Alternatives to a powerflush? Advice needed.

[Sara100]

I have 6 radiators in a small 2 bed flat and a potterton suprima boiler and open tank system (I think...). It's an old system.

Since the winter my central heating has been playing up. It's been making gurgling sounds generally when the boiler is on, especially when the pump pushes hot water round, you can hear a trickling sound from one radiator, and a couple of times I've heard banging. A month ago one of my radiators started leaking (from a hole in the radiator) in my bedroom, which I got replaced.

Since then all the radiators won't heat up as fast as normal. There are two radiators specifically that are causing problems. A tall 'designer' radiator near the boiler, which needs constant bleeding and I can hear this trickling sound when the heating is on. Although I did manage to get it to bleed to the top when I shut off all the other radiators. When I did manage to do this, the water was not clear, it was very pale brown. But when the whole system is open, it needs constant bleeding and I can take the bleed valve off and nothing happens - sometimes a bit of air but then it stops, no water. It only gets hot in the very bottom (about a sixth of the radiator's length), not the top. The other radiator near this tall one in the spare bedroom also needs a lot of bleeding, but not as much, water comes out almost immediately and it stays hot all over. Again the water is a very pale brown. All of the water from every other radiator is clear.

I have tried bleeding all the radiators continuously to no avail. I have also tried shutting off all the other radiators apart from the ones I am having problems with one at a time to try and force the problem out as I thought it might have been air. I have also bled the pump. I tried balancing the system too.

I had a plumber round yesterday and they said that (amongst many things) that my gate valve needs replacing (it's 15mm rather than 22mm) and that the system needs a power flush as there's sludge/sediments. Does this sound right? He's quoted £350. I can't really afford that right now though but I'm thinking that if another radiator might leak because of this then I should do it. I also want to upgrade the system over the next couple of years or move, so I'm not sure whether it's worth it. But then I don't want to end up having to replace the system sooner just because I didn't get a power flush.

Advice would be appreciated on whether there is anything else I can do to solve the problems I'm having, if I need a power flush or there's something else a heating engineer/plumber can do, and if there isn't whether this is a good price for a power flush.

Many thanks.

 

[oldbuffer]

It is of course impossible to be definite without seeing your system, but I would be looking for a blockage in the pipe which connects the small feed and expansion tank into your system. If you have access to the tanks and pipework, and a magnet (even a fridge magnet) see if there is attraction of the magnet to the copper or plastic pipework from just after the tank to where it joins the rest of the pipework. There should be no attraction, but if there is it suggests the pipe is blocked with magnetite. The only real cure is to have that section of pipe cut out and replaced.

Assuming your system has worked satisfactorily in the past, I'd suggest that changing valves, unless they are otherwise faulty, is a "nice to have" rather than really important.

 

[75pete]

Well Sara, you can shut off and remove each rad and wash out with a garden hose. Clean out the header tank, fit automatic vents to each rad, having first s/w off the power supply to the boiler and drained down the water from the system. Or you could just shut off one rad at a time and remove it, flush it, fit auto vents ,replace then move onto the next (again best you s/w off the boiler) clean the header tank as best you can. Refill the system and add Inhibiter. Then look for other bleed points and vent and vent the pump. Check the rads for leaks. You should replace any washers that make up part of the connections at the rad valves, easy got from a plumbers or diy store as is the Inhibiter and auto vents.
Hope this helps.
Should have added: have a look at FQAs boiler and CH, 7,9,12

 

[Agile]

There is a serious fault with your system. Have you checked that it is not pumping over?

I am not sure that just a power flush alone will solve your problem as it sounds quite dire. It is quite likely that the feed pipe is blocked. I would usually charge about £165 to fix that. It is possible that if that is the fault and was cured then a power flush may not be essential with appropriate chemical treatment.

You say that you cannot really afford the perfectly reasonable £350. But not solving your problem risks other rads pin holing and replacing them will be a lot more. It is quite likely your problem has occurred because you have not had it properly serviced and the water treated with inhibitor.

Seems you think that a homeowner can just bleed a few radiators and solve any problems. In the real world a heating engineer is often required both to diagnose faults and carry out the required procedures to effect a cure.

Tony Glazier