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Posted By: iwire Firematics - 10/18/03 10:56 PM
Is the use of firematics in a general building code or is it state by state?

As far as I can tell in MA a oil burner needs a firematic above it along with a disconnect switch at the top of the cellar stairs when the burner is in the cellar.

In RI it seems I need to install a firematic on gas furnaces.

Is there any standard that applies here?
Posted By: Electricmanscott Re: Firematics - 10/18/03 11:58 PM
Not sure about that one. Perhaps mechanical code? As for the switch I believe it must be located out of the room that houses the oil burner. If the burner is in an open basement the switch must be outside of the basement, such as on the first floor outside the door leading to the basement stairs.
Posted By: iwire Re: Firematics - 10/19/03 09:24 AM
It was brought to my attention that "Firematic" is most likely a brand name for the device I am talking about.

Problem is I do not know any other name for it.

It is essentially a heat detector with a single pole normally closed switch rated at 120 volts.

It is wired in series with the power supply to an oil burner in MA so that on temp rise the power to the burner will be cut off.

And now I am being told I need to install this for a gas fired furnace in RI.


[Linked Image from preferredutilities.com]
Posted By: Ryan_J Re: Firematics - 10/20/03 01:49 PM
Bob, I looked in the Interenational Mechanical Code and also the International Residential Code and couldn't find anything regarding this. All that I could find is a requirement for a shut-off valve, nothing electrical. Perhaps you have a state amendment to the code...?
Posted By: Bill Addiss Re: Firematics - 10/20/03 03:47 PM
Bob,

It may be required in NH too. My parents had to have one installed above their Oil-fired Hot-Air Furnace when the house was built 10 years or so ago. At that time the AHJ was the local Fire Marshall (if that makes a difference).

Bill
Posted By: gserve Re: Firematics - 11/09/03 12:22 AM
Guys I live in NH and they are required for oil and gas burners. They are thermo cut-out switchs. The type I see around here are black with a push in black "switch" which has a temp rating of I believe of 185 degrees which is supposed to melt at that temp and shut off the heating equipment(It is wired in series with the hot wire). This is also known as a "new england safety kit" which includes the fire-o-matic, a switch at the head of the basement stairs with red plate(oil or gas) and a fire-o-matic on the oil feed that looks like a black wheel and is used to shut off the flow of oil to the burner. This also has a temp rating and will melt if there is a fire and shut off the flow of oil to the burner.
Posted By: ThinkGood Re: Firematics - 11/09/03 10:01 PM
Question:

My house has a natural gas, hydronic (circulated hot water) baseboard heat system.

How would a switch help in an emergency? The only things electrical are the water circulation pump, the zone valves and the "clicker" to ignite the pilot.

Are the switches (for gas furnaces) meant for the forced hot-air type?

(I can understand an oil furnace having a switch--the oil is burnt by having it spun into a fine mist, correct? Stop the spinning and no more burning oil?)
Posted By: iwire Re: Firematics - 11/09/03 10:07 PM
Thinkgood thats how I understood it.

The burner motor along with fan adding air has an oil pump.

Stop the pump and no more oil.

As gserve has said it can be more to it.

In the house I grew up in there was a cable run through pulleys with melt out links in it from a valve on the oil tank across to the burner.

If a the cable was released the tank valve would close.

I have not seen this recently though.




[This message has been edited by iwire (edited 11-09-2003).]
Posted By: Speedy Petey Re: Firematics - 11/10/03 10:25 PM
Think Good,
You must still have 120v feeding the gas boiler, no? There is a x-fmr stepping down to control the gas valve. When you open the safety switch it closes the gas valve.
Posted By: condenseddave Re: Firematics - 11/24/03 05:58 AM
We install them over boilers here in PA, mostly out of habit anymore, I guess. Not all the wholesalers seem to carry them or even know what they are anymore...
Posted By: DougW Re: Firematics - 01/09/04 01:02 AM
Seems like an electric version of a 'thermocouple' - a heat/expanding aire pressure sensor to guarantee flame presence for a pilot fired gas burner. My dad changed over from oil fired to gas when we moved into our old house, and I remember having to swap them out every few years.

