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Hi I have just brought a house with and 30 year old electric hot water cylinder.
I have it set at 65deg and 70 comes out of the hot tape. After 5 mins its down to 40deg and after 10 mins 30deg. The pressure is good. Flow rate is approx 20 liters per minute from hot and I bit higher from the cold. I have replaced the element and the thermostat is working fine. Nothing states capacity of cylinder.
I have drained the cylinder and flashed out the best i can. This was after I ran the hot tap for a good 10 minutes, it still had plenty of water as it run at around 30deg out the drain for a least 10 minutes.
After a 5 min shower you have to keep turning the tap to hold a showering temp. After 5 mins the water is barely warm enough and the pressure is almost a lot lower as you twist the tap towards hot.
I have pictures http://sdrv.ms/16rwbyn (http://sdrv.ms/16rwbyn)
I need to understand hows this works. Why is this behaving this way? Does this sound right? Is my flow rate to high? Am i using all the capacity of the cylinder? Can this be fixed? Or is it a new one job?
Thanks a lot in advance.
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Can you please upload the pictures directly to the forum? As your link can expire in future and this thread can help others. Thank you.. It almost sounds like the ball valve might be rusty jamming and preventing the outer jacket to fill up with water. The outside jacket is what heats the water in the coil running on mains. Gotta love Hunson :)
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Hi is this what they call an elephant cylinder?
I gather that the low pressure water in the cylinder heats the mains pressure water in the coil. basically a heat exchanger.
I have seen systems like this but without the header tank on top, fed by a pressure reducing valve.
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Hi thanks for the posts.
I have uploaded as attachments.
The ball value is fine and the water is filling in the top tank.
So what you guys are saying is the water in the tank is heated with the element at low pressure. The coil at mains cold passes into the tank and is heated up as it passes though. So is this why the water is hot for a fews mins as this is the water waiting in the coil. So once this is used up the hot water is colder is there is minimal time for it to heat as i passers though the tank. Is this right?
If this is the case is there anything i can do to make this situation better? Should i bite the bullet and upgrade?
'Gotta love Hunson' What do you mean by this? are they good or bad?
Thanks for the help
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Yip this is an Elephant, boots what your saying above is correct. There are minor things you can do though to improve your hot water time. You mention that you get 70deg at the tap, you should really have a tempering valve (by law) in between and restrictors on your shower/tapware, this will reduce your flow and demand on the coil during usage allowing it to heat up much quicker. Hunson's don't operate that well on todays mains pressure and preform better on medium pressure. I would also check the thermostat to determine how accurate it is, at what temperature does it activate the element? There are several posts on this forum about elephants, use the search you might find more helpful info. Alternatively like you say a new mains pressure tank will do the trick :)
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Thanks Plumber, going to explore the many options for replacement as I want to renovate in a year or so.
Thanks a lot for the help, most likely be back once renovations start. thanks
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All the best! Look forward to hearing about your renovation :-\