HOW CAN I FIX MY VOKERA BOILER LOSING PRESSURE WHEN CENTRAL HEATING ON?

Your expansion vessel (big red thing behind boiler)needs recharging. Get car tyre pump, locate valve on top of expansion vessel and connect. Manually open PRV (lift operating lever)to depressurise system. Pump up till air pressure is 10 or so psi, you will have to let out several litres of water via the PRV as you do this. It will take longer than you expect. Then repressurise system. No more hot/cold pressure variations. Try googling.

c
October 2009

first chesk that your filling loop is switched off. as this may be letting by and filling the sytem too much. outside of that and if you have just switched the heating on for the first time... there may be some dirt in the system that has gotten caught in the pressure release valve and jammed it open.... im not technical in this at all... so i guess the cheapest route in the long run is call out your local bandit, sorry plumber....get your wallet on the ready, loosen your belt and get some lube so it dont sting too much. wish you luck... let me know how that lube works out for you ;)

danny
October 2009