Controlling The Flow Rate Through The By-Pass; Initial Heating Phase; Regulation Phase - BWT 100M Montage- Und Bedienungsanleitung

7.4

Controlling the flow rate through the by-pass

The amount by which the pool water temperature is raised on passing through the titanium heat exchanger
depends on two factors :
• the flow rate (adjustable)
• The temperature difference between the incoming heat transfer fluid and incoming pool water.
The higher the ambient temperature, the higher the temperature of the heat transfer fluid at the heat
exchanger inlet.
The temperature difference between the heat pump inlet and outlet will vary according to the machine's operating
conditions.
• it will decrease with decreasing ambient air temperature and/or increasing pool water temperature
• it will increase with increasing ambient air temperature and/or decreasing pool water temperature
To adjust the flow rate though the by-pass loop, the machine must be running at full power, that is to say, the set point
temperature is more than 3°C above the pool water temperature for at least 20 minutes. Under these conditions, and
only under these conditions, the by-pass should be adjusted to obtain a delta T of
Nota Bene :The efficiency of the heat transfer between the heat transfer fluid and the pool water will decrease if the
heat exchanger is encrusted (limescale, etc.) or even partially obstructed. This may prevent the pool water
from reaching the set point even with the bypass valves configured to minimise the flow rate through the bypass loop.
7.5

Initial heating phase

The first time that the heat pump is started up, or when it is restarted at the beginning of the pool season, the pool
water will need to be heated by several degrees to reach the desired temperature (set point).
In addition to minimising heat loss from the pool (see page 28), it is frequently necessary to leave filtration running
24 hours a day so that the heat pump can also run 24 hours a day in order to heat the water to the set point within an
acceptable time.
When these precautions are taken, the initial heating period could last between 2 and 4 days depending on the day
time and night time temperatures (although the air temperature may be high during the days, nights are often quite
cool at the beginning of the season).
7.6

Regulation phase

On the contrary to the fixed speed (50 Hz) compressors equipping conventional On/Off heat pumps, the speed of an
inverter compressor will vary between 30 and 88 Hz depending on the heat pump's operating conditions.
Thus, while the ambient temperature is low, or when the heating demand is high, the Inverter compressor will
at high speed (between 50 and 88 Hz). Inversely, when the heating demand is low, notably when the pool water
temperature is around the set point, the inverter compressor will run at low speeds (between 30 and 50 Hz).
Operating at low speeds, the noise level is extremely low, the COP is optimised and the service life of the compressor
is extended.
Nota bene: The heat pump only runs while filtration is running.
The length of the daily filtration cycles may prove insufficient for the heat pump to correctly maintain the pool water
temperature around the set point.
In this case, lengthen the filtration cycles and cover the pool while it is not in use to limit heat loss from the pool.
CHAUFFAGE & DÉSHUMIDIFICATION 2020/11 - Indice de révision : I - Code : 33340
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