Geyserwise Max pump icon receiving correct Volts but does function fully

Hi Guys

I'll try to keep this short and simple as possible. I have a geyserwise max (150L geyser) with collector tubes on the roof with the geyser in the attic and a freshly installed 3 kW element. I've had technicians at my house to connect my black power supply as we had an issue with water not getting hot even with element switched on. We thought the black power supply was the issue but Geyserwise themselves confirmed that there was nothing wrong with it. Anyways the techs installed the power supply and found out the element has gone. They installed new element as stated above and everything was good (so i thought). The techs made their last checks and found out that the Pump receives the correct Volts but when they switch it on it doesn't. He did mention that it could be the pump thats faulty and needs to be replaced (at this time he didn't had a pump on him and money wise i wasn't able to do so). But before this, the pump was working on a regular and before the element gave in. We were running on Solar and the water came out close to pipping hot. I just don't understand as to why it's not the same now. We leave it on solar for the rest of the day after reaching 65C with the element but the temps keeps dropping and the pump icon only appears now and then but is most of the time off.

Can anyone explain what's happen or maybe have more suggestions for me? I'd appreciate your input and i hope i made sense with the above.

Thanks