Daryl hydra senta 401

[Atr1958]

Hi to all, new to this site so please bare with me.
Just installed a replacement thermostatic cartridge into the hydra senta 401 and there doesn't seem to be any graduation from cold to hot. It's either cold or hot. Could it be that I've got the hot and cold inlets the wrong way round?

 

[Julie Street]

Cold always on the right.
If plumbed with Hot on the right you will have the problem you describe.
If it was ok before you changed the cartridge, check with Daryl. Some manufacturers supply special cartridge for shower plumbed incorrectly.
Otherwise you will have to swap pipes over.