gas water heater circuit

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arits74

Senior Member
Location
dixie arkansas
Occupation
working owner electrician
does a instant gas water heater have to have a circuit of its own,i have read the articles about appliances and cant seem to find the answer
 
The load is likely minimal, just controls and possibly a small draft blower. There are instances where the branch circuit switch or breaker may be allowed to be the disconnecting means, but you may want a separate disconnect for the WH so that you don't turn off other loads when working on the WH. Otherwise I don't see why it can not be on with other items, as long as those items are not required to be on a circuit of their own.

I am not familiar with these units but would not be suprised if some come with cord and plug - if so there is your disconnect.
 
stickboy1375 said:
Thats not instant though, they maintain water temperature but have an electronic ignition vs standing pilot...
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I think he is talking about a tankless water heater, which is for the most part is instant - it heats the water as it is used rather than storing hot water.
 
hurk27 said:
I do, almost all gas fired tankless I have wired for had a 120/15a cord and plug for the controls, if it was electric then I would agree with you but the OP said "gas"
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An electric unit would need to have at least ten to fifteen NEMA 5-15 cord caps on it in most cases:cool:
 
arits74 said:
does a instant gas water heater have to have a circuit of its own,i have read the articles about appliances and cant seem to find the answer
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While it doesn't have to be on it's own circuit, it's good practice to isolate it from other loads. This way you avoid the Sunday night phone call when the customer doesn't have hot water because something else on the circuit is tripping the breaker.
 
Speshulk said:
While it doesn't have to be on it's own circuit, it's good practice to isolate it from other loads. This way you avoid the Sunday night phone call when the customer doesn't have hot water because something else on the circuit is tripping the breaker.
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its actually in a small garage on a custom home.the garage is on the opposite end of the home as the panel,there is already 2 circuits in this garage.the circuit the water heater is on has 2 other receptacles on it and i didnt want to pull another circuit all the way to the end of the house just so the water heater would be on its on circuit.
 
arits74 said:
its actually in a small garage on a custom home.the garage is on the opposite end of the home as the panel,there is already 2 circuits in this garage.the circuit the water heater is on has 2 other receptacles on it and i didnt want to pull another circuit all the way to the end of the house just so the water heater would be on its on circuit.
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You are fine. Don't install another circuit. The gas fired tankless water heaters do not draw that much current.
 
kwired said:
I think he is talking about a tankless water heater, which is for the most part is instant - it heats the water as it is used rather than storing hot water.
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Those are called "on demand"

They are NOT "instant". It takes longer to get hot water to the faucet than from the old style storage type tanks.
 
kbsparky said:
Those are called "on demand"

They are NOT "instant". It takes longer to get hot water to the faucet than from the old style storage type tanks.
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Well the biggest difference in the concept of what makes one "instant" is how much water line needs to be purged before hot water reaches the faucet. You can have fairly "instant" hot water from a tank type heater if you have a circulating system to ensure there is hot water near every fixture ready for use.

On demand needs to be able to raise the temperature of the water as it is used, a so called "instant" water heater needs to be able to do the same. The rate of flow and amount of temperature rise needed is the biggest difference between one heater to the next, otherwise they both heat the water only as it is flowing to the fixture.
 
Good grief ... do some folks think they have to re-invent the dictionary every day? Or is it their way of trying to be the smartest mule in the paddock?

"Instant." All this quibbling over the meaning of 'instant.' Do the answers have any bearing onthe OP's question? does ANY means of heating water require a dedicated circuit?

I would submit that no, they do not - within limitations that you can derive from your load calculations. In practice, this would mean a 30-amp 240v heater gets its' own circuit, while a 5-amp 120v heater does not.

How can a practical heater require only a few amps of 120? Well, I can think of two ways.

One is the method others have described; the actual heat is supplied by a flame, and the electric power is just used for ignition and control. Yes, there can be more 'control' than just lighting the flame; dampers can be opened, the burner compartment purged, the size of the flame varied depending on water flow.

Another small heater is the brick-sized point of use heater, mounted right at a sink, to provide a very modest amount of hot water for washing hands. This type is often found in ... you guessed it ... garages. UL lists these cord & plug connected water heaters up to a five gallon capacity.

To answer the OP's question, I'd say 'no special circuit is required.'
 
renosteinke said:
Good grief ... do some folks think they have to re-invent the dictionary every day? Or is it their way of trying to be the smartest mule in the paddock?
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Well that is fairly normal here, and when talking to potentially the entire world sometimes clarification is needed on what may seem simple to some, others may not be familiar with a term or an item that is out there. I think you have been involved in some of this activity yourself at times:angel:
 
This has nothing to do with being the smartest mule.

There IS a big difference between "instant" and "on-demand"

Too often, a customer will specify an on demand system typically a Rinnai unit, thinking they will have "instant" hot water. They may be disappointed in that it takes longer for the water to get hot at the kitchen or bathroom faucet, since it starts out from a cold flow, and cold tank, etc. and has to heat the water, purge the pipes, etc. Install a flow restrictor and it takes even longer for the hot water to arrive.

The best selling point of such a system is that you never run out of hot water, not that it's "instant" at the tap.

Unless running out of hot water has been an issue, I never recommend such systems to my customers.
 
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