Oil Primary Control Reliability issue

DWallis

So mom's furnace is on the blink again. Its a Lennox O23Q3/4-105/120-6A upright furnace with a Becket AFII-85 burner. So far I have replaced the oil primary 3 times. The first was a becket 7505b-1500. Second was a Honeywell 7184B1024(also a Becket part). Third is a Honeywell 7284u1004 with Enviracom. The error I'm getting on this last one is a "Enviracom Communications Error". It is supposed to automatically reset itself but isn't happening. The furnace is in a dry basement. In the summer it is kind of damp but mom keeps her dehumidifier going all the time. I pulled the cover off the back of one of the old controls to see if there was any condensation damage and found none. Anyone have any comments or ideas. Primary voiltage is 127 and secondary is 27 volts. Has anyone found one primary to be a little hardier than the others?
Thanks in advance.
Darin

Jamie Hall

Those units have a goodly complement of electronic whizbangs in them. Which leads me to the first thought that comes to mind: how clean is your power supply? Doesn't take all that much in terms of spikes, voltage dropouts, or just plain crummy power to make them lose their minds... with that many failures in close succession, that would be the first thing that hit me.

Don't rely on your power supplier's pious statements to the effect that their power is perfect. It isn't, even when it leaves the generator -- and by the time it gets to your site it may be pretty bad. Power conditioner or UPS?

lchmb

Another thought...check your neutral and building ground.. are you getting any stray voltage..

STEVEusaPA

Properly installed components usually last quite a long time. Many older burners/furnaces/boilers aren't properly grounded. Newer electronic controls require proper grounding.
Another problem may be improper venting, dirty heat exchanger and/or poor draft causing heat build up during the run cycle, and/or after shut down.
Electronic components don't like excess heat either.

Jamie Hall

lchmb said:

Another thought...check your neutral and building ground.. are you getting any stray voltage..

Agh yes. Hadn't thought of a bad neutral (and not necessarily on the burner circuit -- anywhere on the building side of the transformer will do it). That can give some huge voltage spikes or drops. And a bad ground (never mind a missing one) is simply lethal to digital electronics.

DWallis

Morning all. This goes back to my "hardier" comment. The house is in a rural location near the end of the line as far as power goes. Voltage spikes, lightning strikes and outages (Oh My!!) are common. Sometimes we need to fire up the generator to make it through a bad snow or rain storm. Knowing that dirty voltage can play havoc on some controls that I believe are over-engineered and have functions I'll never use is kind of a waste to me as well as inconvenient if the module goes bad. Other things aside I think I need to relocate the control or put a shield over top because I know there isn't a chimney cap on top and think rain water may be coming down it and dripping onto the board. Still curious about a reliable replacement without all the bells. Thanks
Darin

DWallis

BTW Cabinet is grounded to the panel. House was built in 1970 and has a Cutler-Hammer panel using 12 gg solid wire

Jamie Hall

I quite agree with you about fancy controls which are fragile. Seems to be the coming thing.

Do put some sort of moisture shield over the control or relocate it -- it doesn't take much moisture to ruin these things. For power, though, I would look into a UPS such as one might use to run a computer through. They aren't really all that expensive, and they solve a whole lot of problems with dubious power.

Steamhead

DWallis said:

The error I'm getting on this last one is a "Enviracom Communications Error".

What, if anything, is hooked to the Envirocom terminals on the control?

Steamhead

Here is the manual, showing the various error codes:

https://customer.honeywell.com/resources/techlit/TechLitDocuments/69-0000s/69-2467EFS.pdf

An EnviroCom error can also be a low voltage error. You might want to get hold of a recording voltmeter to see what's going on with the incoming power, and get after the power company if the problem is on their end.

Low voltage can cause delayed ignition, which can make the burner "puff" on start-up. This is NOT a good thing.

