Not enough hot water

rospaw · Jan 3, 2018

Bought my mother (87) a walk-in Jacuzzi tub. Ripped out the tub shower combo, plumbed, wired, rocked, built the knee wall to fill in the space ect. The guest house has it's own elec 40gal water heater that is 2 years old. It will fill the tub about 3/4 then runs out of hot water. Has to be full to run the Jacuzzi jets or it looks like a water park spray fountain when you turn the jets on. Don't asked how i know this. facepalm:

Can i turn up the elec water heater or is it a set temp?
How about adding a tankless in line to work with the tanked heater?
Or replace the tanked water heater for a tankless to run the whole house? (kitchen and bath)
Guest house has it's own service with a 150amp panel that is about 5 feet from the water heater.

StriperrHunterr · Jan 3, 2018

I believe even electrics have thermostats on them.

Do you know the condition of her water? 2 years seems to be a bit too quick but could the tank be sedimented?

rjcruiser · Jan 3, 2018

I'd guess that you're temp setting on the hot water heater isn't high enough which causes you to drain the entire tank trying to fill the tub at the desired temp.

50 gallon tub? Have to have it all the way hot to get the desired temp water in the tub?

hoytman308 · Jan 3, 2018

It sounds like your water heater doesn't store enough hot water to fill the tub all the way up. I would suggest either adding another water heater in line so that you have more hot water stored to use or going with a tankless type. It's not the settings and doesn't sound like a bad heater.

WayneB · Jan 3, 2018

there IS a thermostat, pop off the lower cover where the element is, you should see it. Set for about 160F, or if you think she won't scald herself, even higher.
Did the tub come equipped with an in-line heater plumbed into the circulation system? Check to ensure wiring is correct, and also ensure it is on a timer or separate switch from pump, or risk burning the element out.

I have a big Jacuzzi garden tub, I added a second lower volume pump to circulate water through the inline heater, with the water below the jets.. just to avoid the water park issue you've already discovered.

1gr8bldr · Jan 3, 2018

An example, A 50 gallon tank will not put out 50 gallon of hot water. Reason being that as the hot water is leaving the tank, cold water replaces it. Diluting the remaining hot water. You could expect 35 gallons before it starts to get luke warm.

rospaw · Jan 3, 2018

I think i can address all questions / comments

She likes hot water either bathing or washing dishes. Always has always will.
I will look again this time closer at the heater to see if it has a temp setting.
Tub size.... Big in my opinion. Will look at the paperwork for gallon size. It is a "chair" style tub. About 4' 6" tall 3' wide and about 5' long.
Tub has heated seat but not a water heater. If i had known it was a issue i would have wired in a inline in the "filler wall" i built. Now that i have finished the sheetrock/painted/trimmed/wire runs/plumbing run... i HATE to pull most of it all apart. I did put in a 12x16" access panel but no way to install one in that small of an area.
Water heater condition: No i do not know the condition of the heater other than 2 years old.

rospaw · Jan 3, 2018

Took both water heater covers off and found a temp adjustment. Bottom was set on 110 and top was 130. I set bottom at 130 and top at 150. Sound right? 150 is the highest setting on either top or bottom.

Jim Baker · Jan 3, 2018

rospaw said:
Took both water heater covers off and found a temp adjustment. Bottom was set on 110 and top was 130. I set bottom at 130 and top at 150. Sound right? 150 is the highest setting on either top or bottom.

Not a good idea to run 140 degree water in a tub or shower especially with elderly users. I know you are going to mix it but things happen.

Your probably still going to run out of hot water with a 40 gal HWH and 50+ gallon tub.

WayneB · Jan 3, 2018

you may want to look up a water heater booster, basically a tankless heater downstream of your tank water heater.

In my experience with tankless, NG or propane is efficient while electric are power hungry beasts.
Do your research of power requirements before committing dollars and labor.

GA native · Jan 3, 2018

Great builder summed it up well.

A tankless heater will certainly solve the problem. It was the only way my wife could use the garden tub in our last house. The gas ones I installed average $3000 for the complete install.

You could install a second 50 gallon heater in tandem with the first one for less than a $1000.

StriperrHunterr · Jan 4, 2018

rospaw said:
Took both water heater covers off and found a temp adjustment. Bottom was set on 110 and top was 130. I set bottom at 130 and top at 150. Sound right? 150 is the highest setting on either top or bottom.

I'd be cautious of maxing out the thermostat due to scalding concerns as has been mentioned above.

rjcruiser · Jan 4, 2018

StripeRR HunteRR said:
I'd be cautious of maxing out the thermostat due to scalding concerns as has been mentioned above.

Most newer tub/shower valves have an anti-scald feature that won't let you turn it all the way hot.

And in this case, it is probably the only way to get enough warm water in the tub without installing extra things.

Lukikus2 · Jan 7, 2018

StripeRR HunteRR said:
I'd be cautious of maxing out the thermostat due to scalding concerns as has been mentioned above.

And if you have cpvc or poly piping in your house, it's going to blow apart, elements and t-stats are going to fry and it lessens the life of the heater.

rospaw · Jan 7, 2018

Lukikus2 said:
And if you have cpvc or poly piping in your house, it's going to blow apart, elements and t-stats are going to fry and it lessens the life of the heater.

Newer custom built house with copper.

Tub will get just above 3/4 full of Moms water temp with the heater turned up.

So, should i put a tankless inline after the water heater?
Replace the tanked with a tankless? If so what size? (1 bath /full kitchen with dishwasher)
Put a larger tanked heater? (not leaning this way unless you can tell me why i should)

System is Electric and i will install myself. Power run will be up one side of a closet to the other side of the closet about 14' total. (water heater in same closet as panel, inside the house)
Panel/drop has 100 amp left after tanked heater removed. Number 6 copper enough? Have a 20' piece leftover from my outbuilding.

NE GA Pappy · Jan 7, 2018

#6 is only rated 65 amp

#3 is 100amp

rospaw · Jan 7, 2018

NE GA Pappy said:
#6 is only rated 65 amp

#3 is 100amp

100 amp is what is available in the panel. The heaters that i looked at for this size seem to be in the 40-60 amp range. Hoping someone will chime in on a similar type of 1 bath/ kitchen, electric tankless heater size.

Brands???
2,2.5,3, ect GPM???

NE GA Pappy · Jan 7, 2018

then you will need to replace the breaker with one the correct size. Code says the wire has to be able to carry the rated load of the breaker

Lukikus2 · Jan 8, 2018

There is good tankless electric heaters. Normally they require a double 30 amp breaker so you are fine on electric.

Not enough hot water

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