Wiring. 3 glow worm 30 hx boiler to get her

[Marty123]

Hi we are heating a swimming pool using Glow worm 30 Hx boilers we have 1 pump fitted to the system
the problem I have is getting the pump to work with all three boilers . I have a fused spur for each boiler what are controlled from a Qe1. Timer . I have tried linking all the pump connections together bye looping them but this did not work. Looking for some help

 

[buckley plumb]

are the boilers linked to a lost header with the one pump .sketch would help