Cold upstairs

[R0b1et]

Hi all,

Our upstairs (small 2 floor 2up-2down house) radiators only get hot on the bottom few inches, no heat at all above them, downstairs certainly appear to work fine and have no trouble maintaining a decent temperature in the bathroom and living room. But the issue means our bedroom and the nursery are really quite cold... and with a small baby, this is a bit of an issue.

Unfortunately, I know little about plumbing, but really can't afford a plumber unless there is no other option. But, what I do know:
-The house is 1920s, but the heating/hot water system must have been updated at some point from first installation as there are a few pipes that are blocked off in the airing cupboard... I'd suspect this may have been in the late 90's/early 2000s as that is the approximate age of the boiler (which is a odd make, but a good boiler for it's time [known from when we had a gas leak]). In the loft is the fairly normal 1 large tank (the ball cock got limescaled and caused a drip a while back [I managed to fix that]) and the small tank (I assume an expansion tank)... it looks like there's a fair amount of orange (rusty?) stuff at the bottom of that tank. Both tanks have water and functional ball cocks. Since I know from piping diagrams it might help, the tanks are in the loft, hot water cylinder in the airing cupboard upstairs and boiler on the ground floor. We definitely don't have a combi boiler before anyone asks.

I've tried bleeding the radiators with essentially no success: There was a hiss for quite a while (probably more than a minute though I didn't time it), but no water appeared... the radiator perhaps got warmer a small fraction higher afterwards, but further efforts have made no difference.

That made me suspect we had some form of blockage from the expansion tank, stopping water "topping up" the system when the radiators are bled.

BUT I have discovered in the airing cupboard (rather well hidden by the shelving unfortunately) a green tap/valve on a pipe, that I am wondering what does? It is on a thinner pipe than most in there that comes from the piping just below the pump and disappears up into the loft (in the direction of the tanks)... but it is proving hard to figure out which pipe is which once in the loft... they are lagged by time they emerge... all in identical lagging... so I can't figure out where the pipe goes.

So, I wonder, what does the green tap/valve do? Is this the problem, turning that tap will allow water down into the central heating system? If so, will it just require a temporary opening, to refill? or will it need opening and then the radiators bleeding? Should it be open or closed now/long term? I'm rather nervous to turn it currently since I don't know it's purpose and am afraid of flooding the house etc.

The images below show what is going on with the piping in that area, with red arrows showing the pipe with the green tap/valve heading for the loft.

Untitled

• R0b1et
• 13 Dec 2011
• 1

Untitled

• R0b1et
• 13 Dec 2011
• 1

Any help or advice would be really useful.

Thanks, Rob[/list]

 

[bathjobby]

Rads cold at bottom usually means sludge, rads cold at top usually means air so it sounded promising that you had air coming out of the rads, but bad that it wasn't followed by water, but, that also explains why they are not getting hot. So, why no water flow in upstairs rads.. Have you subsequently checked the water level in the F/E tank, did bleading the rads empty it ? Does the ballcock feeding it work i.e. if you press it down does water come out of it ? I personally wouldn't mess with valves that I didn't understand what they do. If you want to trace the pipes from the cupboard to the loft get a long piece of stiff wire (coat hanger) and push it up through the ceiling right alongside the pipes in question, then you can see which on it is in the loft. Let us know what you find from the above.

 

[R0b1et]

I should have mentioned those, bleeding had no apparent affect in the tank in the loft, but the ball cock does work when pushed (the water level looks sensible).

Sounds like you are as wary as I about turning the tap.

But if that pipe goes to the expansion tank, would it not be a refilling pipe, and the very purpose of said tap/valve be to refill (and hence remove the air)?

I guess the pipe basically can only go to the expansion tank, big tank (what's the proper name?), in either case as an overflow or under water level.

 

[JohnD]

if there is water in the F&E but it is not getting to the rads, and the upstairs ones are half empty, then most likely you have a sediment blockage in the Feed & Expansion pipe. This is very common in old open vented systems, especially if they have not been kept clean and treated with corrosion-inhibiting chemicals. As you now have a blockage, a chemical clean will not work as it cannot flow down the pipe.

Most likely it is at the bottom of the "U" shaped bit of pipework.

Get a magnet and hold it against the pipe. If the magnet sticks there is a black iron oxide blockage. If you are in a hard water area it will be a hard lump mixed with limescale.

If the part can be removed by undoing some compression joints, do that (after baling out the F&E tank, and putting a bucket under the joint). If not it will have to be cut out and replaced.

