Do you have to drain the system in order to change a two way valve in a central heating system?

Question

Needs changing as it tends to stick when changing over from heating to domestic water.

Answer 1

An electrically operated valve can be un-freed as follows...... Remove actuator head by removing 2 screws exposing the actual valve itself. With a pair of pliers turn the slot many times, this will free-up the valve, replace head.
NO NEED TO DRAIN
Make sure you have inhibitor in the system, this prevents black rust (magnetite) which clogs valves.

Answer 2

It is very strange or careless not to fit a drainage valve to the system. Turn off the mains tap. If it is a house with more than one floor, you can drain it by opening the air-bleeder tap on top of the radiator that is on the lowest level of the building. Gravity will force the water out if you also open the air-bleeder tap on the top floors (wait till the level is down or water will also gush out from it too). There will still be water left in the radiators on the ground floor and if you want to drain it completely, you will have to get a pump and insert a small tube down the air vent to suck it out. All this will take time, and I would take the opportunity to change one/two of the valves for one with a drain.

Answer 3

yes, absolutely. Sure you need to change it? It may just be seized after months of disuse. They quite often seize at this time of year. Remove the actuator and try to work the valve back and forward with a spanner, pliers or similar. You can also test the actuator while it is disassembled like this.
A squirt of WD 40 can work wonders- don't be too hasty to replace this component!!

To replace the valve you need to drain the system.

Answer 4

NO NO NO! Depending on the make/ model of valve, you probably just need to change the powerhead or possibly just the motor.

Answer 5

yes. unless you have a freezing kit.