CH Problem after flushing

[robertbullen]

Additional info: Could I block the expansion pipe and fill up with a hose from the bottom? Would this force the sludge into the expansion/header tank for scooping out. Remember, when filling from the bottom, dirty water flows from the expansion pipe into the expansion/header tank.

 

[chrishutt]

It's the vent pipe, not the expansion pipe.

You could try that, but if the feed & expansion pipe is solidly blocked, the excess pressure in the system might do some damage. Usual solution to blocked F&E pipe is to cut it open near the connection to the flow/return pipe, inspect and mechanical clean, replace sections of pipework badly blocked.

 

[robertbullen]

What's strange is that water flowed Ok from the tank into the CH system from the tank into the downstairs radiator for a few minutes before getting blocked.

So, let me get this right. The vent pipe is the one hanging over into the expansion tank. What is the pipe feeding the system from the expansion tank called?

 

[chrishutt]

the feed & expansion pipe

 

[robertbullen]

Some more info. I've identified the expansion and feeder pipes and the both come from the same point just under the pump. The feeder pipe is only 6-7 feet long. I guess the feeder blockage must be in here somewhere. Is that the case?

Also, I tool one of the rads off the wall today and flushed it with a hose. The water coming out was black (working under poor outdoor light tonight) but not "sludgy". This rad has suffered from being cold. Do you still think sludge is my problem.

Also, that bubling was coming from the cylinder again just now, not a boiling bulbling though.

 

[chrishutt]

I've identified the expansion and feeder pipes and the both....

Bob, I just explained that the pipe is called a vent pipe, not an expansion pipe, and what do you do - you bleeding well call it an expansion pipe!

Is it perversity or stupidity?

 

[robertbullen]

Habit. Someone told me many years ago it's an expansion pipe. It stuck. Don't worry, there's a guy at work called Elliot. I've called him Wayne for 2 months. It's just the way my brain works.

Anyway, what do you reckon? I know you're thinking "call a plumber". Just right now I've got a washing machine down and just moved house, I'm skint.

 

[chrishutt]

OK Wayne, if you think you've got a blockage in the F&E pipe, it's probably close to the connection to the flow pipe.

I suggest to drain system to just below level of this connection and then cut all 4 pipe near the F&E and Vent junctions with the flow pipe. On the pump side you can just undo the compression joint to the pump valve, but the others will need to be remade with compression fittings (for ease of future inspection and cleaning).

You will probably find that the pipework generally is lined with corrosion deposits and the F&E pipe may well be completely blocked. Try cleaning this grot out, and if you cant do this, you could replace with a section of new pipework.