Upstairs radiators won't heat up, not even at the bottom

[radiokid]

OK here are my details

Mexico Super 450FF Conventional floor standing boiler in kitchen (with pump located inside boiler housing)
Hot water tank located in bathroom directly above boiler
Two tanks in the loft, one smaller than the other.
Smaller tank has a ball cystern and an overflow pipe (wrapped in polystirine)
Larger tank has a ball cystern and is made of black plastic

Recently the upstairs radiators have stopped heating up fully, the lower part of the radiator has some heat but not much. I have tried bleeding these radiators, initially some air comes out, then it stops and there is no water or air.

The smaller of the two tanks in the loft (I guess this is the feed and expansion, or fill and return not sure to be honest) has a lot of brown sludge in it, which is quite disgusting. The water level is above the ball cystern, and to be honest it doesnt look like it has gone below the ball in quite some time. Also I have noticed that the overflow pipe that is routed outside has started to drip, where it never used to at all.

When the heating kicks in, all the radiators make a lot of sloshing water noises and the boiler also makes this sloshing sound (this goes away after a while, maybe 5 minutes or so).

The downstairs radiators seem fine. I had these balanced quite nicely, but now the upstairs radiators are not heating up, no amount of balancing seems to make a difference.

I tried to switch off all radiators in the house, with both the adjustable dial and the locksheild, and then turned the heating on. Wierdly the boiler would not fire up at all unless at least one of the radiators downstairs was opened up at both ends. No idea if this is related, but I thought it was a bit wierd.

Anyway, any help would be much appreciated.

 

[45yearsagasman]

If the small tank has water in it above the outlet at the bottom then you have a blocked cold feed.Trace the 15mm pipe from that tank to where it joins the system pipework and there is where it will be blocked.It needs to be cut out and cleared.

 

[radiokid]

Hi and thanks for the quick reply. Unfortunately we are currently renting and although I have let the landlord know, I was looking for something I could try in the meantime with the weather as cold as it is. Is there nothing that can be used to flush out the pipe?

When you say cold feed, is that an inlet or outlet? I am a bit confused about how our system works to be honest, although I am hoping to get some insight from this forum. Where does the outlet at the bottom go to, is this fed into the boiler in order to heat the radiators, or have I got that wrong.

 

[jackthom]

I have found with some older systems where the header tank is not much higher than the radiators, it sometimes helps to bleed the upstairs radiators only when the heating is turned OFF.

Otherwise there is a remote possibility of air being sucked in rather than pushed out.

 

[45yearsagasman]

If you are renting then I would suggest you should do nothing.Follow the 15mm outlet pipe from the header(small) tank to where it joins the system and there will be your cold feed connection.It will be in various places depending on system type.To unblock it will require cutting into the pipework.

 

[radiokid]

Ok,

So the posibility of this blocked pipe is the cause for my upstairs radiators only heating up at the very bottom? Or is the cause a combination of issues? Like I say, downstairs has no problem, apart from the extreme sloshing water noises coming from the boiler and radiators when the thermostat kicks the heating on.

 

[45yearsagasman]

The system is not filling with water hence no air being vented from rads when you try to bleed them and they are only warm at the bottom.

 

[radiokid]

Have done a bit more research. There are two pipes that I can see coming down from the feed and expansion tank. The pipes come down through the airing cupboard. One pipe has a red turnable valve, the pipe is quite narrow, this pipe runs down past the hot water cylinder and then splits off into two directions, One direction goes into the cylinder and the other part feeds into the first radiator on the top floor.

The other pipe is much wider, it goes down past the hot water cylinder, then has a T junction where it looks like it goes into the hot water cylinder. The other part of the T junction goes downstairs, and I presume into the boiler.

When the pump on the boiler kicks in, I can hear a lot of rushing water and some air coming from the large pipe. The large pipe is quite warm up to a point, and then becomes cold the further up it goes. The small diameter pipe is mostly cold, apart from where it is very near to the split at the base of the cylinder.

Just wondering if all this sounds normal, and what the pipes are that I'm looking at.

