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oil burner furnace question

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NutmegCT

NutmegCT

Great Pumpkin
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as it will take three days for the furnace repair guy to arrive ...

if the motor on the burner (not the fan, the burner) goes rapidly on and off w/o igniting - what's the likely cause?

New transformer.
New relay
New motor!
New pump
Old dummy home repairman ....

Wired up correctly, jet and electrodes adjusted correctly, oil flowing smoothly.

But power it up, turn it on, and the motor just cycles on/off until you shut it down. Never even ignites.

I can see the photocell shutting it down after no ignition in 20 seconds, but can't understand the motor going on and off immediately after turning the system on (and the thermostat is calling for heat).

yeesh

T.
PS - the motor goes on and off every second or so, like rapidly turning the power on and off. weirdamundo
 
I'm inclined to think relay, but it's been over 20 years now since I've had to worry about those furnace thingies :rolleyes: (it's well over 90* here right now, I can't imagine why you would need heat :devilgrin: !)
 
havn't had my furnace on since the middle of April (cheap I is)just put on an extra sweater
 
sounds like maybe a bad stack switch?

mark
 
Don't need heat here either! But the hot water comes from the furnace too (tankless heater).

Tried two other relays - same symptom.
No stack switch.

Wonder if the air/fuel adjustment is whacked? That'll be fun messing around with. I reset the electrode gap and distance from nozzle, checked the nozzle for flow and the transformer for spark. Argh. Next step is trying to guess the correct air band setting.

If you see a glow in the northeast, and don't see any further posts from me, you'll know I made a slight mal-adjustment ...

T.
 
What's a furnace? :devilgrin:
 
Tom: we use gas here but my son had heard that heating oil is going to "lock in" at over $4/gal. Have you locked in for next winter? Hos much?
 
No fuel in tank?
 
Sounds like it's out of fuel or, the pump went south or, the igniter isn't working. The stack switch is doing it's job if it's shutting down the burner as it takes heat to keep it in the on position. If there's fuel in the tank, I'd replace the igniter's first, as that's the cheapest way to go. If that doesn't work, and the pump has pressure, replace the nozzle. The nozzles have a fine screen on them that can get clogged by any foreign material in the fuel, even water.

PS, Check your inline fuel filter for water.
 
Thanks for the suggestions!

Here's the scoop at 8am today: there's no stack switch on the system, the fuel tank is nearly full, the pump pulls oil w/o problem, no air in system (I purged it yesterday), oil is pure, new transformer, new relay, new pump and new motor. Fuel nozzle at the igniter tip is clean and oil flow out when the pump turns.

Paul - when you say igniters, do you mean the electrodes? The electrode tips are set and gapped correctly.

Really puzzling to me that the motor (the burner motor) goes on and off rapidly. Power up the system, set thermostat to call for heat, motor goes on then turns off within two seconds, then goes on again, then off again, always on a "two second cycle". That's too fast for the photocell to be in the picture.

With all the new parts and the correct "oil flow", it seems like an electrical problem. But the wiring matches the setup manuals.

argh.

T.
 
How about the control box?

mark
 
Thanks Mark - sorry I'm dense. What is the "control box"?

The burner consists of motor, blower, and oilpump [edit: and transformer, oil nozzle and electrodes]. Mounted on that assembly is the relay, which electrically links the thermostat, mains power, transformer, burner-motor and photocell. The relay is labeled Honeywell R8184G Intermittent Ignition Protector Relay. The relay has the "red button" for system reset.

Is "control box" what Honeywell calls the relay?

Rest of the system is the boiler (firebox with water piping), power junction box (AC in, AC out), and thermostat.

One thing I don't understand about the system's wiring diagram. Diagram shows the mains' 120v AC "hot" wire going to a part of the diagram labelled "limit", then on to the relay box. On mine (as it has for 20 years), the incoming mains hot wire goes directly from the wall junction box to the relay. Don't know what the "limit" thing is.

Onward through the fog!

T.
 
The limit thing shuts the whole thing off if the blower doesn't operate on most furnaces.It often works in conjunction with the thermostat.That's the one that operates the blower.
The relay sounds like it is the control box on your system.
Some blowers have a reset button on them too.

Of course,I'm being very general here.And probably not being very helpful either. :rolleyes:

Stuart. :cheers:
 
have you checked the thermostat it self? are you using a standard thermostat? you could try removing it and jumper the wires together,,, or jumper them at the control box. if the problem still exits then it kinda has to be the control box

the control box runs the system, and watches for a signal from the photo cell. there are different delay times.
https://customer.honeywell.com/Hone...nnelID={2EB2F178-20ED-44E0-97FB-CCFB4218DD64}


there is an oil burner forum here
https://forum.doityourself.com/index.php

sounds like you have replaced just about everything. doesmt leave much else.


mark
 
Solved!

The new pump was bogus. I kept trying to figure why the motor would turn on and off, but all the electricals were OK.

So in desperation I pulled the entire oil pump off the motor assembly. Slowly turned it by hand, and felt some resistance about 5 degrees of each revolution.

I put on the *old* pump, which had no resistance when turned. Cranked the system back up and voila! It works! I can take a shower! yeehaa!

Thanks to all for your help. :thankyousign:

memo to self: next time (in 20 years) when I buy a new oil pump for my furnace, take it out of the box and turn it through a couple revolutions.

T.
 
now why would you go and do that? just slap whatever motor you have in a box and throw it on the shelf. in 20 years you will forget what the problem was with it and try to use it again. That's what makes life interesting. I've made dozens of 100+ mile trips in the past to re-replace a "new" part for customers who SWEAR over the phone that the part is new.... I've even pulled out "new" parts where someone wrote in huge black magic marker "BAD" or "BROKEN" on the part. (and some of them were in MY handwriting because the customer wouldn't let me throw it away the first time)

They'll even fish them out of the trash after I leave "just in case"....


:devilgrin:
 
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