Immersion Heater boiling all day(New Member)

[comfortablynumb]

Hi Guys..I've just got home to hear a gurgling noise in the Central Heating pipes, went upstairs to the airing cupboard and the emersion heater/tank sounded like a kettle boiling. switched off the power, went upstairs into the loft and the feeder tank has boiling water in it.
I put a new Red Jacket on the emersion last week, would this have any impact.? No heat in the radiators.

 

[Goldspoon]

Basically the immersion heater is faulty - it can be very dangerous.

http://news.bbc.co.uk/1/hi/england/somerset/7179092.stm

Do not use it. Get a plumber to change it.

 

[comfortablynumb]

Thanks Goldspoon..thats it exactly..do you know why the radiators would not be working.? how much is a new thermostat ?

 

[Goldspoon]

Are there two tanks in the loft - a small and a large?

If so which one has hot water in it?

 

[JohnD]

when you say Emersion, do you mean an Immersion Heater like this (electrically powered)?

or do you mean a Hot Water Cylinder like this (yours may be copper-coloured with a red insulating jacket)?

How is the hot water heated? Electrically or by a gas boiler?

how hot is the water that comes out of the taps?

how old is your cylinder and heater?

If you bleed the radiators, does water squirt out forcefully and keep coming? Even from the highest one in the house?

 

[comfortablynumb]

Two..the one with the hot water is directly above the emersion tank, the cold water supply/tank is in the other end of the loft.
I have cooled the water in the small tank by letting a bit of cold into it and then turned the whole thing back on on and it appears to be switching off and on, which suggests the thermostat is working, the radiators have now heated up as normal. can you have an intermitent fault on a thermostat.?
I am a bit concerned about the little tank having been damaged by the hot water all day.!!

 

[comfortablynumb]

Hi John D
it's gas heated by a back boiler behind the front room fire. it's a least 25 years old only 2 radiators on the central heating, never had any inhibiter or the like..I've only just realized how little maintenance has been done over the years. Why do you think it has just started working again.?

 

[JohnD]

at that age it quite likely has a lot of sediment and may have a partial or complete blockage (there are lots of other problems it might or might not have)

this can lead to radiators going cold, or to hot water pumping over into the feed & expansion tank, and to gas collecting in the radiators.

if it has got a pump, and if water is now successfully circulating through the boiler, cylinder and radiators, you could start breaking up this sediment by going to a plumbers merchant or DIY store and buying a litre of Sentinel X400 cleaning chemical, it will cost you about £15

this is a very mild cleaner, non-acidic, that is most unlikely to cause any damage, it is the one I usually use (I am not a professional). You will know it is starting to work when the water goes jet black with old sediment that has been loosened and is washing round in the water. There are other more aggresive cleaners that work faster.

but first, try bleeding the radioators like I asked and see what you find. Also, go back into the loft and see if water is coming out of the Vent pipe that hangs over the small (feed and expansion) tank. Look and see if there is mud at the bottom of this tank, if so, bale it out and sponge it clean to avoid any more sediment going down.

Do you know where the drain cock is for your radiator system? You will probably need this to draw the chemical down from the tank.

It would be very useful if you can post some photos of the pipes, valves, pumps, wires around your hot water cylinder, and especially to know how many pipes go into the cylinder, where, and if it has anything printed on it.

 

[comfortablynumb]

Thanks John D
That sounds right to me, I felt the radiator the other day and thought that the Top was hotter than the Bottom, this is normally caused by sludge ( I think) The Pump on the Central Heating system is a Grundfos Selectric UPS 15-50 it works silently.

 

[JohnD]

bleeding radiators, drain cock, vent pipe?

 

[comfortablynumb]

No.. I can't see any of them..I will have a go at bleeding the radiators tomorrow..I think I can do that..how much water shall I let out.?

 

[JohnD]

you are bleeding then to see if water squirts out forcefully. If the pressure drops within a cupful of water, you will notice it.

If you can't find a drain cock, you can loosen a rad valve until water dribbles out. After draining you can fit a drain cock, or a rad valve with drain cock incorporated (these are very handy)

If you find an old drain cock you will probably find the rubber washer has perished and you will need to fit a new one after draining. You can take the screw-out plug to a plumbers merchant to find a washer that fits (they vary a lot).

 

[comfortablynumb]

Hi John D

I have emptied the feed tank and scooped out the gunk at the bottom added the Sentinel X400 and let the feed tank refill itself.
All seems to be working well 24hrs later. It says on the Sentinel bottle to leave for a few weeks in extreme cases (which this is) and then drain the radiators. how does the stuff get round the pipes.?
Thanks for your help (and patience)

 

[SuperMario80]

how does the stuff get round the pipes.?

Usually pumped round via the circulating pump you mentioned earlier.

 

[JohnD]

but to draw the mixture out of the tank and into the rads, you need to drain a bucket or two of water out of the rads. There is only a small amount of thermal expansion each day in and out of the tank otherwise, which is not an effective way to get the chemical down. Stir it up before draining in case it has settled..

if you think there is already chemical in the bucket you drain out, you can tip it back into the F&E to recycle it if you like. Typically there is about 100 litres of water in the boiler, pipes and rads, so your 1 litre of chemical will give a 1% mixture, which is fine.

Tie up the ball balve in the F&E tank before draining. Have a look at the colour of the water you drain out today, and see what it is like in 4 weeks when you drain it again. All being well it will soon be black with loosened sediment. If you dangle a magnet in the black water you will see it becoming coated in black iron oxide sludge (this is how a Magnaclean traps the black particles out of the water, but you also need to drain in 4 weeks to get out the non-magnetic material which is usually a small proportion of the muck.