Hello WDIK
There is no charge in the accumulator and there is no non return vave in the system. There was no non return valve in the old system and it worked very well!
hotshot
I have just renewed the plumbing in my Narrowboat and the hot water only comes out in "spurts" with the pump "pulsing"the water through the Vaillant water heater.The cold water runs fine with the pump running continuous but hot water only trickles.The heater is firing up the same as the pulsing...