Central Heating

Boiler Pressure Increasing

Anonymous user 09/03/2024 - 3.18 PM

Hi There, I was hoping someone could advise on the below. - I have a Combi Boiler (Vailant EcoFit Pure 830), roughly 2 years old - Recently had 2 radiators replaced, pressure was fine before this - When system is cold pressure is 1.3 - When Central Heating is on at peak temp, the system pressure goes to 2.5 to 2.6 (irrespective of whatever the cold pressure is, i.e. if i topped the system to 1.7 it still goes to 2.5, and if i bled the system to 1.1 the CH would still go to 2.5 when hot) - If i use hot water only, then the pressure only increases by 0.1 to 0.2 bar - If i use CH AND Hot Water the overall pressure spikes to 2.8 to 2.9, (has never gone above this so far) Diagnostic performed so far: - Had a boiler engineer perform a servicing last week - The Expansion vessel was checked and is correctly pressurised - The PRV is seated correctly and shows no issues - No water leaks inside or outside the boiler - As far as he could see the boiler was working fine, however he mentioned the increase in pressure was a bit higher than he would expect - Filling loops are closed and show no leakage - ALL radiators have been bled and contain no air at all and heat up fully from top to bottom My question is whether the above pressure spike an issue? and any ideas what could be causing it?