we test a new installed heat pump ... and we the next tests

Test no 1
- Domestic Hot water only - all Ok

Test no 2
- Only heating ,
for about 30 sec the H pressure is at normal level (1.5 mpa)
after 30 sec pressure is growing from 1.5 to 2.5 mpa in about 20 sec
temperature of the water at exit (out air cond) around 25 C
when temp of the water at exit is 30C (out air cond) H press is around 2.7 mpa

no air in the system
water flow ok for both heat exchangers

Test no 3
- Only cooling,
in this case the pressure is growing to 3 mpa in about less than 5 sec,

Test no 4
- domestic hot water & heating
when of hot water reach the set temp, the heat pump try to action the 4 way valve and the reaction is as following >>

- the H press reach 3 mpa in a very short time (3-4 sec)!!! & we heard a whistle for a long time ... we stop manual the heat pump


Test no 5
- domestic hot water & cooling

when the heat pump starts is happening that the H press reach 3 mpa in a very short time (3-4 sec)!!! & we heard a whistle for a long time ... we stop manual the heat pump

some advice ?