r7284U hard lockout issues

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  #1  
Old 07-06-13, 06:48 PM
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r7284U hard lockout issues

Hello,
This is the first time posting on this forum. Apologizes for any mistakes that i might make.

We have a Buderus oil burner with logamatic control and a honeywell r7284U primary ignition control unit (installed about 6 months ago) and a beckett motor.

The system is about 8 years old and we get the yearly service performed.
Since about a week now, we'v noticed that the system seems to be locking out. I reset the system by pressing the reset for two seconds and it fires up.

The burner reaches the the desired temperature and shuts off (approx 139 degrees). Once it reaches 129~130 degrees, i see that the system calls for heat, and the display on the r7284U shows that, then it displays "valve on delay" for 15 seconds and then it is supposed to ignite, but that doesn't happen. it goes to hard lockout.

Scrolling through the errors on the display unit, i see it says: "flame proven ON during valve-on-delay". the instruction manual mentioned to check the oil valve.

I had a technician stop by and clean out the clean cut oil valve filter, bled the line and restarted the system. It ran fine for several cycles and it locked out again.

I would really like some advice on how to go about diagnosing / fixing this problem once and for all. Really frustrating.

Could it be the solenoid ? If you need pictures, i can post them for you.

Look forward to hearing from the experts out there.
 
  #2  
Old 07-06-13, 07:37 PM
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A little clarification first. You have a Buderus boiler with a Beckett oil burner. The Honeywell R7484U is a primary control (leave out the ignition part as the control does far more than just ignition).

The Honeywell R7484 has what Honeywell calls "safe start". On a call for heat the control first checks to see if there is already a flame in the combustion chamber. If there is the control will go into lockout. If no flame then it energizes the burner motor ONLY and will run for a preset period of time in what is called prepurge. (Also called oil valve delay). This is to remove any unburnt gases from the combustion chamber. After this delay the ignition transformer and the oil solenoid valve are energized and under normal conditions the oil is ignited. Then a stabilization period ensues after which the ignition transformer is de-energized. Now the burner is operating normally.

Now it is possible that your R7484 was wired to energize the ignition with the motor AND it is possible you have a leaking oil solenoid valve. The combination COULD cause a premature flame during the purge cycle and THAT would cause the system to go into lockout. You need to closely observe if there is any flame present before the 15 second delay period. If there is the control is working as it should. However, if the control locks out on a regular basis with NO flame present then it could be a problem in the wiring of the flame sensor or even the flame sensor itself. After checking thoroughly the wiring and changing the sensor if it continues to lock out with no flame then the control is bad.
 
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Old 07-06-13, 09:22 PM
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Hi Furd,
Thank you for replying so quickly and for the clarification. Yes it's a Buderus boiler with a Beckett oil burner. the control, however is R7284 (with the digital read out).

Your description of the process is absolutely spot on. When i get the system out of lockout, i see the "call for heat" message on the display, then i hear the burner motor run (valve on delay for about 15 seconds), and then i see it ignite (seeing the flame through the glass window on the boiler). Flame proven message and then RUNNING message. it's on the restart when it locks out.

How can i test the solenoid valve ? i see that it's part of the Beckett cleancut oil valve. Is it something that can be replaced or the entire assembly will need to be replaced ? If i have to test the solenoid valve, what should be the resistance when testing with an ohm meter ?

According to the troubleshooting guide error message that i click through on the honeywell primary control unit, it says "Flame Proven During On Delay" and to check the oil valve for proper operation.

Thank you.
 
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Old 07-06-13, 09:45 PM
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hi. i just checked the resistance on the solenoid and it is reading about 447ohms.

Also, the system had been running fine for the past 4 months (no lockout even once). I don't see any oil on the floor under the oil valve? could the leak be internally ? what's the average life of a cleancut oil valve ?

this is all new to me hence so many questions. not to mention exciting and learning a lot from this forum.

thanks.
 
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Old 07-06-13, 11:10 PM
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I actually know very little about residential equipment having spent my thirty plus year career with commercial and industrial sized equipment. Grady is the expert on these matters and hopefully he will pop in.

I do remember Grady saying he wouldn't give a dollar for an entire truckload of Cleancut pumps. The resistance reading you got on the coil of the oil solenoid valve is of little meaning. The coil is simply an electromagnet that open the valve proper. It could be a tiny speck of dirt is keeping the valve from fully closing and that is allowing fuel to get past the valve before the electromagnet is energized. That fuel would enter the combustion chamber and IF it is in an atomized state AND sprays close enough to the igniter electrodes could be the early flame the sensor cell "sees" and causes the Honeywell control to enact a safety shutdown.
 
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Old 07-09-13, 08:33 AM
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Hi Furd,
If that were the case, valve not fully closing, then i should have someone remove the valve stem and clean it / change it. What i find strange is that after it has been shutdown for a few hours, i press the reset button on the primary control and the system starts up. it runs till the boiler reaches it's set temperature (approx 139 degrees) and then it shuts down. i've kept checking and when the temperature drops to about 130 or 129 degress, the boiler control calls for heat and that's when it seems to lockout. If the valve has a leak, SHOULD it start for even ONE cycle ? just curious.

hs
 
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Old 07-09-13, 11:10 AM
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I know a fair amount about Honeywell controllers but my knowledge of residential oil burners pretty much stops in 1980. I have asked Grady to look at this thread.
 
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Old 07-09-13, 06:31 PM
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I don't know what kind of resitance you should be seeing with the solenoid. Beckett (Suntec) has had a lot of trouble with those clean cut pumps.
I know the solenoid is replaceable as is the cord set but I'm not sure about the valve body.
I have not beenn a proponent of the clean cut pump valve arrangement since I had several stick open. The clean cut does not have an internal valve but relys solely on the electro-mechanical solenoid valve. I much prefer Suntec's A2VA-3006 which has both an internal cut-off & the solenoid.
 
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Old 07-09-13, 07:58 PM
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Thanks Grady.

A few more questions please. Will the Suntec pump work with valve-on-delay (15 seconds set on my honeywell primary control) ?

What questions do i need to ask the next time i call a service person to come and look at the system ? i.e. how to determine if he/she is the right person for the job ? not having much luck in that area so far.

i'm really looking to get this resolved for good.

thanks.
 
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Old 07-09-13, 08:00 PM
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Thanks, Grady. I didn't know these pumps didn't have the internal oil valve. Just for that reason alone I would strongly urge hsingh to change out the pump.


I think you will have to get an add-on solenoid valve for the new pump.
 
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Old 07-09-13, 08:12 PM
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The Suntec will work just fine since it has an external solenoid valve in addition to the internal mechanical valve.
It's the only pump I use in residential applications.

Oil burner techs, especially good ones, are literally a dying breed. If your oil supplier has a service department, talk to the service manager & tell him/her about your burner problem. In nearly every company of any size there's at least one tech who kind of specializes in 'problem' burners.
 
 

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