The purge valve is the valve on your boiler which is used to remove the water when you need to flush it out. It's important that the boiler purge valve is a good seal to prevent water from escaping. However, this might not always be the case. The boiler purge valve can be replaced if needed, which is common when the rubber seal becomes brittle or damaged.
Replacing the boiler purge valve is actually very easy, with a bit of patience you will be able to replace this valve yourself.
Step 1: Switching Off the Hot water
You should never do work on a hot water boiler while it's still running, especially when you are replacing the purge valve. Make sure that the water heater is switched off. With electric heaters this will be a matter of switching off the circuit breaker, with gas powered heaters you will need to put them into the right mode so that they won't fire up to heat any more water.
Step 2: Identifying the Purge Valve
You now need to identify the purge valve, you should already know where this is. If not, you can look in your owners manual for the boiler.
Step 3: Waiting
Wait until the boiler has gone cold. Whenever you're working with a boiler there's a potential to get scalded. Ensure that the water is as cold as possible before starting work.
Step 4: Draining
Before you can access the purge valve safely you will need to drain the entire tank, this is actually very easy. If you can open the purge valve, then connect a hose pipe and open the valve. This will allow the water to flow out so that you can work on the valve.
If the purge valve has fused shut, you can either try to manually open it using a screwdriver. Or you can simply undo the draining bolt and try to catch as much of the water as possible
Step 5: Checking the Purge Valve
Take a look at the purge valve and decide what to do. If the seals have just gone then it should be possible to replace these without needing to replace the entire purge valve. Replacing the seals is actually one of the easiest things that you can do. Simply open the valve and put in the right seals.
Step 6: Removing the Purge Valve
The purge valve now needs to be removed. Depending on your boiler the process for dong this will be different. Some will be able to be unbolted where as others may need to be ground out. Grinding a valve out is not an easy task and should not be undertaken unless you are confident you can complete the job successfully.
Now you simply need to replace the valve with a new one, the method of doing this will be the same as how you removed the old valve.