HI, ALL HAVE A NEW GLOW WORM 30 BEEN INSTALLED FEW WEEKS. BUT KEEPS LOSING PRESSURE , WHEN HEATING IS ON AND OFF . ITS HAVING TO BE TOPPED UP EVERY HOUR NOW. BIT OF A NIGHTMARE. PLUMBERS HAD FLLORBOARDS UP CANT FIND LEAK.. SO GLOW WORM SENT ENGINEER AND HE PUT NEW PRESS RELEASE VALVE, BUT WHEN...