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Cheap way to increase hot water from heater?


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lamoe

Heater in Bohol, at highest  setting - is too small to really heat water (warm only at low flow) from main tank which is under eaves, never in sunlight - anywhere from 8 to 12 people there at any given time so main tank usually near ground water temps (50F / 10C?)

Don't trust house wiring to get larger heater (450W now) on 30 A breaker now.

There maybe 1 week a month - don't want to add additional holding tank and let ambient air temp heat it up - 3 weeks away and then 20 hours a day when there?

Concerned about bacteria growing while away :shocked: don't want to be adding chemicals or a recirculating pump.

Thinking of T-ing supply and discharge lines with simple by-pass valve and check valve in between.

One valve for recirculating some warmed water to be further heated

or

One for crossover (full open) and one restricted in supply close to T?

 

Thoughts?

One valve system possibly no cross flow because inlet line pressure (higher) prevents outlet water from recirculating or 2 (one to shut off crossover and other to restrict inlet flow)  and Bernoulli effect happens?

image.png.8f6617c98fd9bdeed88412e910e0a52e.png

 

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Woolf

450 w   water  heater    450  is NOT much

why 30 amp breaker ??  450 watt is only a little over 2 amps

a 4500 watt heather  is about 20 amps  should be good for your 30 amp breaker 

I have an AEG heater  works perfect     (when water pressure  is ok

temp  set at half  water too hot

https://www.lazada.com.ph/products/aeg-ax-35-single-point-water-heater-white-i161734154-s197837719.html?spm=a2o4l.searchlist.list.5.12811a9dzq5ObJ&search=1

Edited by Woolf
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hyaku

I have had my champs for 13 years now. Always on the lowest heat setting. The other two are far too hot.

I see it costs a bit more but I can recommend it. It's a 3.5 kw.  Just make sure you switch these thing off when the water is still flowing.

 

https://www.lazada.com.ph/products/champs-trimark-35-kw-singlepoint-water-heater-white-i113658561-s116817122.html?spm=a2o4l.searchlist.list.1.647b6e19IzlDmX&search=1

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lamoe
50 minutes ago, Woolf said:

450 w   water  heater    450  is NOT much

why 30 amp breaker ??  450 watt is only a little over 2 amps

a 4500 watt heather  is about 20 amps  should be good for your 30 amp breaker 

I have an AEG heater  works perfect     (when water pressure  is ok

temp  set at half  water too hot

https://www.lazada.com.ph/products/aeg-ax-35-single-point-water-heater-white-i161734154-s197837719.html?spm=a2o4l.searchlist.list.5.12811a9dzq5ObJ&search=1

fat fingered it's 4500 watts

Learned why WH is too small - if main tank in sun who knows?

Electric water heater coils themselves are are very efficient - the unit as a whole - depends - insulation, wiring, etc.

This site explains why 4,500 Kw @ 70% efficiency is not enough = cheapos like BIL bought - high end are 85% but$$$$$$

4,500 even at 80% = only 3,600 Kw

I used 70 F unheated water (combination of ground temp / air heating temp) - never measured - here in Winland, late afternoon 85 F outside  , no clouds for couple of days - water is maybe 80 - avg warm swimming pool temp - Bohol definitely much colder

105 F end temp - high for most people here - is avg in US

Some of his math terms are misstated and time to heat is suspect but not that far off
 

Quote

 

https://bloglocation.com/art/water-heating-calculator-for-time-energy-power

The calculators assume 100% efficiency and no loss of energy during the heating process.

Remember avg shower is 2.1 GPM

image.png.fb6addee2f428de6392dc7be49603b7f.png

 

image.png.4c396e0233f6aae59a9d304a4930e67a.png

image.png.61a0b60e3c66aec94e6e1fa93ea30bd9.png

Or this if want to do calculations

3.6 Kw x 3413 = 12,287

35 x 8.25 = 229

12,287 / 229 = only 52 gal / hr or .87 gal min

Quote

 

http://waterheatertimer.org/How-many-kilowatts-needed-to-heat-water.html

Formula for heating water inside tank:
Gallon Per Hour (Electric) = (KW x 3413) divided by (temp. rise x 8.25) or (KW x 414) divided by (temp rise.)
Let's say you have 5500 watt elements.
let's say incoming water temperature is 65°F and you want to heat tank to 105°, or 40° rise in temperature.