Nowdays, many control modules (Pilot? Why would I need to fly my boiler?) incorporate a "flame proof" (sensor), to ensure that there is, in fact, a burning flame, and not just a big cloud of gas vapors in your furnace/boiler. If the flame proof fails, it d/c's the power to the gas valve (solenoid), and shuts down the flow of gas. Usually, the chain of activity follows like this:

Thermostat calls for heat.
Pre-light gas flow (25% of "regular" flow for 5-10 secs)
Ignition fire (piezo for 5-10 secs)
Flame proof test-
Flame yes? then open valve rest of way.
Flame no? shut valve. Retry after 60-90 secs.
If burning, continue until thermostat is happy.

I assume that your Firematic operates in the same fashion.

I got to know the control module intimately due to a failure of mine one cold winter a few years back (!*#%^$( solid state (*&^#&!!!).
Posted By: iwire Re: Firematics - 01/09/04 08:08 AM
Doug No the firematic makes sure there is no flame. [Linked Image]

It goes above the burner on the celling or sometimes right on the front of the boiler or furnace.

It is a single pole switch that opens when heated.

It is more like a high temp cut out, it kills all power to the boiler controls.

Bob
Posted By: earlydean Re: Firematics - 01/09/04 09:02 PM
The High-limit pictured in this thread is not required by any code. NFPA 13, standard of installation for oil burners, recommends the installation of this device. I always install one anyway, though.
Posted By: DougW Re: Firematics - 01/10/04 02:18 PM
Aaaah... sorry, missed that one.

I can understand a requirement for oil furnace (given poss. of spilled fuel), but for a NG/LP application?

Any gaseous fuel burning outside the furnace should burn off quickly. (Of course, if it's a broken pipe, shutting off the furnace won't really help much I suppose)
Posted By: CTwireman Re: Firematics - 04/20/04 01:04 AM
Like Bob, I work in the states he mentioned (MA, RI)

I too don't understand why this would be required for a gas furnace, as the gas valve allready has a safety device built in. These devices aren't required above gas-fired water heaters or other gas fired appliances, so why would a furnace need one?

I have always installed them due to tradition but I won't anymore if I can find the applicable code references.

Also, the safety switch often installed at the top of the basement stairs or just outside the boiler room is another one that confuses me.

The firomatic requirement for an oil burner makes sense though, and is always done around here.

Peter
Posted By: Ryan_J Re: Firematics - 04/20/04 02:50 AM
Like I said before, I really don't know anything about these because it is a non-issue in my area. Here is something from the NFPA 54 (National Fuel Gas Code) handbook, however. (Bold added by me)

Quote
The following commentary was taken from the NFGC NFPA-54-2002 Handbook:

"The National Electrical Code requires a separate electrical circuit and over current protection for central heating equipment, as well as a means for disconnecting the power source at or within sight from the appliance. This separate circuit also can include circulating water pumps, valves, humidifiers, electronic air cleaners, and other accessories normally associated with the equipment. Certain appliances and installations also are permitted to be connected with a flexible cord that has a grounding-type attachment plug. The grounding-type attachment plug also serves as a disconnecting means for future service & maintenance. In subsection 8.6.4, note the phrase "a permanently live electrical circuit --that is, one that is not controlled by a light switch." This requirement thus prohibits "emergency shutoff" switches. In areas where oil is a common source of heating fuel, wall switches with red cover plates marked "Oil Burner Emergency Switch" are installed in buildings heated by fuel oil, as required by NFPA-31, Standard for the Installation of Oil-Burning Equipment, to stop the flow of oil to the burner. When converting an oil furnace or boiler to gas, the emergency switch must be removed. Emergency switches must not be installed when installing a new gas boiler. The emergency shutoff switch provides safety for oil-fired heating equipment, because failure of the boiler or furnace to shut off can prevent the oil pump from shutting off, thereby filling the equipment and surrounding area with oil. An oil pool fire is possibile. With gas-fuelded equipment, the emergency shutoff valve required in subsection 6.9.3 provides equivalent safety.
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