Where did I go wrong draining my Combi Boiler System?

[Mr Sparkle]

To drain my system, I attached a hose to the rad drain valve

I then opened up the rads to allow air out

After waiting over 2hrs for the water to drain.. I went to add some inhibitor into my towel rad (by opening the valve on top (not the air side)..

I'd barely added 100ml when the water in the rad shot up all over the floor.

What I want to know is why this happened?

FYI - I never turned off the main water supply... and I live in a block of 20 flats with an individual combi boiler..

Does anyone have any advice on getting inhibitor back into the system in this case?

 

[FiremanT]

Was it not the inhibitor, rather than water, spraying out? Normally a case of pouring in quicker than the rad is allowing the fluid to flow through. You don't need to isolate at the stopcock.

 

[cross thread]

isolate the towel rail, remove the top air plug siphon a litre out and pour in the inhibitor, replace plug open valves to towel rail and repressurise system

 

[Mr Sparkle]

Was it not the inhibitor, rather than water, spraying out? Normally a case of pouring in quicker than the rad is allowing the fluid to flow through. You don't need to isolate at the stopcock.

It was mainly inhibitor, but the inhibitor/water remains by the top airplug

isolate the towel rail, remove the top air plug siphon a litre out and pour in the inhibitor, replace plug open valves to towel rail and repressurise system

Great idea! Thanks

A couple things.. By isolate do you mean 'Shut off the lockshields?'

Also, what can i use to get a litre out?

 

[dilalio]

Also, what can i use to get a litre out?

Nozzle from a spray bottle and squirt it into a bucket or you can use a bit of pipe using your thumb to create a vacuum and bail it out.

Open up the other end (air vent) too as this will make it easier to pour inhibitor in by preventing a vacuum.

 

[Ian H]

When I poured it into mine it all came out because the holes into the towel rail tubes were higher than the bottom of the vent plug. I had to raise one side a bit.

 

[Mr Sparkle]

Nozzle from a spray bottle and squirt it into a bucket or you can use a bit of pipe using your thumb to create a vacuum and bail it out.

Open up the other end (air vent) too as this will make it easier to pour inhibitor in by preventing a vacuum.

In the end i cut a piece of my garden hose (long and flexible)..

stuck this in the radiator and then attached my wet vac to the end of the hose and it drew all of the water out

Your post provided the inspiration, so thank you..

Inhibitor's now in the system and jobs a good'en

 

[dilalio]

In the end i cut a piece of my garden hose (long and flexible)..

stuck this in the radiator and then attached my wet vac to the end of the hose and it drew all of the water out

Your post provided the inspiration, so thank you..

Inhibitor's now in the system and jobs a good'en

The mighty wet vac... Every home should have one