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floating dutchman

expansion rate of water?

21 posts in this topic

So, I've go an older house with a header tank type hot water cylinder. Power company can turn off the supply to the cylinder during peak power usage times, standard set-up for older houses in NZ.

 

An hour ago I had a shower and the water was quite cold, after the shower I check the meter box and the cylinder is heating. We've had some bitterly cold weather here so the cylinder's probably been turned off by the power company hence the coldish shower.

 

Now the header tank is overflowing. I've had a beer to many to go climbing into the roof space to check it but it is possible that the ball cock is not turning off properly.

 

I wander if it is possible that the cold water (coming in from the street at about 7 deg C (guess)) being heated to 60 or 65 deg C is expanding and pushing back up to the header tank and making it over flow?

 

How much does water expand when you heat it 50 or so deg C?

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It's probably something else like the valve, the density doesn't change that much, Doesn't it slightly decrease anyway?

 

WIP4.gif

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Come on mike, If I wanted to sit down with a calculator I would have googled it, You can do better than that. :(

 

The hot water cylinder is about 4 ft high, the header tank is about 18" high, maybe two feet I can't remember. Both cylinders are about the same diameter. (I think).

 

How much could the water rise given the temperature change?

 

And now, the water has stopped over flowing leading me to think expansion, or maybe the bourbon I've switched to and the desire to not rebuild the header tank ball-cock again (must have done that like, six years ago?)

 

:)

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Come on mike, If I wanted to sit down with a calculator I would have googled it, You can do better than that. :(

 

The hot water cylinder is about 4 ft high, the header tank is about 18" high, maybe two feet I can't remember. Both cylinders are about the same diameter. (I think).

 

How much could the water rise given the temperature change?

 

And now, the water has stopped over flowing leading me to think expansion, or maybe the bourbon I've switched to and the desire to not rebuild the header tank ball-cock again (must have done that like, six years ago?)

 

:)

That's the point, I think it might not rise. The tank presumably expands with increased temperature, and the mass density of the water barely changes.

 

As long as it didn't freeze or boil, t's probably a valve.

 

Unless, maybe some water froze in your tank and then melted when the power came up ... but that didn't happen did it?

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Any air in the pipe/tank? That would push any liquid ahead in the pipe if the temps swung a fair bit.

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The tank would expand faster/more than the water. As Mike said, water density does not change much at all with increases in temperature, until the freezing or boiling point. I'm not sure that I understand your exact arrangement but within the range of water (0-100C) it remains very stable. Either extreme would cause a great deal of expansion.

 

The culprit is most likely a leaky valve. You may have a stuck float or something similar.

 

Along those lines, gasoline and diesel fuel do expand a good deal with temp change. I was responsible for fuel tanks at a mill some time back. We had several tanks, the smallest of which was 5Kgal. At post hurricane prices/availability there was a lot of pressure to make sure the measurements were very close. I took measurements (stick) in the early mornings to avoid the heat in the late afternoon. One morning I was tied up and had to stick the tanks later in the day. I then had to explain to a mill manager how we had managed to produce gas without buying any. Silly mill managers --

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Water is a strange material...it expands when chilled to freezing & when frozen. Most types of compounds contract when temp drops.

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So, I've go an older house with a header tank type hot water cylinder. Power company can turn off the supply to the cylinder during peak power usage times, standard set-up for older houses in NZ.

Have you checked the go heads? Some people wear them out at a rate of more than one pair per month.

 

The thermal expansion of water over this range of temp. is for all practical purposes Zero as others have mentioned.

 

Also you are on the wrong side of the Earth, is it possible that water behaves differently there :)

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possible? It DOES act differently....just watch it going down the drain in the wrong direction FFS!

 

Something very fishy about those that choose to live their lives upside down!

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Water is a strange material...it expands when chilled to freezing & when frozen. Most types of compounds contract when temp drops.

 

 

Just to be even more exact, water is its densest at 3.98 deg C (39.16 F). At any other temperature, the density of water is less than unity.

 

For example, if you cool water from 3.98 deg C to 0 deg C, it will expand. The densities (g/ml) are 1.0000 and 0.99987 respectively.

