Unvented cylinder question

[SavageW]

Replacing a leaking unvented,customer had two Ariston unventeds working in tandem eg one cold main split to two pressure reducing valves,shared dhw draw off & balanced cold,secondary returns,flow an return shared but only one Honeywell 2 port that then split to each primary flow of the cylinders coils. I’m querying wether it should have two Honeywell two ports one for each coil?

 

[ShaunCorbs]

yes need two two ports as one could be upto temp and the other isnt

 

[SavageW]

Cheers Shaun,il fit additional tomorrow when I go back