immersion heater (please help/advise)

eilz

I have a very old boiler, and on at least two ocassions this week it made a loud noise for about 10 secs. I think i located it to be a green water PUMP next to the bolier. So I am guessing I will soon need a new water pump.

As we've had a little baby girl last week, I need to make sure we can at the very least, have hot water if the boiler decided to die. The big water tank in the bathroom has an immersion heater, which we have never used. So I connected it up, left it running for 1 hour, but the water did not get hot. So I removed the immersions element, but found it dry, so got me thinking. If the water level in my tank was too low, would the immersion heater struggle to heat the water? When I switch the immersion heater on, my electricity meter goes wild, so it must be doing something, just not heating the water. I have two water box type tanks located in the attic, should i be looking at these for answers? The last person up there was the man who did the insulation about 9 months ago.

At the moment the gas central heating seem to be working, but I wanted to make sure I had a backup, hence the use of the immersion heating, but I am now unsure how to check the water level is correct in the tank or not, as I am unsure as to what decides what the level should be in the water tank.

I would appreciate any help/ideas from all MSE'ers, thanks.

Eilz

maninthestreet

The tank with the immersion heater in the bathroom should be gravity fed from one of the tanks in the attic, I believe - is there a stop !!!! somewhere on the pipes from the attic to the tank in the bathroom that has been turned off?

Cardew

Your gas boiler should normally heat the same tank of water.(as you say it is very old I am assuming it is not a combi boiler). It is not normal to have 2 HW tanks.

The tank should fill up completely from the header tank in the attic.

If it hasn't been used for a long time they can get heavily scaled.

If it is a separate tank could there be a diverter valve?
This explains principle:

http://www.tehva.org.uk/downloads/DOM%209%20TEHVA.pdf

eilz

maninthestreet wrote: »

The tank with the immersion heater in the bathroom should be gravity fed from one of the tanks in the attic, I believe - is there a stop !!!! somewhere on the pipes from the attic to the tank in the bathroom that has been turned off?

The stop appears to be open ok, the weird thing is that, we do get hot water fine, using the Gas, but just not using the Immersion. I will check the tank(s) in the attic. Am I right in thinking that in the attic the smaller tank is for the radiators and the bigger tank is for filling up the water tank (header tank) in the bathroom?

Thanks for all the help.

eilz

Cardew wrote: »

Your gas boiler should normally heat the same tank of water.(as you say it is very old I am assuming it is not a combi boiler). It is not normal to have 2 HW tanks.

The tank should fill up completely from the header tank in the attic.

If it hasn't been used for a long time they can get heavily scaled.

If it is a separate tank could there be a diverter valve?
This explains principle:

http://www.tehva.org.uk/downloads/DOM%209%20TEHVA.pdf

The two tanks in the attic are both cold water I think, will re-check though. There is one smaller than the other, they look more like small square boxes not tanks, if that help.

thank again.

Canucklehead

Hi

I think you may have taken out the thermostat .Was it about 18" long and a little thicker than a pencil?

The hot water cylinder will always be full of water to the point of the first tee off the top , and you have water runing out of the taps so there is no doubt it's full.

A replacement immersion would seem to be needed.
The stat should be set at 60 degrees.

HTH and good luck.

Corgi Guy.

Cardew

Canucklehead wrote: »

Hi


A replacement immersion would seem to be needed.
Corgi Guy.

I am puzzled by the OP's statement that "When I switch the immersion heater on, my electricity meter goes wild, so it must be doing something, just not heating the water. "

Assuming he means that it drawing the 3 kW - where is the heat going in the hour it was switched on?

Anyway, you are the expert - and most helpful from all your other posts - so I will leave the mystery to you.

eilz

Canucklehead wrote: »

Hi

I think you may have taken out the thermostat .Was it about 18" long and a little thicker than a pencil?

The hot water cylinder will always be full of water to the point of the first tee off the top , and you have water runing out of the taps so there is no doubt it's full.

A replacement immersion would seem to be needed.
The stat should be set at 60 degrees.

HTH and good luck.

Corgi Guy.

Hi, yes I did also take out the thermostat, it was already set to 60 degrees, but I could not feel any water on the rod when taken out, if this rod was measuring the temperature of the water surely it shoukld be dipped in the water, but if I can't feel it wet, then replacing the theromostat and/or immersion heater wouldn't make much different right, or am I looking at the problem in the wrong context. I was gona find a long thin rod, to find out what the level of water in the tank was, if I found it too low can I top up the water in the tank, or should I be looking at the tank in the attic to do this.

Again, thanks for your help so far.

Canucklehead

Hi

Sorry I should have said that the thermostat is in a dry pocket and the heater is a totally separate item. Heat is transfered through the wall of the pocket. If all goes to plan a photo will appear on this post!

As previously said the cylinder is always full of water if not the element will burn out.
To remove the whole heater you will need an immersion heater spanner (as you can see from the pic. it's large)

In your OP you said that you 'connected the heater' do you mean that you wired it up? Or just switched it on?

You need to test for 230v at the heater and that the stat is working (it should click on/off by turning the temp setting slot) Use a meter that tells you voltage not an electrical neon screwdriver.

HTH

Corgi Guy.

eilz

Canucklehead wrote: »

Hi

Sorry I should have said that the thermostat is in a dry pocket and the heater is a totally separate item. Heat is transfered through the wall of the pocket. If all goes to plan a photo will appear on this post!

As previously said the cylinder is always full of water if not the element will burn out.
To remove the whole heater you will need an immersion heater spanner (as you can see from the pic. it's large)

In your OP you said that you 'connected the heater' do you mean that you wired it up? Or just switched it on?

You need to test for 230v at the heater and that the stat is working (it should click on/off by turning the temp setting slot) Use a meter that tells you voltage not an electrical neon screwdriver.

HTH

Corgi Guy.

ok, it makes more sense now, i removed the thermostat, having problems trying to open the whole thermostat, spayed wd40 still not budging, gonna retry again. I switched on the themostat, from switch and got smoke coming out, then I disconnect the themostat and connected the heater directly, and it did not smoke, and looking at the electric meter, when switched on it was running faster so assumed that the element was working ok, but never heated the water, so I think your right and I have a faulty immersion heater and possibly a faulty thermostat, so gona replace both. Do you have any where to buy both together?

Canucklehead

Hi

Have a read through this http://www.ultimatehandyman.co.uk/plumb_immersion_heater.htm
I prefer a flat spanner rather than the offset one shown as it has less inclination to slip off the nut. IMO the use of WD40 is a waste of time as it will not penetrate through the washer as it's so thick (maybe a week or two would do it!)
You seem to be a bit casual with the electrics, please take great care. A child needs both parents;)

Wickes will have both imm heater and the stat.Get the incaloy as it will last longer than the standard copper.

Good luck

Corgi Guy.