Robert O'Brien

These aren't "fragile" controls. They have been in the field for many years, well over a million in total. Something is wrong with the installation or site conditions

Jamie Hall

In defense of my comment. Fragile is a relative term. In relation to some things, your are quite right, @Robert O'Brien -- they've been used for a long time quite successfully. As you note, they are, however, sensitive to site conditions or installation problems in a way that a simple SPDT switch (think pressuretrol or bimetal Aquastat -- never mind a Honeywell T87) isn't. Specifically, "dirty" power can cause problems. A bad neutral somewhere in the local system can cause problems. A bad ground. That's all I meant.

GBart

"Other things aside I think I need to relocate the control or put a shield over top because I know there isn't a chimney cap on top and think rain water may be coming down it and dripping onto the board."

woah, these controls, any of them, CANNOT GET WET OR DAMP, that is why they are failing, and no "hardier" control is going to fix this

you are running the risk of serious injury, home damage, or death, any oil or gas safety control that has gotten wet MUST be replaced

the controls are defaulted to test memory at start up and if they don't pass muster they lock themselves out

GBart

Robert O'Brien said:

These aren't "fragile" controls. They have been in the field for many years, well over a million in total. Something is wrong with the installation or site conditions

please see my comment above

Leonard

Lighting stikes are a likely canidate. Had ones that blew out our TV, but may have been caused by voltage difference between comcast TV and power cables.

Had a ~ 1 amp continuously on roof ice melting cable, fused it at 3 amps. Found fuse had blown couple times months apart, no lighting here in winter.Everything looked good, can only assume it was a voltage surge. Was powered off a HVAC power line, but in winter AC pump (the MAIN HVAC load) didn't run, only blower motor for gas hot air. Was a restaurant on a MAIN city street. 120/208 3 phase 400 amp service, HUGE pole transformer only <200 ft away

If you think have voltage spikes maybe put a whole house surge suppressor at the breaker panel. supposedly they have a higher Joule rating than those computer power strip ones. Only thing is I think all of them clip at ~ 330V , not sure on that number. Sine wave peak of 120VAC is 170V

To be specific , Technically not ground but a bad or lost neutral can cause huge voltage swings ( utility line from street doesn't have a ground wire only the neutral wire (at ground potential). We had a bad one once, some lights were dim others super bright, utility used a outdoor crimp connector on neutral that they latter found liked to corrode.

GBart

Leonard said:

Lighting stikes are a likely canidate. Had ones that blew out our TV, but may have been caused by voltage difference between comcast TV and power cables.

Had a ~ 1 amp continuously on roof ice melting cable, fused it at 3 amps. Found fuse had blown couple times months apart, no lighting here in winter.Everything looked good, can only assume it was a voltage surge. Was powered off a HVAC power line, but in winter AC pump (the MAIN HVAC load) didn't run, only blower motor for gas hot air. Was a restaurant on a MAIN city street. 120/208 3 phase 400 amp service, HUGE pole transformer only <200 ft away

If you think have voltage spikes maybe put a whole house surge suppressor at the breaker panel. supposedly they have a higher Joule rating than those computer power strip ones. Only thing is I think all of them clip at ~ 330V , not sure on that number. Sine wave peak of 120VAC is 170V

To be specific , Technically not ground but a bad or lost neutral can cause huge voltage swings ( utility line from street doesn't have a ground wire only the neutral wire (at ground potential). We had a bad one once, some lights were dim others super bright, utility used a outdoor crimp connector on neutral that they latter found liked to corrode. </p>

doubt it, read my comment above, his controls have been getting wet, game over

DWallis

I don't know they've been getting wet, I suspect they may have been getting wet. I'm just asking if others have noticed issues in rural areas with the primary control. If the controls have been proven reliable in normal conditions, I will look for other suspects which include but not limited to possible water dripping from the vent. I haven't seen it, I suspect it(highly). Thanks for all the help.

GBart

Technically our controls are solid as a rock, all the bad ones were weeded out long ago.

Also look into a whole house surge suppressor.