Low pressure in my ecoTEC combi boiler

[deanow]

Morning guys, hope you can help.

i had warm water from my hot tap and checked boiler which had low pressure. i turned the 2 plastic taps like i have done after bleeding rads but the pressure just keeps dropping and has now caused the boiler to turn off. does it matter which tap needs to be turned first? the braided hose was still attached by the plumber when installed last year. never had this problem before.
many thanks

 

[fingers123]

The system is losing water somewhere or the pressure release valve is dumping water due to too much expansion of water.

First isolate the central heating from the boiler by closing the CH flow and return, located just under the boiler. Then pressurise system and run boiler. If you still loose pressure then the boiler is at fault.

If you don't loose pressure the fault is in the CH circuit. Try this test and report back results.

 

[deanow]

damn, that sounds expensive . do you know a rough cost for each scenario? is it a common problem?
thanks