Condenser Under Performance - Bosch DOMESTIC HOT WATER HEAT PUMP Technical Manual

7.3 Condenser under performance

The condensing process is normally stable, and will not cause any major disturbances on the system performance.
The evaporator performance can have influence in the condenser performance, and the problems are usually
manifested as an increased pressure head.
Check Points:
- Check the installation visually (refrigerant and water circuits are connected in counter-current mode
with the refrigerant inlet at the top.
- Check the condenser for temperature variations on the outside
If gas is trapped, or water channels are obstructed, inside the condenser, there will be large surface
temperatures differences.
- Check temperatures on the water side
Make sure that the entering and leaving water temperatures correspond to the design conditions. If the
temperature difference is higher than the design conditions, the water flow rate has been reduced.
- Check the amount of sub-cooling
Too much sub-cooling will block the heat transfer surface from the condensing process and thus
increase the condensing pressure. This may indicate that the system has been overcharged. Release
refrigerant charge until a reasonable value (2k – 5k) is achieved.
- Check the compressor
The condenser capacity is always set by the compressor. If this one is working improperly, the
condenser capacity will be affected.
- Check the suction pressure at the compressor inlet
Use the compressor data to compare the capacity design data
- Check the pressure drop over the secondary side of the condenser
Pressure drop is proportional to the flow rate squared.
- Check the pressure drop in the discharge line
If the filter located after condenser and before expansion valve is saturated and the pressure drop is
too high, replace component.
- Check the discharge temperature
Compare with design conditions supplied by Bosch.
Page 52 from 63
Pict.59 – Position of the bulb and insulation
6720649497 SM HP270-1 2012/09 en