Hi I have a problem with my system. When I run the system in cold mode just controller and pump its fine. If I try to run it on hot mode gas boiler using leisure battery new just for ignition of boiler. The controller shuts down showing low battery. If you run engine and battery is charging it runs fine We have run volt meter on battery and controller shuts down as soon as it hits 13ams it wont run with hot on bellow 13 amps. Any thoughts.