Gas unit heater

[olly]

Does a fixed in place gas unit heater for a garage need to be on its own circuit. 422.12 states only central heating needs its own circuit. Not sure If I am missing it somewhere else in code?

 

[retirede]

Only if specified in the manufacturer’s instructions.

 

[texie]

And it will if it is more than 50% of the branch circuit.

 

[retirede]

And it will if it is more than 50% of the branch circuit.

True, but unlikely for a gas unit.

 

[WasGSOHM]

So how many amps does it draw? 1A for a fan?

 

[kwired]

My thoughts are no, it is not a central heating unit. Still do need to consider that 50% of the circuit thing, but keep in mind that would only apply to circuits that also serve receptacle outlets.

 

[Dennis Alwon]

Imo, it is a central heating system

422.12 Central Heating Equipment. Central heating equipment
other than fixed electric space-heating equipment shall
be supplied by an individual branch circuit.

 

[K8MHZ]

IMHO, if the furnace is in the same room (space) it is heating, and no other rooms or spaces are being heated via ductwork, it's a space heater. If multiple rooms were served by a single furnace via ductwork, to me, that would be central heating.

 

[Dennis Alwon]

You all are playing games with semantics. That is fine however it will probably be as Texie stated.

(2) Utilization Equipment Fastened in Place. The total rating
of utilization equipment fastened in place, other than luminaires,
shall not exceed 50 percent of the branch-circuit ampere
rating where lighting units, cord-and-plug-connected utilization
equipment not fastened in place, or both, are also supplied.

 

[WasGSOHM]

You all are playing games with semantics.

I thought the NEC was designed to minimize ambiguity.

 

[Dennis Alwon]

I thought the NEC was designed to minimize ambiguity.

Have you read it.....?LOL

 

[WasGSOHM]

Have you read it.....?LOL

Point taken!

Minimal ambiguity might not be possible, given the complexity and number of all the situations it covers.
Maybe if they split it into several volumes?

 

[retirede]

Semantics or ambiguity or whatever.
There are plenty of examples in the NEC, but I can’t fathom considering a single heater heating the space it’s installed in as a “central heating system”.

But that’s just my opinion.

 

[Dennis Alwon]

Maybe I am wrong but I am thinking this gas heater is a small sized furnace that could be used as a central unit. In that case why would it matter that it is used for a single area and not multiple rooms?

 

[retirede]

Maybe I am wrong but I am thinking this gas heater is a small sized furnace that could be used as a central unit. In that case why would it matter that it is used for a single area and not multiple rooms?

I envisioned one of those ceiling or wall-mounted units. Especially since the title of the thread mentions “unit” heater.

I’d hate to lose garage floor space to a furnace.

 

[WasGSOHM]

I could see leaving the NEC iffy: mental inertia, bigger fish to fry and so on. But how 'bout fighting to keep it iffy, like for "wiggle room"?

 

[kwired]

IMHO, if the furnace is in the same room (space) it is heating, and no other rooms or spaces are being heated via ductwork, it's a space heater. If multiple rooms were served by a single furnace via ductwork, to me, that would be central heating.

I agree. It is a space heater and not a central heating unit as it only intended to heat one room/area. If used in a one room building maybe there is more to debate about, but most of what is intended for "central heating" is designed to have ducts, pipes, etc. attached to it to distribute that heat to different areas of the building. Such unit can be a boiler that has very little electrical load and piping to distribute that heat to other areas of building.

 

[kwired]

I envisioned one of those ceiling or wall-mounted units. Especially since the title of the thread mentions “unit” heater.

I’d hate to lose garage floor space to a furnace.

That another reason, they are usually called "unit heaters", I believe that this means they are self contained and not designed to directly provide heat for another space. Central units don't heat the space they are located in unless you put some sort of outlet on the method you are distributing the heat with within that space.

Line can be more blurry with a boiler system, typical fan coil on this system that only heats one room - not a stand alone central system. Put one those duct heater style units that uses boiler as heat source in and could be somewhat of a hybrid as it may have characteristics of both.

 

[Frank DuVal]

Maybe I am wrong but I am thinking this gas heater is a small sized furnace that could be used as a central unit.

Not as designed! One would have to add ductwork to a louvered front panel to make a UNIT heater feed multiple rooms.




I'll duck back out before someone mentions floor furnaces (a real one, not a furnace mounted ON a floor).... Never saw one of those on a separate circuit either. Always dimmed the lights on the circuit they were on.

 

[kwired]

Not as designed! One would have to add ductwork to a louvered front panel to make a UNIT heater feed multiple rooms.


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I'll duck back out before someone mentions floor furnaces (a real one, not a furnace mounted ON a floor).... Never saw one of those on a separate circuit either. Always dimmed the lights on the circuit they were on.

My grandparents house had a floor furnace, or I suppose maybe it was just a "unit heater", though there was no other heaters in the other rooms of their fairly small house. It had no electric supply, just gas supply and thermostat and gas valve driven from thermopile on the pilot light, natural convection heat distribution that come up through a grate in the floor, and not a great thing to have small children around. More than one grandkid had been burned on that thing. Pobably some of their parents when they were little as well.