read the FAQs and follow TO THE LETTER, post back when you have done this
Good call GG
2) REPRESSURISING THE PRESSURE VESSEL
Turn the boiler off at the mains.
Find the PV valve which looks like a car tyre valve with just a threaded part sticking out and is often red. They can be accessed from the top of the boiler or behind the front drop-panel. Some boilers such as Ravenheat can be impossible to access!
If water comes out when you press the central pin, you need a new PV
Drain enough water from the system to drop pressure to Zero. Drain an extra 10 litres of water out, or leave the draincock open if none will come. This may draw air into the system.
Use any (car or bike)air pump to pump up the PV to eg 10 psi (0.7 bar).
Remove and refit pump to see how much pressure drops when you remove it and inevitably lose some air.
If the pump doesn't have a built in gauge, pump it up a bit high, then keep taking readings with a push-on gauge. Every time you do, the pressure will drop a bit.
During this phase it is IMPERATIVE that water or air is allowed to escape from the heating system as it is pumped out of the PV. Otherwise system pressure will resist your pumping and give a meaningless reading.
If you aren't sure, let some more water out when you have the air pressure at the right level. If that makes the air pressure drop, pump a bit more and release water and so on, until it doesn't.
The PV may be say 10 litres. If it was full of water you have to displace all of that water from the system side by your pumping up the air in the vessel. That's a whole bucket of water!
Top boiler pressure back up to 1 bar and switch boiler back on.
Some air may have got into the system so you should bleed rads too and then recheck the pressure.
DO NOT let water into a hot boiler. Let it cool first.
DO NOT let water in too quickly. 20 seconds for 0.5 to 1 bar should be OK.
DO NOT take the pressure above 1.5 bar- even if the system is warm as the switch may have stuck.
DO NOT allow the pressure to go too high when refilling Turn it off early to see if the gauge keeps rising a bit.
NEVER use the Pressure Relief Valve to let water out of a system – it will leak afterwards!
