Copper Cylinder Not Getting Hot - Should Pipes be hot?

[markymarkuk]

Hi
Here's a picture of my cylinder in airing cupboard. From previous posts you'll know I do not get any hot water, but radiators work fine. Its a Potterton system from the 70s, there are no options to turn on hot water/rads seperately, you only get hot water when the radiators are on!!

The picture shows the two pipes (A) that I believe should feed hot water to the indirect coil, and (B) takes it back to the boiler?
As the cylinder remains freezing cold even with the heating on overnight, I've been told the cylinder needs replacing. My question is, should the (A) pipe not even get warm or hot? because at the moment its stone cold???

The feeder tank is full but looks as though the waters been static in there for sometime?

any suggestions of what to check next?

//media.diynot.com/209000_208117_66208_76806473_thumb.jpg[img][/img]

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• markymarkuk
• 1 Dec 2013
• 2

 

[HERTS P&D]

Time for a new cylinder.

Andy

 

[markymarkuk]

you don't think its a blockage in the (A) pipe???

thanks

 

[HERTS P&D]

With a tank of that age, you have got your money's worth out of it.

Fit a new cylinder and have all the pipework checked- job done.

Andy

 

[denso13]

Check that the feed and expansion cistern in the loft is filling ok and hasn't emptied. Can you loosen the cylinder connections and check that the pipes have water in them?

 

[Nige F]

Check that the feed and expansion cistern in the loft is filling ok and hasn't emptied. Can you loosen the cylinder connections and check that the pipes have water in them?

- that cylinder is the best for gravity circuit on the primaries . It`s got an annulus heat exchanger - I`m not talking out of My anulus here Shame on you , Andy - I thought I was the king of totting here that old cylinder with some decent insulation - eg. an old eiderdown - will go on for years Those unions on the cyl.tappings will part easy - but you might not get much water out - possibly an airlock

 

[markymarkuk]

thanks for the help and suggestions. The feeder tank is full, but the water looks pretty still, as though its been there for ages!!!! Also, if I push the ball cock down no water comes in, maybe the value seized due to lack of use, but I'm guessing this has no bearing on the coil supply in cylinder?

 

[jackthom]

As denso13 says, crack open the top coil connection in the picture and check that water comes out.

It's perfectly possible the 15mm cold feed pipe is blocked and there's not enough water in the coil to keep the gravity system circulating.

 

[markymarkuk]

Thanks Ill try that, but as this thing is so old, won't that nut be as tight as...
And won't the water gush out if I undo it (knowing my luck it won't screw back on!!!!)

thanks

 

[Hugh Jaleak]

Worst case scenario, if you cant get the nut tightened back up quickly enough, you'll only lose the water in the system above that point, and if ballvalve is seized shut then it wont add any more. (Tie ballvalve up for additional safety if preferred!)

If you undo the nut slowly, easing the pipe gently away from the cylinder as the nut loosens (provided it'll move....), then any air should vent out followed by a dribble of water. Few old towels strategically placed should soak up worst of it. (Might be a bit mucky so watch carpets etc, it stains!)

 

[FiremanT]

Time for a new cylinder.

Andy

Maybe so, but ir doesn't answer the question. It is also hooked up to an old boiler, so it probably makes sense not to spend £00's without looking at the full picture.

OP. Get a magnet and offer it up to the Tee piece on the top connection. It should NOT attract, but you may find it does. Do this and let us know the result

 

[misterdubya]

OP, how much of a horizontal run of pipework goes from the boiler to the cylinder? On gravity as your is, the pipes may sag slightly and air can build up.

Its very uncommon, but if that's the case it can be cleared without un-doing joints. You just need to know how to do it. Cold feeds rarely block on gravity systems but as already posted, it needs checking after you've checked the F & E for water.

 

[markymarkuk]

OP I put a magnet on the pipes going in and out of the coil, the magnet sticks only to the lower pipe in the areas shown on the picture.
What does this mean, and how do I cure it? thank you

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• markymarkuk
• 1 Dec 2013
• 1

 

[Whitespirit66]

The Tee will be blocked. Drain down and cut the tee out. Check that the three pipes are free of debris from the cut ends. Solder new tee in and refill system.

If the header tank is full of stagnant muck that's been there years, bail this out and wipe out inside of tank before draining down. You don't want all the crud going down into your system when draining.

Don't forget to add corrosion inhibitor to the system before refilling to help prevent future blockages.

 

[hazetimesfive]

OP I put a magnet on the pipes going in and out of the coil, the magnet sticks only to the lower pipe in the areas shown on the picture.
What does this mean, and how do I cure it? thank you

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• markymarkuk
• 1 Dec 2013
• 1

you are the OP