Table of Contents
Advertisement
4
Preparing for installation
NOTICE
Residue in the pipework can damage the system.
Residue and particles in the heating system impair the flow rate and lead
to faults.
▶ Before connecting the indoor unit, flush the pipe system to remove
any foreign bodies.
4.1
Water quality
Water quality in the heating system
Heat pumps operate at lower temperatures than other heating systems
which means that the thermal de-airing is not as effective and oxygen
levels are never as low as with a system incorporating an electric/oil/ gas
boiler. This means that the heating system will be more susceptible to
corrosion when exposed to aggressive water.
Preventive actions are required if the heating system require recurrent
filling or where a heating water sample don't show clear water.
Preventive actions can be to supplement the heating system with a
magnetite filter and a de-airing valve.
Actions when the heating system requires recurrent filling:
▶ Check that the volume of the expansion vessel is sufficient to the
heating system volume.
▶ Replace the expansion vessel.
▶ Check the heating system for leaks.
A system separation with the help of a heat exchanger may be required if
the limits in table 3 can not be achieved.
Do not use any water additives except for a non-toxic pH-enhancer
and keep the water clean.
The limits stated in table 3 are required to ensure the output data and
operation of the heat pump throughout its entire service life.
Water quality
Hardness
Oxygen content
Carbon dioxide, CO
2
-
Chloride ions, CL
Sulphate, SO
4
Conductivity
pH
Table 3 Water quality
Additional water treatment to prevent lime-scale deposits
A poor quality of the heating water promotes the formation of sludge and
lime-scale. This can lead to malfunctions and damage of the heat
exchanger in the heat pump. According to the current guideline VDI
2035 "Prevention of damage in water heating installations" and
depending on the degree of hardness of the filling water, the system
volume and the total output of the system, water treatment may be
required to avoid damage due to the formation of lime-scale.
If the limits for water hardness stated in table 3 are exceeded, the
performance of the heat pump will deteriorate over time. If this
performance degradation can be accepted, the limits in figure 1 are
required to ensure the operation of the heat pump throughout its entire
service life.
Compress Hybrid 3400i AW – 6721861825 (2023/08)
<3 °dH
<1 mg/l
<1 mg/l
<250 mg/l
<100 mg/l
<350 μS/cm
7,5 – 9
Heat pump
Total alkalinity
output [kW]
/ total hardness
of the filling
water [°dh]
Q < 50
Requirements
according to
figure 6
Table 4 Table for heat pumps
V [m
3
]
2,60
2,40
2,20
2,00
1,80
1,60
1,40
1,20
1,00
0,80
0,60
0,40
0,20
0,00
0
5
Fig. 6
Limits for water treatment in heat pump systems
A
Use completely de-mineralized fill water above the curve,
conductivity ≤ 10 microsiemens /cm.
B
Use untreated tap water below the curve. Fill according to the
drinking water regulation.
H
Water hardness.
w
V
Total water volume: fill volume of the heating system and top-up
volume over the service life of the heat pump.
If the total water volume is above the limit curve in the diagram (Fig. 6)
suitable measures are required for water treatment.
Suitable measures are:
• Use of fully de-mineralized fill water with a conductivity of ≤ 10
microsiemens / cm.
To prevent oxygen from entering the heating water, the expansion vessel
must be adequately dimensioned.
When installing diffusion open pipes, a system separation with the help
of a heat exchanger is required.
Water treatment products
NOTICE
Material damage due to contamination in the system!
Dirt particles from the system can damage the unit and impair efficiency.
▶ Observe instructions of the guideline BS7593 for the treatment of
water in warm water treatment systems.
▶ Do not use frost protection/glycol products.
Preparing for installation
Maximum fill and top-up water
3
volume V
[m
]
max
Requirements according to
figure 6
A
B
10
H
[°dH]
W
0010036248-002
7
15
Advertisement
Table of Contents
