Disaster post bleed

[RichardHowells]

Hi all,

I have an open vent system. For a while we used the heating with the last two of the 6 radiators not working due to needing a bleed but the valves were knackered. As I was bleeding the two radiators by removing the entire hex valve, the expected air rush came but was not followed by any water. Once I had bled both radiators to the same effect, the heating stopped working.

I have checked the ballcock in the F&E isn't stuck, that the boiler fires fine, and the radiators are set correctly. The pump is a Grundfos Selectric 15/50 and when c/h is on it turns, and gets hot, and is fairly noisy. None of the heaters get remotely warm now, which is no fun this time of year. Any suggestions will be very welcome! Thanks in advance

Rich

 

[JohnD]

if you bled the radiators, and water did not squirt forcefully out of them, especially the highest ones in the house, but your feed and expansion tank has water in it, then you have a blockage.

This is most likely in the Feed and Expansion pipe (15mm) where it joins to the main circulating pipe (22mm) in a Tee, probably close to the hot water cylinder.

As you now have a blockage, it is too late just to use a cleaning chemical, you will have to cut out, clean and replace this blocked tee. Afterwards, you can then use Sentinel X400 or similar on refilling, once the water is circulating properly, and it will loosen remaining sediment so you can drain and rinse it out.

p.s. if the pump is noticeably hotter than the pipes feeding it, it is not pumping water. It is either jammed, or dry. Turn it off. Take out the large silver screw in the middle, see if water drip out, see if the spindle inside can be turned with a screwdriver.

 

[RichardHowells]

Hi JohnD,

Thanks for the extremely prompt response. So is it likely to be a blockage even though the heating worked on the other 4 radiators fine, and they would bleed ok, until i bled the last two? Could bleeding the last two have caused said blockage?

Rich

 

[dextrous]

As JohnD has said, probably a blockage.

Before cutting into any pipe, you may be able to shift enough of the blockage by attaching a hose to the drainoff valve and to a mains tap and forcing water backwards and up through the overfow if it won't stain the exterior brickwork too much. If your lucky, it may clear enough to enable the system to be flushed through subsequently from the header tank down by leaving the drainoff open whilst water works it way down. Then chemical etc etc as per faq.

 

[RichardHowells]

JohnD,

Just checked pipes around pump, and they are indeed noticeably colder. I removed the screw and no water came out, but I was able to turn the spindle. What does this mean for my predicament ? Thanks again for the help everyone.

Rich

 

[JohnD]

quite likely no water in pump. In which case don't run it until blockage cleared and system refilled as it will overheat, wear out, jam. More trouble and expense.

The bleeding did not cause the blockage, but it showed up the shortage of water (bleeding out the air allowed the water levels to equalise)i

 

[sturmey]

Just do what Dextrous said. You don't need to cut any pipes yet.

Attach a hose to an outside tap or any mains cold water pipe and the other end to a drain off or to a rad valve- you can use a 3/4" Hozelock fitting for this -it will fit onto 3/4" lockshield rad valves if you drain a radiator first.Then fill up and bleed as normal. This will usually clear the blockage and send it out into the f+e tank.

 

[RichardHowells]

Hi guys,

Thanks massively for all the help, its been top notch!

So today I got up post lie in to find the last rad in the bathroom leaking from the bleed valve. This obviously meant it now full of water, so I tested the pump again and that had water in it.

I ran the heating for ten minutes, and lo and behold, it now works fine! Is it likely I still have a small blockage somewhere that needs attending, or that I just didn't wait long enough for the system to be topped up the automatic filling?

Rich

 

[JohnD]

you probabably have a blockage which is not (yet) complete. however over time it will get worse, not better.

I strongly recommend using the X400 to wash away what you can. After 4 weeks drain it out and rinse a few times, this will remove most of the loose stuff. On final fill add a litre of X100 corrosion inhibitor.

Bale out all the mud from the F&E tank and sponge it clean to prevent additional sediment running down into the pipes.

If you can afford an extra £100 and do basic DIY plumbing, fit a Magnaclean as well.

 

[RichardHowells]

JohnD,

Thanks for the info, will be in town later so will look into the magnaclean as well. Unluckily for me I rent so will have to talk to the landlord before I start any real maintenance but I'm sure he'll be happy to have it done for him.

I didn't mention I live in Bath, Avon. Our water is notoriously hard, and absolutely packed full of limestone. Will the X400 cut the mustard against this or do I need to look into something stronger. I apologise for not researching myself more and instead relying on your info, but I'm short on time and you have been bang on the money so far.

Rich

 

[JohnD]

you can also get Sentinel X800 which, over time, breaks down old limescale deposits from the boiler. If it makes a lot of kettling or clonking noises, you might need 2 litres. Use it after you have done the cleaning and flushing as you fill it and leave it (you don't drain it out). It is mild and not acid.

you can also get aggressive acid cleaners which are quicker and stronger but as an amateur I am wary of these. One ate my jacket when it dripped out of a drain cock in the garage
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[RichardHowells]

Ok will get hold of some ASAP, thanks again for all the advice JohnD you have been a star!

Rich