Afterwards, give it a chemical clean with Sentinel X400 which you can leave circulating for 4 weeks before draining it out with the loosened sediment. On final fill add X100 or similar corrosion inhibitor.

 

[R0b1et]

So definitely nothing to do with that tap then?
I was wondering if that tap was the (in effect) blockage.
I can't spot a U shaped bit of pipework - but am at work and can only use the pictures I have taken.

I guess I'm heading here to the question of if I need to get a plumber in to sort this, how much will it cost? Any ideas, even ball park?

 

[JohnD]

in your third picture, there is a 15mm pipe coming down (looks like the F&E pipe) looks like it is joing a 22mm or 28mm horizontal (looks like the main circulating pipe) which then goes upwards to a pump valve. That's the "U" I meant.

BTW to the right of the 15mm F&E it looks like the 22mm vent pipe, which should curl over the top of your F&E tank to take any overpressure (e.g. if the F&E pipe is blocked, like yours is). If you attach a hosepipe to the vent pipe, it will enable you to fill the system, and sometimes the pressure will force a soft blockage up and out through the F&E. In the event that this does work, you must do a drain and chemical clean quite quickly as there will be lumps of the blockage circulating through your pipes. Bale any dirt and sediment out of the F&E tank.

If the problem is what I think it is, the job shouldn't take a plumber more than half a day, most of the time will be in draining, refilling and mopping up. I am a householder not a pro. If you want to DIY, start by cutting that 15mm pipe and poking at the blockage with a bent coat-hanger, then take off the pump and poke from that side. Lumps of sediment may jam or damage the pump though, especially if the pump is sucking from the blockage area.

 

[R0b1et]

But that horizontal pipe is hot, and presumably flowing OK since downstairs heating works fine. So the blockage would have to be above that surely?

It sounds like you think the pipes do what I think they do, but why is there the tap/valve, could it not simply be that it is closed when it should be open (perhaps temporarily).

 

[JohnD]

then start with the 15mm vertical pipe. test it with your magnet to try to find a blockage. Or it might be blocked at the top with insulation, dirt or a drowned mouse.

The valve should normally be open, it is probably a service valve to be used when draining or repairing.

 

[R0b1et]

Thanks John, I'll have a go.

A friend I just mentioned the symptoms to wondered if it could be a balancing issue... he had a similar fault caused by balancing, but he hadn't tried bleeding radiators to know what that would do.

Does that sound a possible? I guess it would be easy to test... turn off downstairs radiators (counting the turns so they can be returned to the current state) and see if upstairs start to work.

 

[JohnD]

no.

the clue is "Our upstairs (small 2 floor 2up-2down house) radiators only get hot on the bottom few inches, no heat at all above them, downstairs certainly appear to work fine"

meaning there is no water in the tops of the rads even after you have tried to bleed them.

 

[R0b1et]

OK, thanks.

Definitely think I shouldn't try turning that green tap?

 

[JohnD]

if it's turned off, turn it on and see what happens. It should be on.

 

[R0b1et]

OK, thanks... at least I can feel like I'm doing something!

Its location makes it possible my wife could have accidently turned the tap while pushing towels etc into the airing cupboard.

Your advice is much appreciated.

 

[R0b1et]

I spent a while with a buddy identifying pipes... ie which go where. So at least I achieved something. The green tap is definitely on the down from the F&E tank... but the tank is really quite orange, so before I even think about moving the tap to see if it is open or closed, I'll syphon out the expansion tank (+ sludge [which isn't think, just lots of small particles so should go through the syphon no trouble]).

I also bailed enough water from it to confirm the ball cock is working fine.

So it is almost certainly the F&E pipe, with the vent pipe (as JohnD suggested being the one next to it). Given the financial constraints I have, but the desire for hot bedrooms, even if a temporary fix until we can afford a true fix - and not being very good at DIY. I'm wary of having to drain the system causing more trouble than we have as it is (the daytime spaces are fine).

BUT, except the different levels, the vent pipe and F&E pipe basically go to and from the same place... just the vent pipe goes over the tank so can't refill the system. You suggested I could pop a hose to the vent pipe to refill the system... that's certainly tempting to try that, but to be honest, I'd rather not shift the blockage for fear of the drain etc not going well... perhaps If I could manage a syphon down the vent pipe, with low gauge tube for minimal pressure I could top up the system, without the blockage taking any significant pressure?

Anyone got any thoughts on that "fix symptom, not cause" approach?

 

[R0b1et]

If refilling, would probably need to be bleeding the radiator (likely one at a time from simple man power) simulataneously I imagine.