Installing a Water Heater Timer

We have recently had a solar PV system installed.
That has made me very conscious of our usage.
I have been tracking our usage and production since the installation.

Add to that the fact that my hearing and memory seem to be taking a hit due to age.
I have left the hot water running over night because I forgot I had turned it on and didn't hear it running.
Not just once, but twice now.
With the highest electrical rate in the country, about $0.43/KWH, each night cost about $20 on the electrical bill.

So, I want to install an Intermatic WH40 - 24 Hour Mechanical Hot Water Heater Timer.
That should cut our electrical consumption and cure my leaving water running problem.

I want to mount the timer on the wall just below the junction box adding it between the box and the water heater.

I can get the 1/2" flexible conduit with 3 strands of #10 wire from HD.
But, the present install uses solid wire.
HD only carries #10 stranded wire.
I am reluctant to use stranded wire in place of solid.
I'm open to advice.

I always prefer stranded because it easier to work with (in my opinion ). Although Marrying solid and stranded under a wire nut can be tricky. If you want you can run to Romex (which is solid core ) inside of the MC for this short of a run.

I'm curious as to how you came up with that $20 figure. Even though it's a 4500 watt heater, it doesn't run constantly. Turning it off completely allows the water to cool and when you turn it back on, you have to reheat the 50 gallons. As opposed to leaving it on and have the elements turn on and off intermittently to keep the water at a set temp.
You should install tank insulation or switch to a tankless system.

Better would be a solinoid drivin valve that operates with a timer.

kok328 said:

I always prefer stranded because it easier to work with (in my opinion ). Although Marrying solid and stranded under a wire nut can be tricky. If you want you can run to Romex (which is solid core ) inside of the MC for this short of a run.

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When I get it finished I want it to look as if it had been done all at one time by one person, not like a Rube Goldberg.
I will probably have to get my materials from another source, and pay a bit more.
My reason for starting this post was not liking the thought of combining solid and stranded wires.

beachguy005 said:

I'm curious as to how you came up with that $20 figure. Even though it's a 4500 watt heater, it doesn't run constantly. Turning it off completely allows the water to cool and when you turn it back on, you have to reheat the 50 gallons. As opposed to leaving it on and have the elements turn on and off intermittently to keep the water at a set temp.
You should install tank insulation or switch to a tankless system.

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When the water is running constantly the heating elements will be on constantly as the water circulates through the tank constantly never getting up to temperature.
Our normal night time [sun down to sun up] electrical usage is 5KWH +/-1KWH. On the nights when I left the water running, the usage was 52KWH giving 47KWH @ $0.43 = $20.21.
It has taken 2 months to recoup the wasted power and get back into a negative usage again.
Rather than changing out the water heating system, I will be adding solar water heating in the near future. That will make our 4KW solar PV system way over-kill for our needs.
Then, we can run the hot tub, I can use a welder and a few other electrically powered items and stay within our ability to generate power.

We have had 2 major power outages in the last year.
last fall for 6 days and this winter for 3 days. Each after wind storms.
After the first one, we put in an emergency generator, for refrigeration and possibly clothes washing.
During the second outage, we had water warm enough for showers and kitchen uses for the 3 days, although the showers were getting pretty tepid by the 3rd day.

The power to the tank can be shut off say from 8pm until 6am every night.
The power consumption for hot water will be less than if it were left on without a very noticeable difference in available water temperatures.
turning a water heater off at night is a recognized way of cutting power usage.

nealtw said:

Better would be a solinoid drivin valve that operates with a timer.

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I have already bought the timer. It is the route I'll be going on this.
We have a 10k gal. catchment tank.
We have way more than enough water for our needs and it is virtually free.
I'm not very concerned about the wasted water.
The tank overflows every time it rains, and right now its raining heavily every night.
I left the wheelbarrow out the day before yesterday.
This morning it was full of rain water to within 4" of the top.

Where did you leave your water on overnight that it didn't register with you? You probably spent more on wasted water than just the electric used to run the heated water down the drain.

I would install one of these to shut the water off if you leave it running too long. They will also protect you if a washing machine hose breaks when no one is home.

http://www.thewateralarm.com/wateralarm/categories/Flood-Alarms-and-Water-Shutoffs/

Your timer idea isn't a bad idea, I had time of day electric service in my first house 30 years ago. Even with 4 people in the house I never ran out of hot water, my water heater was on a timer and only ran at night and on weekends.

Sparky617 said:

Where did you leave your water on overnight that it didn't register with you? You probably spent more on wasted water than just the electric used to run the heated water down the drain.

I would install one of these to shut the water off if you leave it running too long. They will also protect you if a washing machine hose breaks when no one is home.

http://www.thewateralarm.com/wateralarm/categories/Flood-Alarms-and-Water-Shutoffs/

Your timer idea isn't a bad idea, I had time of day electric service in my first house 30 years ago. Even with 4 people in the house I never ran out of hot water, my water heater was on a timer and only ran at night and on weekends.

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I had turned the water in the kitchen on to wash my late-night snacking dishes. I was waiting for the hot water to begin flowing when I was distracted and walked away.
Not just once but twice in a two month period.

As I stated in my answer to nealtw we're on catchment.
Our water is virtually free.

I worry more about the pump overheating or breaking when running constantly for 6 to 8 hours.
Something that would shut the pump off in this type of situation wouldn't be a bad idea.

I thought the link I provided had a solenoid valve that would turn the water off after a certain amount of time if the water was running continuously. I don't see one and haven't been able to find one that works without a leak detector. I don't think a leak detector in your kitchen sink is something that you're looking to use, as it wouldn't be that helpful. It would probably need to be set for continuous water flow for 30 or more minutes though if you were watering your lawn even that setting wouldn't be long enough. It would be long enough on the hot water only side since even the largest top loading washing machine can fill in less than 10 minutes.

Some one may make such a piece of gear, but I have yet to be able to find it.

I know equipment has been purchased so this may not apply but it could be interesting.
This unit can be set to run only when you hit a button or have a motion sensor in the room like a kitchen and turns itself off when hot water reaches the sink.

nealtw said:

I know equipment has been purchased so this may not apply but it could be interesting.
This unit can be set to run only when you hit a button or have a motion sensor in the room like a kitchen and turns itself off when hot water reaches the sink.

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Neal,
Did you mean to add a link to your post? I'm not sure what "this unit" you're referring too.

I have something like what Neal linked to in the above post. It would certainly reduce the wait for hot water at the sink. Before I installed one in our master bathroom we could run 5 gallons of water down the drain to get hot water for a shower. Our master bath is about as far away from the water heater as it could possibly be. I'm literally closer to my neighbor's water heater than to my own. With the pump we can run about two gallons out to get it hot enough for a shower, but it is always warm to wash your hands.