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Principles of commissioning and operation of heating systems
In modern heating systems is important to take care of heating water quality, install, commisioning and operation.
Otherwise rapidly and clearly show problems. The aim of this part is to warning about rules which are related to
this problematic.
1) The quality of filling and heating water
Valid norm dealing with water quality ČSN 07 7401 is binding for heating systems with heating power below 60kW
and maxima heating water temperature of 115°C. Water adapted by this norm perfectly responds to heating
systems with lower power. Water modification by the norm is not realistic at small heating systems (flats, family
house).
It is advisable to follow the following recommendations:
* use of water with hardness lower than 5,6 N0 and conductivity lower than 0,5 mS/cm
* circulation water pH set by corrosion resistance of used materials in heating system
Steel corrosion:
- at pH higher than 8,5 is satisfactory
- at pH higher than 10 is insignificant
Copper corrosion:
- at pH higher than 10 is consiredable
- at pH from 8,5 to 9 is reasonable
Aluminium corrosion:
- at pH higher than 7,5 is considerable
- at pH from 6,5 to 7,5 is acceptable
* when drinking water is used, it is necessary to apply anto-corrosion chemicals for water hardness stabilisation
* if there are used more kinds of material inside of heating system (copper, aluminium, steel) is required use of
special chemicals for a specific system
*at least once a year (before heating season starts) is needed to check chemicals content and replenish
as needed
2) Rinsing of new heating system
Norm ČSN 06 0310 about design and install of central heating according to article 132 prescribes rinsing of
system before testing and commisioning. Sense of this obligation is to remove impurities from heating system.
That means mainly mechanical impurities, fats,oils, residual products after welding and soldering. The exact
procedure is not defined and therefore we recommend:
* for rinsing use softened water (max. 5,6 N0), if it is possible; drinking water without treatment is usable as well
* add suitable, not foaming, degreasing detergent into water for remove of fats and oils (only cold or hot water is
not able to remove fats and oils)
* set maximal water flow (all reduction valves are open, maximal circulator power)
* heat the heating system by half-power of boiler to ca. 6°C (slow heating up is particularly important when is not
used softened water for minimization of limescale)
* after heating up keep system in operation for 30 minutes
* when system cools down under 40°C, you can drain water in compliance with the law on waste water
* clean up filters of mechanical impurities
* immediately begin to ful fulfilling the system by permanent filling
3) Settings of pressure parameters of expansion tank
Chosen volume and pressure parameters of expansion tank are very important for long-term and trouble free
operation of heating system. Necessary volume of expansion tank is selected by ČSN 06 0830. Insufficient
volume and pressure ratios leads to repeated aeration and corrosion of heating system. The heating system
designer should guarantee the right volume of expansion tank. To installation company we recommend to set
pressure parameters as following. User should to check this parameters once a year.
Gas overpressure (Pn) in expansion tank
* overpressure setting must be done with empty expansion tank (without water)
* pressure Ps of expansion tank is defined as sum of pressure of static water column Pst and 0,2bar
(pressure Pst is defined as difference betweeen expansion tank and highest point of system -> 1m = 0,1bar)
Heating (filling) water pressure (Pf) settings
* enable seamless filling of system by opening all regulation valves
* filling water pressure Pf should be about 0,3 - 0,5bar higher than gas pressure Pn in expansion tank; filling water
pressure is checked in cold state by manometer at water side after bleeding
