Boiler Flame Lockout
Gennady you know your stuff… drock2750: if you understand the following then you will be able to troubleshoot the burner in order to eliminate if you are having a control issue.. If you don’t understand what the hell it all means or even where it comes from. Stop and call a commercial burner service company. Most (not all) won’t know how to approach these relays. 1.Constant 120 VAC should be available to the Ll-L2 terminals only on the wiring base.
2\. The operating control circuits (Ll-13) will close, signaling the burner to start its firing sequence.
3\. If the fuel valve end switch (13-3) is closed, the burner/blower motor (terminal M) circuit is
energized. The running interlock (limit) circuit (3-P) will close (e.g. all limits, interlocks, etc.
are proven).
4\. The firing rate motor (Modulator Motor) is driven toward the high purge open damper position
(10-X circuit made).
5\. When the firing rate motor reaches its open damper position, the Hi Purge switch closes (D-8)
and the prepurge interval of 30 seconds is initiated.The ED510 will display:
PURGE 0:05
HIGH FIRE PURGE
If the D-8 circuit does not close, the program will hold in this position for ten minutes waiting for it
to close. If it does not, the control will lockout.
6\. When the prepurge is completed, the firing rate motor is driven toward the low purge damper
position (10-12 ckt. made). The ED510 will display:
PURGE 0:35
LOW FIRE PURGE
7\. Following the minimum 30 second delay (to permit the firing rate motor to get to the low fire
position), the control will wait for the low fire switch (M-D) to close. When it closes, the trial for
ignition sequence will start. If after ten minutes, the M-D circuit is not closed, the control will
lockout. The EPD167 will wait indefinitely for the M-D circuit to close. 8\. The trial for ignition period begins with Terminal 5 and 6 being energized simultaneously. This
is known as PTFI (Pilot Trial for Ignition). The ED510 will display:
PTFI 0:02
IGNITION TIMING
This period is ten seconds in duration. If no flame is detected after ten seconds, the control will deenergize
Terminals 5 and 6 and lockout. When flame is detected during this 10 second period, the
ED510 will display
PTFI 20
FLAME SIGNAL
9\. With flame proven at the end of PTFI, the main flame trial for ignition (MTFI) period begins.
Terminal 7 is energized. The ED510 will display:
MTFI 35
FLAME SIGNAL
Terminal 5 is de-energized 10 seconds later and Terminal 6 is de-energized after another 5 seconds.
10\. The firing rate motor is now sent to the auto position (10-11 ckt made) and is under the command
of the proportional controller. The ED510 will display:
AUTO 40
FLAME SIGNAL
steam_man
in Boiler Repair 13 years and 8 months ago
4
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4 replies
drock2750 | 13 years and 8 months ago
I have a question related to the pressuretrol on my boiler… I have set the pressuretrol to approx 2psi, but here’s the problem: When the boiler control calls for heat, the draft inducer comes on for a couple minutes before the gas valve opens…I assume there is some sort of pressure switch to prove that the inducer is on,like on a gas furnace. Once the pressure gets too high, the pressuretrol kills boiler, but when the pressure then drops and the boiler comes back up, the draft inducer once again runs for a couple minutes before the flame comes on. By this time, all the pressure in the system is lost…it seems pretty difficult to control the pressure in this situation. Am I missing something? Do most boilers take so long to fire the burner once the system/pressuretrol calls for heat? BTW, the boiler is a 1997 Kewanee with a Gordon Piatt burner at 2 million btus.
Master Plvmber | 13 years and 8 months ago
You could lower the differential on the pressuretrol to shorten that off time, but you don’t need constant pressure to make heat. The reason for a pressuretrol is to create a dip in pressure which allows the air vents to open up, so it’s necessary for steam travel. Honestly, it sounds like what you really need is more or better air vents to lengthen your burner’s run time on the initial call for heat.
eman134 | 13 years and 8 months ago
how quickly are the mains heating up?
ellenlourie | 13 years and 8 months ago
you have 60 BHP boiler. so this is apartment building. Why are you trying to deal with commercial boiler yourself and not calling heating professional? There are lots of factors affecting proper boiler operation and without proper training when trying to set up steam system, you can get more than you bargain for.