Not using enough hot water !

[Martin1]

Hi can anyone help? We have an Aga cooker (gas) which provides cooking and hot water only. A separate combi boiler exists for the central heating. The cooker used to provide hot water for a lot of people but now for only two. We can also heat the water with an electric immersion switch. This was in place for during the summer months when the Aga was switched off it giving off too much heat in the kitchen. A separate gas hob dealt with cooking and the immersion switch for hot water.
There is a hot water tank very large which is fed by another tank in the loft which I presume feeds the cold water into the tank for heating. The water in this loft tank has become quite warm and I think the rise in temperature affected some of the seals hence a leak? I have been told that the problem is that not enough hot water is being drawn off now and that this loft tank is now acting as a radiator. Is this possible? Is it correct and if it is what remedy exists? As a layman I cannot see why "not using enough hat water' should be an issue. Any system I thought should be able to adjust for this!!!
Thanks

 

[Nige F]

yes , it`s correct for an Aga because they don`t have ON/OFF control like gas or elec...........is the hot water cylinder lagged or old with a jacket? if it`s left exposed ie jacket removed or even cut the foam lagging off the excess heat can escape .............that`s the joy of aga/rayburns

 

[Kes]

Hi,

It's not clear (to me) whether the heating of the cold water feed tank in the loft takes place when the Aga is on or when the immersion heater is on, or both. And how warm is warm?

The only way I can think of for the tank to get warm is for hot water to be expelled sporadically from the expansion pipe which loops over the top of the tank. This would be caused by the water in the h/w cylinder coming close to boiling point. Neither expelling nor boiling should occur, and can usually be heard as a quite violent rumbling.

I don't know whether you can control the heat from the Aga. If it's the immersion heater then it should have a thermostat which can be turned down, or replaced.

If you remove insulation from the h/w cylinder (only if the Aga is the culprit) then don't forget to replace it when you use the immersion heater. You can run off hot water as an alternative, but losening the insutation does give you some benefit in airing clothes.

On the other hand a moderately warm cold water tank will not harm anything, and will pre-heat the feed to the h/w cylinder. I am not fond of thowing heat/energy/money away!

Rgds.

 

[Softus]

There is a hot water tank very large which is fed by another tank in the loft which I presume feeds the cold water into the tank for heating. The water in this loft tank has become quite warm and I think the rise in temperature affected some of the seals hence a leak?

Assuming that you're talking about the cold storage cistern, I suppose it's possible that a leak could arise from the water inside getting too hot.

I have been told that the problem is that not enough hot water is being drawn off now and that this loft tank is now acting as a radiator.

At first sight this seems like nonsense.

Is this possible?

It isn't possible with a conventional cistern and copper cylinder, if it's plumbed correctly.

Is it correct and if it is what remedy exists?

I can think of two ways in which the water in the cistern is getting hot.

1. Failed or incorrectly set thermostat on the immersion heater, causing 'boiling over', whereby hot water emerges from the vent.

2. A faulty mixer valve, somewhere in the house, that's being fed from unbalanced supplies. In this case you would be getting another symptom, which is water escaping from the overflow warning pipe and dripping (or cascading) outside the house.

Please note the following:

On the other hand a moderately warm cold water tank will not harm anything, and will pre-heat the feed to the h/w cylinder.

Quite the opposite - if you store water at the wrong temperature is becomes hazardous because it can be a breeding ground for bacteria, and some quite nasty ones at that. This is why the Water Regulations stipulate that insulation is to be used to keep down the temperature of the incoming mains and the stored water.

 

[Martin1]

Hi,
Thanks to everyone for replies very helpful. Had to get a plumber in however , began to leak again !! He said what you are all saying : Thermostat for immersion heater was set to maximum and bust. He thought steam was coming into the cold water tank via the expansion tank/overflow and forcing rise in water. Also heat had broken seal at water overflow. But as mentioned by you I recently fitted a thermostatic mixer to a second shower so might have to wait and see. Now powering up system, have reset ballcock, fixed seal and waiting for result.

Again many thanks to all, some politicians might benefit from this mutual assistance!

 

[onceceltic]

I had exactly the same issue.

We have a rayburn that heats the hot water and is used for cooking but is turned off in the summer. We also have a combi boiler for CH and for hot water when the rayburn is off

I fitted a thermostatic mixer shower last november and it seamed to work fine for a few weeks then I noticed that there was water coming out of the overflow. Its hard to say how long this had been happening as the overflow feeds direct into some guttering, so it was only on a dry day I noticed that there was water still coming dow the downpipe.

so I went up the attic thinking it was the ball valve and got qite a suprise to find all the contence of the attic (boxes of Xmas decorations ect) all wet. The entire inside of the roof was covered in tiny drops of warter.

I then went over to the cold water tank and it was warm.

In a nut shell the presure from the cold water mains feed to the new shower was pushing the hot water in the cylinder back up to the cold tank.

I was able to purchase £8 a 22mm inline non return valve, which I fitted between the hot cylinder and the new shower.

Not had any problems since.

 

[Martin1]

Thanks for replies I am putting in the inline valve as suggested today! I am interested as to why this problem is occuring. When I have the mixer running I think I can understand why but what I can't understand is why the cold water tank continues to overflow when all taps are off. It doesn't just fill up after tap use it is a constant - confused.

Thanks

 

[Softus]

... I can't understand is why the cold water tank continues to overflow when all taps are off.

It's because you have a faulty valve that has been incorrectly installed.