5500 watt or 5.5Kw elements x 3413 = 18771.5
40 degree temperature rise x 8.25 = 330
So in this specific situation, the element would heat 56.88 gallons per hour

If you have 4500 watt elements and incoming water temperature is 55°, and you want to heat to 120°, then the temperature rise is 65°
4.5 KW x 3413 = 15358.5
65 degree temperature rise x 8.25 = 536
So one element would heat 28 gallons per hour

 

 

 

Edited by lamoe
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Woolf

if  a 4500 watt heater can not heat the water either you have a flow like niagara falls or it is  chinese devalued watt 

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lamoe
1 hour ago, Woolf said:

if  a 4500 watt heater can not heat the water either you have a flow like niagara falls or it is  chinese devalued watt 

I didn't say it can't heat the water - gets very at at min flow to turn heater on

I take it you didn't bother to do the math?

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Woolf

you edited your post 29 min ago  my post was 1 hour ago  you want me to know in advance what you are going to add to your post  ???

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lamoe
4 minutes ago, Woolf said:

you edited your post 29 min ago  my post was 1 hour ago  you want me to know in advance what you are going to add to your post  ???

yep :rolleyes:

Apologize for not seeing post time - if it was my choice heater would have been min of 7,500 W but BIL said house wiring already installed couldn't handle it

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Paddy

@lamoe 3500W Panasonic. Water direct from well (holding tank is only used when there is a brownout). Plenty of hot water at 15-35psi and 3/4 on the dial. It needs about 1 minute or so to get going. 
7E311E65-106A-4669-A2BB-2269F2A6CD3D.jpeg.578a8d44e63a7bcaf7cfcb4902df3461.jpeg

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lamoe
2 hours ago, Paddy said:

@lamoe 3500W Panasonic. Water direct from well (holding tank is only used when there is a brownout). Plenty of hot water at 15-35psi and 3/4 on the dial. It needs about 1 minute or so to get going. 
7E311E65-106A-4669-A2BB-2269F2A6CD3D.jpeg.578a8d44e63a7bcaf7cfcb4902df3461.jpeg

What is the ground water temp and what do you increase it to? Temp diffrental

Tata uses full flow on ours

Confused by the 1 min delay  - mine is maybe 10 sec until as coils heat up.

 

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Paddy
7 hours ago, lamoe said:

What is the ground water temp and what do you increase it to? Temp diffrental

No idea. Too cold for a shower to just under too hot!

7 hours ago, lamoe said:

Tata uses full flow on ours

No restriction 

7 hours ago, lamoe said:

Confused by the 1 min delay  - mine is maybe 10 sec until as coils heat up.

This is the amount of time needed to get the flow to working temp at the shower head and then keep it at temp. It’s not instantaneous. 
 

Our heaters are plumbed in outside of the shower area. There’s an amount of water in the pipe between the shower and heater that will not get any heat at all. So there is a “warming up” time which is long enough for me to organize my towel and shave gear etc. 
That’s not designed...it’s just what it is. 

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lamoe
48 minutes ago, Paddy said:

No idea. Too cold for a shower to just under too hot!

No restriction 

This is the amount of time needed to get the flow to working temp at the shower head and then keep it at temp. It’s not instantaneous. 
 

Our heaters are plumbed in outside of the shower area. There’s an amount of water in the pipe between the shower and heater that will not get any heat at all. So there is a “warming up” time which is long enough for me to organize my towel and shave gear etc. 
That’s not designed...it’s just what it is. 

2 big variables that can affect temp

incoming water temp and flow

10 deg hotter inlet or cooler outlet and 1.5 GPM  could be almost a 70% reduction in needed Watts

What for me is low flow (not min to turn on - too hot over - 120f?) it's comfy - going back this week  - will fiddle with it - increasing inlet temp is simplest.

May just get a better brand of heater :idontknow:

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Paddy
1 hour ago, lamoe said:

May just get a better brand of heater

We’ve been through several “unknown” brands - but that’s more likely because MASELCO has a habit of giving us weird overvoltages from time to time. We didn’t specifically choose Panasonic this time. That’s because here you tend to take what’s available. When working, all the different heaters have produced hot water. 
Mind you, my partner tends to set the temp dial in the low area for heating. That doesn’t work for me. I turn it up - but I don’t have to turn it to Max. 

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lamoe
6 minutes ago, Paddy said:

We’ve been through several “unknown” brands - but that’s more likely because MASELCO has a habit of giving us weird overvoltages from time to time. We didn’t specifically choose Panasonic this time. That’s because here you tend to take what’s available. When working, all the different heaters have produced hot water. 
Mind you, my partner tends to set the temp dial in the low area for heating. That doesn’t work for me. I turn it up - but I don’t have to turn it to Max. 

Same here but I dial down flow - she's too short to move temp dial easily

3/4 dial - flow until it just turns on - cloudy / rainy days - little more sunny ones

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