New boiler fitted but pressure keeps dropping

JohnB47

Did the installer do a powerflush? I've heard that this can cause problems - i.e. leaks. When my boiler was replaced, using the existing pipework, the installing company said they'd had problems with powerflushing and now did only chemical flushing.

nofoollikeold

1. A power lush can identify problems with pipework and joints, and may even cause leaks.
2. However, power flushing machines run at relatively low pressure  but high flow rate.  In consequence, any weaknesses identified are latent within the system and would have later been discovered by higher pressure sealed systems. 
3. Combis and most system boiler installations pressurise the system to about 1.3 bar, whereas a traditional open vented system only hold a pressure of about 0.3 bar in a normal two storey house.  
4. It is generally better to identify and resolve the problem after the power flush and before the new boiler is installed.  The resolution can be undertaken by the person doing the power flushing or the boiler installers.