Hansa shower faucet

[bgt277]

I am owner of a Hansa shower faucet that I'm having problems with:

The unit was purchased back in 1997

From the sales receipt: 86360023 Royal Brass Hansmat Thermo Shower

I recently replaced the control cartridge

No longer have the instructions which may have come with the unit.

Cold water works fine, hot water no pressure

Could someone help me tp understand this unit I can send photos of the unit

Thanks in advance

Ben Thomke