Open system, no pressure but f+e is full

[slippyr4]

evening all,

Recently moved into a new house. CH and DHW have been a bit noisy( air noises, sloshing sounds) so this evening I have set about bleeding some rads.

Bleeding one of them, initially a fast flow of air but this tailed off to nothing ( like when pressure drops to zero in a sealed system).

Now the boiler has gone into lockout after some knocks and bangs which I expect is not enough water.

I've been up into the loft and the header tank is full of murky water.

Is there any explanation other than a blocked feed pipe from the header tank? Any tips for clearing the blockage?

Thanks

Slip

 

[muggles]

Almost certainly a blocked feed. Best solution is to cut it out and re-pipe it

 

[slippyr4]

B*gger. not ideal since my wife is overdue. Oh well.

Rather than repipe like for like, I think converting to sealed will be the way to go.

Thanks for your help.

 

[75pete]

You can always try ; Have a look at FAQuestions, shows how you can flush ( if it's not a total solid blockage ) the feed pipe.
FAQ12. Thanks to Chris

 

[Razor900]

Almost certainly a blocked feed. Best solution is to cut it out and re-pipe it

+1 much quicker than converting to sealed

 

[bernardgreen]

Check to see there is valve some where along the feed pipe from the tank to the radiator pipe works.

Previous owners may have have closed it to avoid damage should the house have been left empty for a while during the sale.

 

[muggles]

Some boilers shouldn't be converted to sealed systems, so don't think that's automatically the answer

 

[slippyr4]

This boiler can - potterton suprema 80l. Needs a bypass, filling loop and expansion vessel.

Ultimately I plan to go unvented DHW and a newer condensing boiler so it might make sense when redoing a load of pipe work to future proof it a bit.

Anyway, I don't fancy this one myself ( even though I did all the plumbing (except boiler)) in my last house. This is tight, 28mm and looks a hassle to me.



F/e is the 15 on the left, which is the return.

 

[ollski]

Combine the feed into the vent if its 22mm.

 

[JohnD]

get yourself a strong magnet. The blockage is likely to be black iron oxide, which is attracted to magnets, possibly hardened with limescale.

Hold the magnet to the copper pipe. Most likely any blockage will be where the F&E pipe tees onto the main pipework. Sometimes it is possible to open a joint and poke it with a wire shirthanger, if you don't mind hard lumps circulating round your pipes. Normal practice is to identify and cut out the section of pipe and replace with new.

Having cleared the blockage, fit a system filter and do at least a chemical clean which will reduce the risk of it happening again, and will remove some sludge and sediment.

 

[slippyr4]

Thanks for all the input, your advice has been invaluable in getting me going again.

I managed to back fill the system via a hose pipe on a drain cock, until water was coming out of the vent pipe. There is still a lot of air in the system, but there is more water than the other day, and it's got me back running.

A magnet sticks to the reducing tee shown in the photo above.

I am suspecting that the blockage is also impeding the flow around the main loop as well. It took quite a lot of fiddling to get the pump wet and start pumping.

No lockout since though, so there is obviously enough water in the boiler.

I have my plumber coming on Monday, to decide what to do. I think we will probably end up re piping most of what is in the airing cupboard. The cylinder is too small and not insulated. I'd like unvented but my supply is 15mm so it's not an option unless I get Anglian water and a spade out. So realistically I will use this as the opportunity to change to sealed, upgrade to an insulated bigger cylinder and change to S plan while I am at it (I've got two valves already that I was going to use in my old house but never got round to)