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3.5.5.
Water quality
• Preparing the water system before putting the heat pump into service
For any installation (new or renovation), the water pipes must be thoroughly cleaned. The purpose
of this initial cleaning is to eliminate germs and residue that can cause deposits to form.
In new installations in particular, residue from grease, oxidised metal, and even copper micro-
deposits must be scrupulously removed.
In renovated installations, cleaning should focus on removing sludge and the products of corrosion
formed when the unit was last in operation.
There are two types of methods for cleaning and removing sludge: a high intensity approach that
takes a few hours, and a slower, more gradual approach that takes several weeks. In the first case,
it is essential to clean before connecting the new heat pump. In the second case, fitting a filter on
the heat pump return will capture any loose deposits.
The cleaning performed prior to installation improves performance, reduces energy consumption,
and resists scaling and corrosion on the unit. A professional (water treatment) should carry out the
cleaning.
• Protecting the unit against scaling
Water naturally contains dissolved calcium ions and carbonates that cause scaling (calcium
carbonate) to form. To prevent excessive deposits, take precautions with regard to the water used
to fill the unit: 8°f < TH < 15.1°f.
When the installation contains softener, the equipment must be inspected frequently to check it
does not discharge any chlorine-rich water into the network: the chlorine concentration must always
remain below 50 ppm.
To prevent the build-up of calcium deposits (such as on exchange surfaces), the unit should be
brought into service slowly, starting by operating at a low power with high primary water flow.
Water must be added during the life of the heat pump. The new water adds scaling to the water
system. To avoid this, it is important to check that the hardness of the water added does not exceed
TH<5°f. The amount of fill water plus the amount of make-up water added during the life of the unit
should not be more than three times the water capacity of the heating system. If this guideline is not
followed, complete cleaning (descaling and cleaning) is necessary.
If it has excessive scaling, the unit's settings for operation and for water treatment must be adjusted.
Adding a large amount of untreated water always contributes a significant amount of scaling. To
monitor this and to detect problems, a system water meter must be installed.
When carrying out work on the installation, do not drain it completely. Only the sections of the circuit
concerned need to be drained.
•
Protecting the heat pumps against corrosion
Corrosion can affect the iron components used in heat pumps and heating systems,, directly related
to the presence of oxygen in the water heater's water. Dissolved oxygen that enters the unit when it
is being filled for the first time reacts with the equipment materials and quickly disappears. Without
refreshing the oxygen through significant contributions of water, the unit might not experience any
damage whatsoever. However, it is important to follow the sizing rules and installation guidelines
in order to prevent oxygen from continuously flowing into the heating water. From these rules, we
have:
- Preferably an expansion vessel with a membrane rather than an open expansion vessel that
allows direct passage.-
- Internal pressure with the unit of more than 1 bar cold.
- Remove leaky (permeable) components that are letting out more gas than as if they were sealed.
If the guidelines above are followed, the unit's system water has the proper characteristics to last a
long time: 7.5 < pH < 9 with a dissolved oxygen concentration of < 0.1 ppm
If there is a chance that oxygen could enter the unit, you must take additional precautions. Adding
an oxygen scavenger (ex. sodium sulphite) is highly recommended. We recommend directing any
water treatment questions to specialists, which can provide the appropriate treatment based on the
characteristics of the installation, and a monitoring agreement with a guarantee as to the results.
In the case of a unit where the water is in contact with heterogeneous materials, for example, if there
01-07-2022
AHP60 26/32 kW - Installation, Use and Maintenance
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