primary control lights on fire.

justHEATit

I have a beckett burner af15 on a miller furnace cmf80-p0 and the primary control on the burner lit on fire and burned out. My question is what would make this happen.

justHEATit

There's gotta be something behind that happening, I do cars furnaces are cars without wheels lol. Oil nozzle? Electrode faulty transformer? The spark seems okay when I put screwdriver between them and touch and pull away it follows

Ironman

Find the short; maybe the motor?

HVACNUT

Pics?
How old?
Is it the older grey R8184G or is it a recent Miller with the Genysis primary?
Break out your meter and ohm out the primary, motor, transformer/igniter, oil delay valve if applicable through the controls and to ground.

There should be constant 115v to the primary via the door switch and limit. TT from the thermostat energizes the burner circuit.

justHEATit

You can see the burn marks from the fire on the reset switch casing, and yes its the older version honeywell. I'm just interested in what would cause it to catch fire???

EBEBRATT-Ed

Could be a defect in the control. Could be loose wires or a short, bad motor bad transformer, bad oil solenoid (if you have one). Check all components and wire them individually to test.

Under no circumstances run the burner other than while testing without a safety control on it

justHEATit

Can I run it without it being mounted like a car engine? And test for spark with power only going to that if I plug it in?

GBart

Seriously?

The relay contact got old, pitted, fried or may have had excessive amperage draw from another component, that caused amperage to go up which increases heat and it burned out, it didn't catch on fire.

It needs to be replaced and the burner properly checked out by a pro, you want me to give you 40 years of experience and training FOR FREE??

what do you do for a living? will you tell me everything you know about that?

ChrisJ

> @GBart said:
> Seriously?
>
> The relay contact got old, pitted, fried or may have had excessive amperage draw from another component, that caused amperage to go up which increases heat and it burned out, it didn't catch on fire.
>
> It needs to be replaced and the burner properly checked out by a pro, you want me to give you 40 years of experience and training FOR FREE??
>
> what do you do for a living? will you tell me everything you know about that?

You're on a forum called heating help. That's the entire point of it ...

STEVEusaPA

Any reason why you're not calling a professional and are willing to burn down your mobile home? I'm assuming mobile home because of the furnace.

justHEATit

Lol I know these burners iv3 done heating with my dad, I lay floors, build houses and work on cars. I'm a farmers boy.. just looking for input on why it would catch fire, which it did because I blew it out

Erin Holohan Haskell

GBart said:

It needs to be replaced and the burner properly checked out by a pro, you want me to give you 40 years of experience and training FOR FREE??

what do you do for a living? will you tell me everything you know about that?

@GBart - You've made this comment a couple of times this week, so I'd like to elaborate on what we're doing here. We've created Heating Help so that people can share knowledge and learn from each other. And yes, it's free, but it's a give and take. If you do not wish to share your knowledge, then you don't have to. Just don't disparage people who come here looking for advice.

GBart

I was being slightly sarcastic, but... Technicians learning from each other, yeah, but I don't think that everyone should try to give away all of our knowledge, some problems should go right to "call a qualified contractor, this above a DIY" and end. Some things could be explained and helpful especially if a consumer has recurring issues or may not believe what they are being told, but complicated issues like controls, especially primary/safety controls are not to be trifled with by DIY's, they are protecting the building and it's occupants from fire and explosion.

Help people sure, advise people sure, but certain areas should be left to pro's only, this aren't tinker toys or automobiles or appliances, they can cause serious damage, I advise everyone to be wary of what you suggest to who, they have a date and time and who told them to do what.

I'm really actually floored that rarely is anyone told to call a pro when dealing with gas regulators or safety controls or safety devices.

Steve Thompson (Taco)

Thanks Erin. You are right on the mark. Must have a proud papa I think...

Erin Holohan Haskell

@GBart, I understand your concern for safety. We’ve got a lot of smart and generous pros on here who often advise homeowners to consult a professional when the situation calls for it.

This forum is open to all and that includes DIY-ers. It is humbling to ask for help and that’s what people who come here are doing. What we don’t tolerate is disrespect.

If you’d prefer a forum that is for techs only, you can find that elsewhere. If you’d like to stay and participate, then follow the site rules. Thank you.

Now let’s get back on topic.

Tim McElwain

Gbart you would be very suprised by the number of homeowners who I contract who post here and advise them on gas safety and the importance of calling a professional.

justHEATit

Fuel pump seems okay. Motor spins with the little bit of resistance it should have. Is it possible for primary controls to just age out and stop working?

Steamhead

Might be an electrical problem. Was there a lightning strike nearby? Does your home have a Federal Pacific breaker panel?

