Very loud Vaillant water heater, video provide

[Rahman]

I have a solar powered water heater, on some days its extremely loud for a few hours.
Most days it's silent and there's no noise when the sun goes down.

First video is with the cover on when it's making the most noise
View: https://youtu.be/AgFyb34Ej9s

Second video when it calms down a little, I've taken the cover off
View: https://youtu.be/pTM6eV3weRg


Please help, is it quick fix it needs looking into?

 

[ShaunCorbs]

When was the last time you had it serviced (the solar)

 

[John.g]

It needs topping up and the Expansion Vessel pre pressure checked as the pressure should be 1.5 to 2.5 bar, the pressure gauge is not indicating any pressure?.

 

[ShaunCorbs]

Just too add Not with water

 

[Rahman]

We did get it serviced two years ago but the homeserve plumber hasn't seen this type of solar water heater before.

@John.g which pressure do u change, one at the top where is making the noise.
Do I just turn the blue lever to get the pressure to 1.5 - 2.5?

 

[ShaunCorbs]

We did get it serviced two years ago but the homeserve plumber hasn't seen this type of solar water heater before.

@John.g which pressure do u change, one at the top where is making the noise.
Do I just turn the blue lever to get the pressure to 1.5 - 2.5?

you haven’t had the solar system serviced

prob the gas boiler or unvented water cylinder

best to get someone who specialises in solar systems out asap

 

[John.g]

We did get it serviced two years ago but the homeserve plumber hasn't seen this type of solar water heater before.

@John.g which pressure do u change, one at the top where is making the noise.
Do I just turn the blue lever to get the pressure to 1.5 - 2.5?

No, the solar system is filled/charged with a mixture of glycol/water which will remain in liquid form down to ~ -25C, a charging pump is also required so as Shaun suggests, get somebody in who can look at the whole system. Briefly, a solar system works by comparing the temperature in the roof panel(s) with the temperature in the bottom of the cylinder and it brings in the solar circ pump with a temp differential of ~ 7 to 10C and stops it when that differential falls to ~ 3C.
For general interest you may care to post the model etc of that unit.