15 second lockout even though furnace is running normally?

parasomia

Hey everyone,

First off - thank you for all the information here. It has helped so much throughout the years.

My mom's furnace has started having an issue that just popped up. I've tried a few things and just am not sure what to look at next. For starters, I did change the oil filter and added a new pump to it a few weeks ago. The pump is a Suntec A2VA 7116. I only changed it because the old one was, well, getting old and figured I'd keep up on things for her. Everything has been fine until a few days ago. (I do not think this is a fuel pump issue of any kind. Just adding in changes made)

The other day she woke up to a cold house. I checked the furnace and hit the reset. Everything starts up fine and I can hear the flame ignite. Also checked through the peep hole to make sure it was there. No problem. But the system shuts it down after 15 seconds. I thought maybe the cad cell was bad. I bought a new one. Same problem. I used the old one on my furnace to test it and it hasn't been a problem.

Next thing I thought was maybe the primary control has gone bad. It is a Beckett GeniSys 7505A. I just got a new one in today. Same one - 7505A - Replaced it and redid the wiring as a just in case. Everything is connected the way it's supposed to be. Same thing is happening. I watched it and at first the green lights come on showing that it sees everything and it's all good. Then they turn off. They might flash on again for a second, but ultimately it locks out after the 15 seconds. It's as if the eye isn't sensing a flame? I don't know. Doesn't make sense.

In another twist, and I don't know how random this is, it'll work fine. In fact it was very cold in here on Sunday and when it decided to work, it ran for hours heating the house up just fine. Ran fine all day until sometime at night. 15 second lockout. Also, it is a Beckett AFG burner.

Sorry for the long post. I'd rather just see if anyone has any ideas instead of me tearing my hair out with it. Thank you for all you do!

mattmia2

Who adjusted the new oil pump and the burner when the oil pump was replaced?

parasomia

Sorry, it's a Beckett AF15 burner. Could it possible be the nozzle not putting out enough? I don't know when it was last replaced. I think it's a .60 80? I have a .65 80a laying around. I don't know if that would be good...

parasomia

No adjustments were made. I think the default settings matched what the burner called for? I'd have to check.

Jamie Hall

If you put in a new pump, and didn't check and adjust the pressure... oops. You need to verify that you have the correct nozzle for that burner and boiler combination, that it's firing at the correct pressure, and that ll your draughts and combustion results are correct. That takes test instruments -- it can't be done by eye. If you have the instruments and know how to use them, wonderful. If not -- it's tech. time.

mattmia2

It needs to eb adjusted by an oil burner tech. You really shouldn't attempt to operate it until you can get an oil burner tech to set it up properly. The nozzle selection and pressure set the firing rate.

HVACNUT

It's nice that you wanna help Mom. But to really help, you'll get her a seasoned oil tech. Changing the fuel pump without checking pressure and combustion is sacrilegious. Well maybe not that, but pretty close. 

parasomia

Thanks everyone for the advice and ideas. The nozzle size for that burner is a .60 80b. Which it has. I'm going to order a new one. As for the pump- I'll at least check the pressure when I pick a gauge up. The burner says it should be at 100psi. I'll report back when I find out. As for helping mom... Money is tight, that's why I helped. Most of the time when we try to get a heating guy out they either say they can't come out or they'll call back and don't seem to. But I'll ask around at work if anyone knows anyone.

Jamie Hall

It may well not have been set up for 100 psi -- higher pressure is more common. That affects all the rest of the adjustments, and as I said you cannot do it by eye -- and shouldn't attempt to do it without the test instruments.

BDR529

No solenoid? Need Pre-purge with Genisys or will lock out.

HVACNUT

BDR529 said:

No solenoid? Need Pre-purge with Genisys or will lock out.

The 7505A has no pre or post purge. The B has pre purge. The P has pre and post purge. 

heatandair

You should ohm out the cad cell before you go changing out more parts. Also check the burner coupling if it wasn't changed with the pump

SuperTech

If you are going to continue to fire the parts cannon at it then you should consider the electronic igniter/ignition transformer. That might solve it, it might not.  It might be safe to operate, it might not.  How much are you willing to leave up to chance on your mom's system? 

I would have been able to diagnose the problem correctly, perform repairs and a combustion analysis to make sure the equipment is operating safely all in one visit. It probably would have cost less than what you paid for all those random parts.

BDR529

HVACNUT said:

BDR529 said:

No solenoid? Need Pre-purge with Genisys or will lock out.

The 7505A has no pre or post purge. The B has pre purge. The P has pre and post purge. 



Been fooled before with the Genisys, even on the U model. Programmer in hand and can't set to application.

EdTheHeaterMan

@SuperTech, you forgot about throwing a burner coupling at the burner. You also missed new electrodes, 3/16" high pressure line might be a problem, the air adjustment bands could also be dirty. Perhaps the burner fan is loose on the motor. The wires from the Cad Cell holder can also go bad. What about the thermostat? If the burner is not getting the temperature up to the thermostat setting... it must be the thermostat. (I intentionally left out the oil filter and plugged oil lines because everyone knows that a new pump always fixes plugged fuel lines.)

And you say you could fix oil burners!

This post has been brought to you as a public service from:

mattmia2

I mean there is a 99% chance that the problem is it now is not burning properly because they replaced a perfectly functioning pump that was adjusted to that burner in that equipment with that nozzle with a new pump without having an oil burner tech adjust the new pump and burner.

EdTheHeaterMan

Is this in a mobile home or manufactured housing? Just guessing because money is tight and you have a .60 GPH nozzle. (is this redneck profiling). I apologize if I am politically incorrect, But the AFG burner comes in furnaces designed for manufactured housing and this information will help in the diagnosis.

I wonder if the fuel line is partially clogged? You can test it with a new Fuel Pump, New Primary Control and new Cad Cell eye, by just adding a vacuum gauge to the mix. You probably could check it with the old Primary control, old pump and old Cad Cell eye too.