Minimal hot water from 30 inch element.

[Benny_the_ball-valve]

I have recently installed a 30inch element into a 900 x 450 HW cylinder. Though the HW connection is below the bottom of the dome I would have expected this to be quite sufficient for providing enough hot water for showering. This, though, is not the case. The element gets hot and hot water is available for a short while but certainly not enough for a shower. I have tried to turn the temperature setting on the thermostat to almost maximum but now there is absolutely no hot water. Any ideas?

 

[Balderdash]

Thermostat faulty or too short.

 

[Benny_the_ball-valve]

I am a bit late getting back but thanks for the reply, Balderdash.

Looks like it's the latter. I have replaced the previous 11 inch thermostat with an 18 inch. This did give a bit more hot water but still insufficient so I have turned up the temp to 70 degrees celsius and set the timer for 4hrs in the morning and the same in the evening. I am unsure as to whether 70 degrees is too high but the range is calibrated to 85 degrees. Hope this does the trick.

 

[rssteve]

could it simply be that you are drainign the hot water in the tank too quickly, can you heat it up then feel if the water near the bottom of the cylinder is hot or not?

 

[glasgowgas]

I am unsure as to whether 70 degrees is too high but the range is calibrated to 85 degrees.

 

[glasgowgas]

sorry 70 degrees C is too high

 

[Benny_the_ball-valve]

could it simply be that you are drainign the hot water in the tank too quickly, can you heat it up then feel if the
water near the bottom of the cylinder is hot or not?

The next check I make (tomorrow) I will remove some of the polystyrene jacket and check the heat in the cylinder.

sorry 70 degrees C is too high

Well I will reset to 65 degrees and hope that the extra time for which the element heats the cylinder will provide for the required capacity.

Thanks, guys.

 

[Benny_the_ball-valve]

Not much improvement, sadly. I set the timer to come on for about three hours early this morning but was still deemed insufficient to provide a good shower. I shall now set the timer for two cycles of four hours to see whether this yields the required improvement.

If, though, this proves futile are there any other possibilities? For instance would installing a horizontal cylinder be a benefit? This would at least allow for a larger vessel to be installed.

 

[Fluffster]

How old is the cylinder? are you in a hard water area ?
If so the bottom of your tank could be scaled up.
Take the element off again and have a look with a torch at the bottom of the cylinder.

What was the problem with the previous elemet you replaced.
Pete

 

[rssteve]

leaving the cyliner on heat for longer will not heat more up as the stat will cut off the power once up to temp. What size is the cylinder? And approx what flow rate have you got coming out opf the shower, how long does it runf or before going cold.

 

[rssteve]

also is it a gravity shower or have you got it pumped, i bet if its pumped you just need a bigger cylinder.

 

[Benny_the_ball-valve]

Fluffster: The cylinder is new. Sorry, perhaps I should have made that clear. So it is the first element to go into a new cylinder. But we are in a hard water area – London.

Rssteve: The cylinder is 900 x 450 with a capacity of 120 litres. The flowrate I reckon is about 10 litres/minute (hot & cold mixed). It’s a gravity shower. The tenant tells me it lasts little longer then 10 minutes before the water goes cold.

 

[kevplumb]

thats about right depending on how hot the shower is

 

[Benny_the_ball-valve]

thats about right depending on how hot the shower is

That's what I am worried about. The cylinder is hot to within about 10cms of the CW inlet after the element has done its stuff. But this setup is expected to provide a shower for two women. Is it worthwhile fitting a larger cylinder? It would only be able to be installed horizontally. Would there any problems with this arrangement?

 

[Terrywookfit]

Get one with an element in the bottom.
The top will be 70 deg but below the stat willonly be pi$$ warm.
Thats how thermal stratification works.