Aqualisa shower cartridge

I have a systemmate 2000 manufactured in Oct 2003 it is a model ASC 2179, I need to replace my shower cartridge it is a Aqualisa would I use a gravity, combi, or a HP thermo cartridge they have a orange,pink or green ring on them.
Thanks
Mike

It could be either of the last 2.
Why not just check the cartridge you have?
Mike

I did check it, its the Orange gravity feed one, the problem is I have had 2 of these one in the bathroom and one in the bedroom both started to leak , I replaced the Bathroom one with a Myra shower unit a few years ago and cannibalised the other unit for the bedroom one, but it didn't last, now one of the children is coming back home and we need the second shower.
I was wondering which unit would be correct because my limited knowledge suggests the gravity one might not be correct for the system.. but to be honest I didn't know, but the Systemate 2000 isn't a gravity system ..
I don't want to spend £100+ on the wrong cartridge.

Mike

Well the HP would be the one as DHW at mains pressure.
Combi's have a lesser flow rate.
Is your DHW pressure high, as in the same as the cold?
If it is and really forceful then the HP would be the one.
If not give Aqualisa a call who are very helpful.
Mike