 

Ref: Handbook of Chemistry and Physics, CRC Press, 65th Edition (yeah, I'm old)

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O.K. so according to Mike's graph it's a two percent change, that's 3.6 Litre, on the outside. Nope, that's not going to make it overflow.

 

bugger, Oh well, at least I know that there's a couple of spare washers in a plastic bag hanging from a nail just above the header tank, from last time.

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Most hot water heaters have an expansion tank mounted above them. Or at least a line to relieve overflow.

 

Possible that if you have an expansion tank, it may be buggered and a new one is in order.

 

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The header tank is the expansion tank, This is a sixties house with sixties technology. Not that that is bad, hey it's still working and working well, It just needs some very basic maintenance and maybe a 63 cent part that I already have.

Anyway, its stopped overflowing so no trip in the roof space for me just yet. I'm guessing that a bit of crap from the water supply got caught under the washer and the next shower flushed it out.

Had a lot of rain here lately and even though the town water is filtered you can still get a bit of crap in the water.

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I haven't seen anyone mention the effect of gravity on the tank - since NZ is in the area of the South Pacific it will be influenced by spacific gravity.

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I haven't seen anyone mention the effect of gravity on the tank - since NZ is in the area of the South Pacific it will be influenced by spacific gravity.

Plus you have the Coriolanus effect. Water drains counterclockwise in those parts. The tank was designed for the northern hemisphere.

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I haven't seen anyone mention the effect of gravity on the tank - since NZ is in the area of the South Pacific it will be influenced by spacific gravity.

Plus you have the Coriolanus effect. Water drains counterclockwise in those parts. The tank was designed for the northern hemisphere.

 

Coriolis.

 

Coriolanus is a play by Shakespeare, and as far as I know he never went to New Zealand. If he did, he didn't write about it.

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I haven't seen anyone mention the effect of gravity on the tank - since NZ is in the area of the South Pacific it will be influenced by spacific gravity.

Plus you have the Coriolanus effect. Water drains counterclockwise in those parts. The tank was designed for the northern hemisphere.

Coriolis.

 

Coriolanus is a play by Shakespeare, and as far as I know he never went to New Zealand. If he did, he didn't write about it.

n. Coriolanus - when you try to flush the dreadnaught you just deposited without getting up from the seat, and the rotational inertia from the water tries to reauger the thing back up into your bomb bay. "Sorry for being late your Majesty, I just knicked off to the shithouse, and the turtle head went full Coriolanus on me." - From the novel Me, Your Holiness and A Bag of Crisps.

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Come on mike, If I wanted to sit down with a calculator I would have googled it, You can do better than that. :(

 

The hot water cylinder is about 4 ft high, the header tank is about 18" high, maybe two feet I can't remember. Both cylinders are about the same diameter. (I think).

 

How much could the water rise given the temperature change?

 

And now, the water has stopped over flowing leading me to think expansion, or maybe the bourbon I've switched to and the desire to not rebuild the header tank ball-cock again (must have done that like, six years ago?)

 

:)

 

are you sure you're not working with a toilet ???

 

toilet.jpg

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Sounds like you're lucky the whole bloody lot's not floating down Tasman Bay given what it's been like there recently. Rather damp?

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Sounds like you're lucky the whole bloody lot's not floating down Tasman Bay given what it's been like there recently. Rather damp?

 

Like all the flooding that happens in Nelson, I saw that on the news too. Something to be said for buying a house that's not in a flood prone area, (ie look at the lay of the land before you buy) and having a 60's built house, that's not built on friggen ground level. Our house is at it's lowest point about 500mm above ground level. Our neighbours "modern" house.... well they should be able to move back in in a couple of weeks.

Funny thing, I saw how heavy it was raining when it flooded, could not be bothered cooking dinner so I piled my 7 yo so in the car and went to Richmond to buy take aways, If I had have been 1/4 of an hour later I would not have been able to get home! Stupid stupid!

You get complacent when you never have any issues in your own home.

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Ok, let's start with the basics. What kind of water? Metric? US? UK? Canadian? Next what version? The current is v3.12.1.4, build 7.

 

Lets us know soon so we can help in detail.

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