Scalding/dangerous hot water from immersion heater

[ivrytwr3]

We moved into our new home yesterday (1999 build) and found there was no hot water. In the end we contacted the previous owners who informed us the heating is ran by the boiler (working fine) and the hot water is ran by the immersion heater which they left swotched constantly on.

We turned on the immersion heater (top part, as there is a top switch and bottom switch). A short time later we had hot water - yey!

However, at 2am, there was loud bubbling noises coming from the tank and the loft. I immediately turned off the immersion heater and found:

1. Pipe coming from top of immersion too hot to touch.

2. In loft the tank was bubbling like a boiling kettle and steam was coming from it.

3. When i turned on the hot water, it was scalding hot - no kidding, i couldn't touch it (you could have made a cup of tea with the water!)

I drained off some of the water through the taps and fortunatley we are all still alive this morning. I cannot find a thermostat anywhere, so can anyone advise what has happened? Do we need to get an engineer out?

(sorry for questions, but previous owner has not left any instruction manuals for system!)

Here are some pics of the system:

 

[TC.]

your cylinder is fitted with two immersion heaters, one at the bottom to heat up the cylinder at night when the leccy tarriff is cheap and the one at the top to provide hot water on demand, well kind of!

Do not under any circumstances turn the top one one not even for a nanosecond, it is dangerous and should not be used. It needs replacing before you can consider turning on the top part of cylinder. There is a problem with the termostat inside the top immersion heater, causing it to boil the water inside the cylinder and i bet its boiling out into your cold water storage tank. As it should.

Just in case i didnt mention it, get it replaced!!

 

[TC.]

if you go careful and ration your hot water usage, you can use the lower one to heat up your cylinder at night to provide hot water throughout the day, but when its gone it'll be a while before it gets hot again!

 

[doitmyself]

I am curious though, you must have a way to have hot water off the boiler; perhaps its gravity.

From the picture it looks as if it is a direct cylinder.

 

[TC.]

From the picture it looks as if it is a direct cylinder.

yup - the cylinder is directly heated by the immersion heaters!

 

[TC.]

i dont think from what i can see - the boiler has anything to do with HW supply. Im guessing that rather unusually the boiler is for the CH circuit only. Leaving the leccy immersion heaters to heat up the cylinder!

 

[ivrytwr3]

You're not the first to recommend this - ok, so looking at the set up i have, what would this cost and who would do it to link the hot water to the boiler?

 

[Billy Bob Bob]

you would need a different cylinder (indirect) a 3 port motorised valve,room stat,cyl stat but this would be a safer set up and cheaper to run

 

[TC.]

how old is ur boiler? and what make is it? me and boss ripped out a system like yours and fitted a combi boiler for 2k. was a giant system tho, and we were there for two days!

if you have the cash you would be better off investing in a combi boiler - the best on the market is a worcester bosch boiler! we have been getting them to 98.7% effecient!

though plumbstop are doing cheap boilers - glow worm i think, however these are B rated boilers and less efficient! stay away from Baxi!!

if you upgrade to combi - you HW pressure to the taps/bath will increase as it will be mains fed!

however if you really want to stay with your current set up - cant think why- other than cash issues, you would be better off going down to city plumbing, or screwfix, b&q and getting a replacement immersion heater, and paying a plumber to fit it, it should only take a hour max to fit and wire up. the options are entirely yours!

 

[TC.]

oh and just seen gasmans reply there is that option too!

 

[ivrytwr3]

anyone in Lincolnshire available - or any recommendations?!

 

[Rosebery]

Cylinder is already indirect by the looks of it.

 

[ivrytwr3]

ok, i've took the thermostats out and now have 2 x BT7 thermostats. On the net i have found these:

[DLMURL="http://www.theelectricalcompany.co.uk/search.php?xSearch=bt7"]The Electrical Company > The Electrical Company > Electrical supplies[/DLMURL]

Are these OK to use? Or can anyone recommend a better one?

Also, when i took them out, there were 2 wires going into the thermostats, 1 white, 1 grey. When replacing the thermostats does it matter what goes where? ie is it like a 3 pin plug, live, neutral etc?)

 

[GrahamM]

I would stop right there and get someone qualified to do the job.

 

[ivrytwr3]

lol, why? everyone is telling me how simple a job it is!

 

[TC.]

it may be a simple lookng job but if you screw it up you could end up causing alot of damage to either the building or a person through the spillage of scalding hot water.

you should get a plumber in to do this job.