EBEBRATT-Ed

Yes it could be just a bad control. What you should do (and only if comfortable doing this) is remove the burner motor and take off the pump coupling then put the motor back on the burner and wire the motor directly to the 120 volts. Turn the power on and run the motor, check the motor amps if you have an ammeter. It will be lower than normal beacause it is not driving the pump. If the motor seems ok, disconnect it and power up the ignition transformer only, with the transformer closed listen for the electrode spark. If the transformer is ok move on to the oil valve and see if it pulls in and drops out with the power switched on and off. If all the electrical components seem ok replace the control.

Have the burner adjusted with a combustion analyzer. Re assemble the burner and put the pump coupling back in.

Again, only do this if it's in your comfort zone

HVACNUT

It's more than likely just age on the primary and it's time was up. Happens a lot with the R8184G. Of course everything should be tested.

My personal favorite is when the customer follows you to the boiler, it's cold but not in safety. Give the primary a tap with my boot and she fires up.
That'll be $$ please.
But no, they get upgraded to a primary with a15 second safety. The 8184 safety time is 45 seconds.
And wired for interrupted ignition.

If your handy and feel confident, order a new primary.
Beckett, Honeywell and Carlin make replacement primary controls to replace the R8184G. Follow the directions carefully. Like like an engine on a lift.
You do NOT want pre and post purge.
How old is the furnace? Is it time for a complete upgrade?

Steamhead

HVACNUT said:

You do NOT want pre and post purge.

Why not?

justHEATit

We got a cmf #9311 (1993 11 month)in that case is it better to buy new parts and fix her up right or just drop the money and buy a furnace;cost wise. I've called for a new one on quote and it was $ but it seems replacing and cleaning could be better cost wise like my old ford.

HVACNUT

> @Steamhead said:
> You do NOT want pre and post purge.
>
> Why not?

Meaning if he were to replace the primary only. The existing R8184G is a standard intermittent ignition primary.
Theres no delayed oil valve there now, so no pre and post.

The newer Miller furnaces with the AFG have the Genysis primary and clean cut pump.

justHEATit

Also I'm looking at these parts and the filters are clean, transformer followed along with a screwdriver. The motor don't whine and pump too. The only thing I noticed was a Crack in the electrode and a ignition coil mark on the spark plate. Nozzle was dirty but filter was clean. It would need a new tube and burner head too.

justHEATit

Inside the combustion chamber is a little cracked but that's normal, I can always pull the burner plate and see inside too.

HVACNUT

> @justHEATit said:
> We got a cmf #9311 (1993 11 month)in that case is it better to buy new parts and fix her up right or just drop the money and buy a furnace;cost wise. I've called for a new one on quote and it was $ but it seems replacing and cleaning could be better cost wise like my old ford.

No pricing, no pricing.
This is a down flow Miller for a mobile home correct?
It's not cold yet. If it were me, and I planned on staying there at least 5 more years, I'd replace the whole furnace.
If you have nat gas or LP available, you could go with a Miller gas furnace.

Unlike the furnace, the Ford is worth salvaging.

justHEATit

The blowers runs fine too by manual, my flues fine inside and out (exhaust) little dust on blower easy clean up for me ill put it and shine it. Or like what u just said is it really nothing worth it? I was always taught that nothings ever broken.

Steamhead

HVACNUT said:

> @Steamhead said:

> You do NOT want pre and post purge.

>

> Why not?



Meaning if he were to replace the primary only. The existing R8184G is a standard intermittent ignition primary.

Theres no delayed oil valve there now, so no pre and post.



The newer Miller furnaces with the AFG have the Genysis primary and clean cut pump.

OK. If he uses a GeniSys or one of the other modern controls, it can be updated to operate the valve and at least do a pre-purge.

All our oil-fired units get this upgrade. If the fuel unit doesn't have a valve built-in, we use the Beckett #2182602 valve/PD Timer kit, which will fit just about anything.

justHEATit

I've just wired the primary to a cord and plugged it in, instantly lit on fire

HVACNUT

Listen, you just calm yourself down over there @justHEATit.

justHEATit

I'm doing it with safety, but in all regards u think it can't be refurbished up nice? I can do things with my hands! We gotta start teaching the generation now, they can't even read a tape measure.

justHEATit

I should tare this thing apart post some photos and get some input on whether to or not. In my opinion it seems worth it even if with the age, the only thing that scares me is all aftermarket parts.

justHEATit

New question: oil furnaces worth refurbishing?

justHEATit

Just called buddy from hvac on cardigan mountain up here in backwoods alexandria and he said a refurbish works as well as new with the right specs, but I assppreciate ur comments hvac and Steam.

HVACNUT

I dont know what to say anymore.

Steamhead

Cardigan Mountain in NH, correct?

I wouldn't use a refurbished R8184.

justHEATit

> @Steamhead said:
> Cardigan Mountain in NH, correct?
>
> I wouldn't use a refurbished R8184.

Yes and I was thinking rewiring the different primary... the parts will be new not refurbished. New parts but refurbished.

Good man Steve D