Added Corosion inhibitor, Now boiler wont work

[tigerjimbo]

Hi. Tonight I've drained the f and e tank in the loft enough to add some corosion inhibitor to the system and change a dripping ball valve. I filled the f and e tank again and bled the radiators. Downstairs rads had virtually no air in them, however, upstairs took absolutely ages to bleed.
On restarting the boiler to test the heating again it lit and stayed on for about 20 seconds before going out. There was a slight gurgling sound which seemed to travel back into the f and e tank. I have bled everything I can think of with no joy.
The system is an open vented system with a small f and e tank and an Ideal boiler. The flow (i think) has an automatic air vent which seems to be working correctly.
I'm sure it's air trapped but I'm at a loss how to rectify it. The boiler isn't "kettling" as far as I can tell. I have seen that happen before but this is different.
The system seems to be in pretty good order. It was installed in 2001 and has had regular inhibitor added. The water when I drained down was fairly clear.
I've bled the pump too although it's one I haven't come accross before. It has a large black knurled knob in the centre where you would normally find the bleed screw. It unscrews fairly easily but doesn't remove completely. Got some air out but no water.
Any help would be gratefully received.

 

[Bambergaspipe]

Sounds like an airlock. is your system piped up in 10mm pipework?

 

[Agile]

It sounds as if your feed pipe is partially blocked.

To get it going I would pour water down the vent in an effort to fill the system quickly.

It will probably auto fill over night but it might not!

Tony

 

[tigerjimbo]

No, the main flow and return is 22mm from the boiler reducing to 15mm to the radiators. I feel sure you're right about air in the system. Any bright ideas?
Thanks.

 

[tigerjimbo]

Sorry chaps. The speed of your replies took me by surprise!

Thanks for the advice Tony. The f and e tank is alrady full. Would it work putting a hose into the cold feed and waiting to see it pushed out of the vent pipe? Just thinking about the logistics of getting water into the vent pipe!

James

 

[Bambergaspipe]

Trace the cold feed from your F&E tank to where it connects to your system. Usually in cylinder cupboard, usually on a tee connection, whatever the configuration, tap this area slightly with a hammer, this may clear the partial blockage as Agile has said. If not you may have to remove the cold feed, clear the blockage & re-pipe it

 

[Agile]

It sounds as if your feed pipe is partially blocked.

To get it going I would pour water down the vent in an effort to fill the system quickly.

Tony

 

[Bambergaspipe]

It sounds as if your feed pipe is partially blocked.

To get it going I would pour water down the vent in an effort to fill the system quickly.

Tony

Be a long time pouring water down his vent to fill his rads won`t he? Make sure you use a big kettle, also depends on where his vent is connected won`t it? The only way to solve the problem of a blocked cold feed if this is the case will be to chop the pipework, remove the blockage & re-pipe. Unless of course you want to keep climbing into your loft with big kettle every time your system requires topping up

 

[ChrisR]

Disconnect the outlet from the iso valve and connect a flexy tap connector (1/2" will fit) going to 22mm speedfit, which you shove on the vent once you've cleaned the scale off it.
You can then fill the system from the mains - you never know what might come up the feed pipe.

 

[Bambergaspipe]

I know how to backfill Muppet. This will not alter the fact that his cold feed will have to be cleared The easiest way is to try tracing the cold feed to where it is connected to the system& doing what I have suggested. No need for for backfilling which is only a temporary measure.

 

[Bambergaspipe]

Disconnect the outlet

What outlet?

from the iso valve

What`s an iso valve?

and connect a flexy tap connector (1/2" will fit)

What`s a flexy connector?

going to 22mm speedfit,

what`s a speedfit?

Next time you post, try less `plumberspeak` to impress your peers & talk more in laymans terms to help the poster, after all that`s why you`re here & giving up your precious time isn`t it

I seem to remember not too many years ago when you didn`t know what a `speedfit` was.

 

[tigerjimbo]

Thanks for the advice. I'll give it a go and let you know how I get on.

 

[gas4you]

Did you open any zone valves manually when filling the system? Have you checked the pump is working? They can sometimes stick when system is drained down.

 

[tigerjimbo]

Dave, funny you should mention that!! I didn't open any valves manually and I did check that the pump was spinning. However, I couldn't get any water or air from the pump so therefore assumed there was an airlock or blockage elsewhere.

A friend in th trade came around and tried the backfilling, (amongst an hour and a half worth of other stuff !)as a precursor to me cutting into the cold feed pipework, with no joy. As a last effort the pump was re-tried and "prodded" with a screwdriver which caused it to spin at a huge rate of knots. It would appear that despite appearances and sounds to the contrary, the pump was sticking.

Many thanks for all of your help. Spot on Dave, shame I couldn't read your post until after it'd been sorted!