Teenager showers draining the hot water tank

[Lobster]

This is half just a rant; half a serious query...

I now have three teenagers who have all graduated from the allergic-to-washing phase, and who now believe it's their unalienable right to stand in the shower under a stream of hot water gazing vacantly at the wall or doing whatever the hell else it is they do in there, until the hot water simply runs out. Can be >30 minutes, no problem.... Apart from the stupid energy bills, it means there's no water for the next person in (normally a parent) - and of course being teenagers, neither of those issues are problem in any way, so no matter how much I rant, threaten, and bang on the door, I just get a "whatever" or "hey chill out dad" and no modification to the behaviour.

We have a fairly large, unvented HW tank, which believe me heats up pretty quickly and should contain plenty for 4 or 5 showers.

I'm trying to think of a reasonable, creative way of solving this one and would welcome any ideas!

I know the obvious way would be to time them, then maybe introduce sanctions or something if they go over, however, one of the difficulties is that invariably I don't actually know when they go in the bathroom or come out.

I can't do something that will impact on other users, so nipping down the in-line service valve on the HW to reduce the flow to a trickle isn't really an option, any more than adding a timed meter is!

The only things I can think of is to install a stopcock to the HW somewhere accessible (maybe one of those remote ones?); however that only works if I know when they enter the shower (and they're quiet, the cunning little blighters); plus it would mean rousing myself from in front of the fire to go and switch it off. A non-interventional method is what's needed.

Thoughts please?!

David

[Bob Mannix]

Hate to say it but this is the situation where a combi boiler (unusually) knocks the opposition right out of the game - endless hot water and a powerful shower. Of course that only solves the inconvenience but it's much easier than standing outside shouting (I have done both). At least they are clean teenagers rather than grungy ones. All things pass.

[Rod]

Meter? You just need some means of recording shower usage. Even a padlock on the shower would do.

Establish a charge structure. Five minute shower once a day - free. Each extra minute up to 10 minutes - 10p. Each extra minute up to 20 minutes

- £1. And so on.

Any unpaid bills incur further sanctions such as 'no more showers'.

[Gordon Henderson]

Electric, coin-operated shwoer.

A brief google shows:

'll pay for itself in no-time :)

Gordon

[The Medway Handyman]

Simple. Set up a device that plays Max Bygraves records through a hidden speaker after 5 mins. Triggered by a timer on the shower.

But I ain't bovvered though...

[Adrian]

Lobster gurgled happily, sounding much like they were saying:

You're forgetting the most effective, most satisfying and most pleasurable - as well as cheapest - solution.

Beat 'em to the shower. Just. Have a long hot shower yourself. Share it with the missus. Then get out JUST before the hot water runs out.

There'll be a queue of teenagers at the bathroom door. The first will get in, and - a minute later - it'll go cold. If you time it right, it'll be just as the soap and shampoo are fully applied.

[Tim S]

Lobster coughed up some electrons that declared:

...

Electric valve, flow switch in the HW pipe to the shower and some sort of timer between them.

After the water starts flowing (and trips the flow switch), sets a run down timer that resets a) 10 minutes later or b) When you press a secret button hidden somewhere.

[Exiddor]

Install a key-operated lock and only give keys to the parents. They won't stay in there long if they know that someone can walk in on them at any time. :-)

[Andrew Gabriel]

ISTM that you simply want a smaller hot water cylinder, so it runs out after ~10 minutes of shower. It will likely have heated up again by the time next person goes in there. You can easily reduce the effective size of a hot water cylinder just by moving the thermostat higher up the side, which is a temporary change you can easily make until they leave home.

[Dave Plowman (News)]

Flow sensor followed by a motorised valve on the hot water feed with a one shot timer? So it closes after *your* preset time. Say 10 minutes. How the timer resets is up to you - after a preset time or via a control outside the bathroom.

[Tim Downie]

Now that's smart! Wish I had thought of that.

Tim

[Doctor Drivel]

As been said a high flow combi is what you need. To get over the problem is not going to be cheap.

1. You could replace the existing boiler with a high flow combi and do away with the unvented cylinder.
2. You could fit a high flow Rinnai multi-point (they have outdoor mounted models), and keep the boiler as CH only. Have a flow switch on the cold feed to the Rinnai to switch out the boiler when DHW is called. This keeps your gas consumption within a U6 meter.

Similar to the Twinflow:

are very well made. Andrews make similar models.

1. You could heat the unvented cylinder with a plate heat exchanger and bronze pump (using available tappings and/or Surrey flanges). This puts the heat from the boiler at the top of the cylinder and it acts like a combi with the cylinder as a large buffer. Heat up time beats the internal coil. If you have condensing boiler, have the flow into the plate heat X, out of the plate and into the top of the coil, out of the coil returning to the boiler.

How big is your boiler in kW and what type? Condensing?

I would be inclined to go for No. 3 as it is the cheapest and most efficient, with an amazing re-heat, and acts as a combi when needed to (you will never run out of DHW, as wehn eh cylidner is exhausted it reverts to what the boiler gives) and saves gas too. The cost is a plate heat exchanger, £100-£150 (get a 100 to 130kW plate) and a Bronze pump - £50

And some pipe and fittings.

[The Natural Philosopher]

Timer switch *outside* the bathroom and a motorised valve?

Hit the switch: you have water for 5 minutes only.

[The Natural Philosopher]

endless warm water.

and a

And a pathetic shower, especially if you are washing the dishes.

[Doctor Drivel]

Not as smart as you think. The coil would have to be moved up as well, otherwise a slow reheat, so not the answer.

The best and cheapest is what I pointed in my other post, No. 3 the plate heat exchanger and bronze pump. Similar to this in operation:

can be retrofitted by using a Surrey flange on the top of the cylinder, and maybe on the cold feed at the bottom too.

In fact using a direct cylinder, a plate heat X and bronze pump, it is usually cheaper than the indirect coil cylinder version, and totally out performs the coil.

It in effect increase the cylinder size as the energy in the cylinder and the boiler are combined when the cylinder stat cuts in. It put hot water from the boiler at the top of the cylinder where it is needed.

[Doctor Drivel]

You clearly haven't a clue. High flow combis can do two to three showers simultaneously.

[gazz]

seems combi boilers and cfl's are the items that most divide this group,

dunno if it's just people who dont own them saying they are crap due to jealousy or something, or they have tried a really cheap crappy version in the past and were rightly disappointed, and now think everyone is using the same cheapo crappy thing they did.

[kinslerp]

A really stingy low-flow shower head, like you get in student halls. The hot water will last longer, but they wont want to stay in such a feeble shower for longer than it takes to wash.

#Paul

[Doctor Drivel]

You are right. Most here are DIYers and don't know what is on the market. Combis have changed dramatically in the past 8 years or so. They buy cheapo

24kW 10 litres/min scrap and then judge all combis by that. What amazes me is that they rigidly stick to this ridiculous belief.

Even so, a 10 litres/min combi will deliver 300 litres in 30 minutes. Exhaust a 300 litre cylinder and it takes an hour to heat up. A combi goes for ever.

An Ethos 54C will deliver approx 23 litres/min, which is 690 litres in 30 minutes. Ever seen the size of a 700 litre cylinder and how much the cost?

A combi must the first choice in the average British home.

[Doctor Drivel]

And the Dad has to put up with the same shower too. Not good.