# cord and plug gas water heater



## farmantenna (Nov 22, 2012)

new installation I saw three large commercial gas fired water heaters, for apartment building etc, connected with electrician-made 12-3 SOJ cords with 20-amp straight blade plug and single receptacles somewhat behind the heaters and something tells me it isn't right but probably is ok. 

422-33 says the attachment fitting must be factory installed part of the appliance and suitable for disconnection. The heaters also have a small manufacturer installed unit switch. I've never connected these like this but looks easier this way. But I see issues over time with the cord caps and connector if plumbers are using them repeatedly. I don't know.


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## HackWork (Oct 2, 2009)

> 422.16 Flexible Cords.
> (A) General. Flexible cord shall be permitted (1) for the
> connection of appliances to facilitate their frequent interchange
> or to prevent the transmission of noise or vibration or
> ...


I doubt the documentation for the water heater say it could be installed with a flexible cord.


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## splatz (May 23, 2015)

I don't see a manufacturer blessing it but it seems like a good setup. All of the little point of use water heaters I see come with a factory plug.


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## MechanicalDVR (Dec 29, 2007)

splatz said:


> I don't see a manufacturer blessing it but it seems like a good setup. All of the little point of use water heaters I see come with a factory plug.


Yes and I have also seen a larger sidewall vent type heater that also comes with a factory installed cord.


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## RePhase277 (Feb 5, 2008)

Leave it alone. The cord will last longer than the cheapo breaker they would use to turn it off.


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## joebanana (Dec 21, 2010)

A "gas" water heater, with an attachment plug? GAS water heater that plugs in? To an electrical outlet?
I don't get it.


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## nrp3 (Jan 24, 2009)

There are quite a few power vented tank gas water heaters and tankless that come with cords. Had one at the last house I owned.


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## MechanicalDVR (Dec 29, 2007)

joebanana said:


> A "gas" water heater, with an attachment plug? GAS water heater that plugs in? To an electrical outlet?
> I don't get it.


Many of the newer high efficiency units have flue dampers, draft fans, and electronic ignitions.

I don't recall any that drew over 2 amps total so I was surprised to read the units in question were on 20 amp circuits.


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## joebanana (Dec 21, 2010)

nrp3 said:


> There are quite a few power vented tank gas water heaters and tankless that come with cords. Had one at the last house I owned.


I just replaced my gas water heater a little over a year ago, and it didn't come with a cord. In fact none of the gas models that I looked at had one. This must be a Canadian thing. :blink:


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## Switched (Dec 23, 2012)

joebanana said:


> I just replaced my gas water heater a little over a year ago, and it didn't come with a cord. In fact none of the gas models that I looked at had one. This must be a Canadian thing. :blink:


If you got it at HD that would explain why... 

They have some really cool things on WH now that create a ton more efficiency, like the new heat pump water heaters... Those are cool.


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## Forge Boyz (Nov 7, 2014)

joebanana said:


> I just replaced my gas water heater a little over a year ago, and it didn't come with a cord. In fact none of the gas models that I looked at had one. This must be a Canadian thing. :blink:


It's for the power vent water heaters. They have a fan on them for the exhaust. The advantage with them is they don't have a very hot exhaust and you can use PVC pipe to vent them instead of going into a chimney.


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## MechanicalDVR (Dec 29, 2007)

joebanana said:


> I just replaced my gas water heater a little over a year ago, and it didn't come with a cord. In fact none of the gas models that I looked at had one. This must be a Canadian thing. :blink:


Not at all, the biggest manufacturers in the US all make these type models.

Look at any brand sidewall vent model.


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## MTW (Aug 28, 2013)

Power damper is required now on 85+ gallon heaters to reduce standby loss up the chimney.


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## inetdog (Apr 13, 2016)

MTW said:


> Power damper is required now on 85+ gallon heaters to reduce standby loss up the chimney.


The high efficiency side vent models do not, AFAIK, need that because they operate with a fan-forced draft when the burner turns on.

Sent from my XT1585 using Tapatalk


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## MechanicalDVR (Dec 29, 2007)

inetdog said:


> The high efficiency side vent models do not, AFAIK, need that because they operate with a fan-forced draft when the burner turns on.
> 
> Sent from my XT1585 using Tapatalk


Some still have dampers to stop natural hot to cold transfer up the exhaust piping.


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## inetdog (Apr 13, 2016)

MechanicalDVR said:


> Some still have dampers to stop natural hot to cold transfer up the exhaust piping.


Not a lot of convection in a horizontal pipe....

Sent from my XT1585 using Tapatalk


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## MechanicalDVR (Dec 29, 2007)

inetdog said:


> Not a lot of convection in a horizontal pipe....
> 
> Sent from my XT1585 using Tapatalk


Hot will go to cold, it's just basic thermodynamics.


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## inetdog (Apr 13, 2016)

MechanicalDVR said:


> Hot will go to cold, it's just basic thermodynamics.


By conduction and radiation, yes. By convection, which could be stopped by a damper, no unless there is a vertical component to the gas or fluid motion.

Sent from my XT1585 using Tapatalk


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## MechanicalDVR (Dec 29, 2007)

inetdog said:


> By conduction and radiation, yes. By convection, which could be stopped by a damper, no unless there is a vertical component to the gas or fluid motion.
> 
> Sent from my XT1585 using Tapatalk


There is an internal flue (normally 4" dia minimum) inside a water heater that is open for combustion air at the base. 

The air at the base of the heater is cooler than the water surrounding the flue, therefore as that air is heated with in the flue it will rise to the top of the heater and gradually heat the exhaust fan components and radiate that heat back into the surrounding space at the top of the heater. 

This effect can also cause condensation to form on the exhaust fan components and the top of the heater in specific humidity and temperature conditions causing premature rusting of these components. 

There is your lesson in water heater technology today.


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## frenchelectrican (Mar 15, 2007)

MechanicalDVR said:


> Some still have dampers to stop natural hot to cold transfer up the exhaust piping.


I have see that with larger gas water heaters and guess what some of the oil fired water heaters over here now have dampers on it too .,, 

I just got one done today hook up a new circuit for oil fired water heater ., ya it did have a damper on the top .,


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