Persistant airlocking of some rads.

ScouseMouse

I have a recurring problem with my rads and need advice.

Over a period of a couple of months, some of my upstairs rads fill with air. I have bled them so many times, the nipple has rounded on some of them. I took one rad off, hammered a small socket onto the rounded nipple and took it out. I replaced it with a new nipple but now thats rounded as well.

I assume air is getting in somewhere or there is a leak. There is no signs around the house, i.e. damp patch so not sure what to do next.

The worst rad is in my box room, so have thought about replacing it with a rad that can be bled with a flat screwdriver. But first, filling it with some of the leak stopper in B&Q. When it circulates, it may solve my problem.

Anyone any ideas??

Thanks in advance.

aujopimur

If you have an open system you can check for a leak by tying up the ball valve for a day or so, if there is a noticable drop in the water level you have a leak.
Judging by your symptoms your heating system may be pitching i.e. hot water is being forced out thru' the expansion pipe into the expansion tank and fresh water is being drawn in, check for this by observation when heating is running.
Pitching can be overcome combining the cold feed & expansion,if unsure consult a plumber.

ScouseMouse

Hi, thanks for the quick reply.

There is no expansion tank in the attic. There is a safety valve at the bottom of the boiler which is piped out the kitchen wall. When triggered, it releases pressure outside, but this doesnt seem to be happening.

I have a valve in the hotpress with which I can top up the system as required after bleeding a rad. The boiler gauge normally stays around 1-1.5

The piping in this house is inside the partition walls, the original plumber ( who didnt want to know ) told me there is nothing underground. This is why I am puzzled. There are no signs of damp at the walls.

What do you think of my idea to get a new rad, fill with leak sealant, put it on and see how we get on?

demanufactured

take off one of your existing rads and try it , can do no harm.

JamesM

Make sure that the valve in the hot press is off and see how quickly the pressure goes down. That will tell you how bad the leak is. Do the rads "fill with air" (bad leak), or do you just get a little bit along the top. If you have drained the system recently, you will always get some air for a while.
If you use the correct size vent key, it should not wear.
Jim.

ScouseMouse

The rad in the box room fills with air in about a week I think. The rest just seem to get a bit around the top.

Again, as the box room one seems to be the most badly affected, If I change it for an easy bleed one, one that bleeds with a flat screwdriver, it would be just a case of bleeding that one every now and again to keep the system ok.

That combined with filling the new rad with leak stopper, it may cure it. Well thats how I see it.

Anyone else any ideas or anyone a plumber around dublin 24?

kmick

Had the same problem - the pressure in the system was too low. I had to locate the pressure valve and force more water into the system. I think from memory it had to be up around 2/2.5 bar. Mine was down below one. That would be system dependant so dont take that figure. It was just a case of opening a tap to allow more water in to pressurise the system. Its been working fine since. Took me ages to find the tap as it had been boxed off above the boiler.

Dilbert75

The important question is: "where's the water going?".... foundations of the house?

ScouseMouse

Topped up the system and closed the valves a bit downstairs and I have noticed a difference upstairs already.

The worst rad is now heating half way which is a big improvement.

House was warm and am delighted.