Installation of heat pump and domestic hot water tank
21.11.2015
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Z20469
Copyright
2013 by: WATERKOTTE GmbH. Subject to changes.
8.6.7
Flow monitoring
When using water as heat source, the evaporator of the heat pump can be de-
stroyed by ice formation due to lack of water (frost damage). Repeated switching
on of heat pump in an improper forced manner may easily result in total loss. For
this reason, we specify a reliable protective measure against lack of water.
The protective measure consists of two devices that function independently of one
another:
a)
Temperature limit by controller: For this purpose, the controller is configured for
operating mode "Heat source water" This solution allows that:
a warning is generated if value drops below +1 °C and
operation is interrupted when value drops below -1 °C.
b)
Because the measure mentioned under a) cannot react quick enough in case
of sudden lack of water, an additional low water safety device must be provid-
ed.
A low water safety device consists of a float-type volume display with adjustable
limit indicator (limit indicator is a Reed contact).
Function:
The heat pump control switches the compressor on with a time delay to "pump
heat source". The start of the compressor is only enabled if the minimum water
volume is present during the lead time and the limit indicator did not respond. This
device remains active during the entire operation of the heat pump. If water vol-
ume drops below the permissible level during operation, the heat pump is shut
down. This device provides maximum security because it virtually covers all risks,
such as filter contamination, evaporator contamination, overloaded well, etc.
Damages caused by freezing of evaporator result in exclusion of warranty!
8.6.7.1
Filter
To prevent contamination, the media inlets of the evaporator and heat exchanger
must be equipped with a filter (0.8 mm mesh). Contamination in the heat ex-
changer can cause corrosion and - in some applications - freezing of the heat ex-
changer!
8.6.7.2
Cleaning
If the formation of deposits is to be expected (e.g. severe contamination) based on
water quality, cleaning must be performed in regular intervals. Cleaning can be
performed by flushing. The plate heat exchanger is to be flushed with a suitable
cleaning agent in counter-flow direction.
If chemicals are used for cleaning, please ensure that they are compatible with
stainless steel or copper. Failure to comply can result in destruction of plate heat
exchanger!
