oil combi problem

[nicktracey]

We have an oil combi that works our hot water system. the most upper radiator is the towel rail in our bedroom. This towel rail is faulty and I need to change the valve and t connection to the electric feed.
Is it as easy as turning off the boiler and draining down, changing the faulty valves and t connection and refilling?
Do I need to drain down thw whole system or just enough to work on the towel rail?

 

[Boilerman2]

Just drain enough water to reduce the system pressure to zero, put an old towel down as you take out the old valve (do one at a time) you should not need to do a full drain down for this!) it goes without saying to turn of the power supply to the boiler first!

 

[nicktracey]

thanks for that. Do I just guess how much water I need to drain down or is it a case of watching until it goes down to zero?
And is ti easy enough to fill up ?

 

[Boilerman2]

Pressure guage to zero, and the water will slow to a dribble at the drain point filling up is easy provided you know where the filling loop is and how to use it!