be made between the following:
a. Temporary hardness:
This is also termed carbonate hardness. Deposits are formed at higher temperature and can be
removed easily.
b. Permanent hardness:
Minerals (for example calcium sulphate) in the water that are deposited due to very high surface
temperatures.
The water hardness is generally expressed in terms of “ppm” and is sub-divided into the following:
Very soft ‹ 50 ppm
Soft 50-160 ppm
Moderately hard 160-250 ppm
Hard and very hard ‹ 250 ppm
The system should contain soft to medium hard water, with the water hardness that does not
exceed 250 ppm at a flow temperature of 80°C and
∆ t 20 K.
Before supplying water, the hardness and chloride value of the system water should always be
determined.
The chloride value should never exceed 200 mg/l.
If the chloride value does exceed this value, the cause should be determined. Compare the
chloride value of the supply water and the central heating system water. If this content is much
higher, and if no materials containing chloride have been added, this indicates evaporation. If the
chloride content is very high, the water is rendered more aggressive. (Can be caused by, amongst
other things improperly regenerated water softener). The system should be flushed clean and
filled with low chloride water.
In order to counter unnecessary wear and tear and blockages due to impurities present in the system,
we recommend the use of a filter system with a mesh size of 100 microns. Always place this
in the return line of the secondary part of the system.
In order to guarantee a properly working system and long life, one should remove suspended and
corrosive particles by installing a suitable filter system.
The periodic inspection including the analysis of the system water and the cleaning of the filters
should be performed.
It is imperative that the system is treated with suitable corrosion and scale inhibitors. The
concentration of the dosage must be monitored and maintained on a regular basis. Failure to comply
with these requirements will render the appliance warranty null and void.