Incidently I think this means my system is a semi-gravity fed system.

 

[45yearsagasman]

Could you post a pic of the pipes?

 

[radiokid]

Hi and sorry for the late reply.

Our landlord sent a plumber round to fix the problem. But it is not fixed. The rushing sounds in the pipes and the banging in the boiler have been fixed, and now we have one radiator upstairs that gets warm (not hot), this is the rad nearest the hot water cylinder in the bathroom. But the rest of the rads are stone cold. And we are still freezing in bed! (not to mention our poor hamsters in the box room).

The plumber took the valve off the pipe in the third picture below (in the airing cupboard directly below the f & e tank in the loft). This pipe is the cold feed, and the larger pipe next to it is the vent pipe. But the size of the gunk in the f & e tank in the loft was a lot lot larger than could ever fit down that pipe. So I doubt cleaning the pipe at the point of its valve would have done anything to dissipate the build up of sludge in the f & e tank.

I've been up again in the loft and taken a pic of the f & e tank up there. It looks to be in the same state as before. That is, full of water above the ballcock. So I am not sure if the problem is fixed at all. I'll post a pic of the tank. Any thoughts?

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• radiokid
• 14 Dec 2010
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• radiokid
• 14 Dec 2010
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• radiokid
• 14 Dec 2010
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[radiokid]

Any advice anyone?

 

[radiokid]

Ok. So, I presumed the plumber had bled all the upstairs rads after he came to do whatever he did. But he had not, so yesterday (with the heating off) I bled them all. Every single one of the 4 rads upstairs were full of air! They took ages to bleed, but eventually I got water coming out. So, no more air in the upstairs rads.

Switched the heating back on, and they started to warm up, amazing! or so I thought. I figured I would let the system run for an hour or so, then check the rads again. So with heating back off I bled each one again, tiny bit of air, then lots of clear water, nice I thought. Switched heating back on, and nothing no warmth.

It has been like this since yesterday, heating came on this morning, but none of the upstairs rads got warm, not even at the bottom and not even the pipes going into the rads at the bottom.

After the heating had been off for a few hours yesterday evening, I went into the loft to check on the feed and expansion tank, and it seems fine. Water level is normal (just enough to float the float), so as I understand it, if the water level is going up and down as normal in the tank, the cold feed must be free of blockage.

Anyway, after another freezing night last night (and my calls to the landlord unanswered) I am at my wits end. What could the problem be now? Is there air still in the system somewhere that is preventing the hot water from the boiler downstairs from getting upstairs? Do I need to drain the whole system? I just don't know.

 

[D_Hailsham]

The water level seems rather high. Does the pic show the water level in the tank when the heating water is cold or when it is hot?

You need to check the level when the water is cold (brrr!). It should be just high enough so the valve opens before the water level drops to the outlet at the bottom of the tank. Bend the valve arm to adjust the level.

Do you have any motorized valves? If so, set them to MAN while you bleed the rads. This should be done while the system is OFF and water cold - start by doing downstairs rads first. Don't forget to bleed the pump - hold a rad underneath and remove large screw in the centre.

It would be sensible to bail out the tank and remove all the sludge etc when you are checking the level.

 

[radiokid]

Hi

Those pictures were taken when the system was hot. I have since looked when the system is cold, and the water level has fallen quite substantially, it is now about 6 inchs below the level in the pictures.

By motorised valves I take it you mean the TRV sort? We have just one of those on an upstairs radiator and it is set to MAX at the moment (fully open).

I have bled all rads last night, although I did start upstairs first, then downstairs. I was then alternating between the upstairs and downstairs to try and get every last bit of air out the system. All rads are completely air free. This morning I also bled the pump (large screw in middle) water came out immediately, so no air in there. I also noticed it was set to speed setting 3.

This is why I am stumped. All rads are full of water, as is the pump. F&E tank in loft seems to be going up when hot, and down when cold, as it should be. And yet still no warmth in upstairs rads.

 

[JohnD]

turn off all the downstairs rads and see if the upstairs ones heat up.

bleed all the rads when the system is turned off.