I have biasi 24s Me90, boiler is losing pressure quickly, There is no leaks or issues with radiators. Pump and air pressure switch is working fine. The diverter valve is not making pressure i suppose. The pin in diverter valve is not coming out to turn on the switch. Called a boiler repair guy who suggested that its a diverter valve. Do I need to change the diverter valve? Diverter valve makes pressure in the boiler or what? Any help will be much appreciated. Thank you.