My vaillant ecotec boiler is showing a high pressure?

Yeah cheers for advice, I just bled a rad down and it's gone back to 2 bar. Many thanks

Carl0sFandang0
March 2010

the chances are that the expansion vessel is not big enough to accommodate your CH system water. As a rule of thumb, the expansion vessel should be approximately one tenth the volume of the system volume, for example if the system volume is 100litres, the expansion vessel needs to be at least 10litres.
If the system volume is say 130litres,with an expansion vessel of 10 litres. The system will over pressurise. The solution is to fit an additional expansion tank,which will resolve the problem.
Note check that the static pressure is around 1 Bar (with heating off) and no more than 3Bar (with CH on). If the static pressure is higher than 1Bar the problem will be exacerbated. I suggest you ask your plumber to fit a pressure regulator that will govern the incoming mains water to a maximum of 3Bar. This means the maximum pressure at the filling loop is 3Bar, which is unlikely to damage the boiler. The system should be completely purged of air. If the indicated boiler pressure is in excess of 1Bar. The pressure can be reduced to 1Bar by gently opening a radiator bleed or drain valve and closing the valve when the desired static pressure is reached.

Chris Gale
October 2007

the chances are that the expansion vessel is not big enough to accommodate your CH system water. As a rule of thumb, the expansion vessel should be approximately one tenth the volume of the system volume, for example if the system volume is 100litres, the expansion vessel needs to be at least 10litres.
If the system volume is say 130litres,with an expansion vessel of 10 litres. The system will over pressurise. The solution is to fit an additional expansion tank,which will resolve the problem.
Note check that the static pressure is around 1 Bar (with heating off) and no more than 3Bar (with CH on). If the static pressure is higher than 1Bar the problem will be exacerbated. I suggest you ask your plumber to fit a pressure regulator that will govern the incoming mains water to a maximum of 3Bar. This means the maximum pressure at the filling loop is 3Bar, which is unlikely to damage the boiler. The system should be completely purged of air. If the indicated boiler pressure is in excess of 1Bar. The pressure can be reduced to 1Bar by gently opening a radiator bleed or drain valve and closing the valve when the desired static pressure is reached.

Chris Gale
October 2007

the chances are that the expansion vessel is not big enough to accommodate your CH system water. As a rule of thumb, the expansion vessel should be approximately one tenth the volume of the system volume, for example if the system volume is 100litres, the expansion vessel needs to be at least 10litres.
If the system volume is say 130litres,with an expansion vessel of 10 litres. The system will over pressurise. The solution is to fit an additional expansion tank,which will resolve the problem.
Note check that the static pressure is around 1 Bar (with heating off) and no more than 3Bar (with CH on). If the static pressure is higher than 1Bar the problem will be exacerbated. I suggest you ask your plumber to fit a pressure regulator that will govern the incoming mains water to a maximum of 3Bar. This means the maximum pressure at the filling loop is 3Bar, which is unlikely to damage the boiler. The system should be completely purged of air. If the indicated boiler pressure is in excess of 1Bar. The pressure can be reduced to 1Bar by gently opening a radiator bleed or drain valve and closing the valve when the desired static pressure is reached.

Chris Gale
October 2007

then bleed a rad to bring it down.

hi-spec plumbing
August 2007