Weil Mclain EG-75-PI with ignition problem question

Glenn Harrison

Nope, no spill switches. I should add that neither the module or the gas valve looses power at any time. Also when the pilot "snuffs" out, the main burner still stays lit for a ½ to 1 second as the module flame sensing relizes that the pilot is out.

Glenn Harrison

I have a customer with a Weil Mclain EG-75-PI (300,000 B.T.U.) boiler, about 15 years old. About 4 or 5 years ago, customer had another contractor clean boiler. After the cleaning, the boiler would lite the pilot, and lite the main burner with no problem. 2 to 3 seconds later, the pilot would dissapear and burners would shut off, pilot would be relit by elecetronic ign. and repeat several times. The number of times this would repeat seems to be dependant on how cold the burners are, as in if the burners are off for a long time, the sequence may repeat for 10 to 15 times, but if burners have only been off for a few minutes, the sequence will only occur once or twice, or maybe not at all. The ignition system was originaly the White Rodgers mercury filled pilot sensor system with electronic pilot lite. I replaced all this with W.M. authorized spark to pilot parts, (step opening gas valve, spark ign.module, and pilot burner) which did not correct the problem. I have checked the inlet gas pressure (6.7" fired), the manifold pressure is 3.4", flue draft just above hood is .02", C.O. is at 40ppm and O² is 5%. As I said, the problem is the pilot "snuffs" out shortly after the main burner lites, but the problem goes away as the burners warm up and the system runs. Any suggestions for fixing this one would be greatly appreciated.

Thanks,
Glenn

John@Reliable

W/m ignition

I don't know this unit but it sounds like a spill switch or sensor some where maybe?

gas man

pilot problems

1st- would recommended a ground wire from module to pilot mounting screw , possible flame rectification problem , check house pressure, and try bringing pressure down to 5-6'' or so ,6 to 7'' could cause pilot to lift off burner !please try grd 1st , I'LL WATCH FOR RESPONSE ! ALSO DOES THE UNIT REACT THE SAME WAY WHEN FRONT COVER IS ON ? LAST BUT NOT LEAST -GO TO A STANDING PILOT ,THE BOILER WOULD BE HAPPY !

Unknown

Weil McLain Boiler

Did Weil McLain offer the retrofit as a solution to the problem that existed with White Rodgers Cycle Pilot? I first of all do not recommend trying to lower inlet pressure to gas valve. The pressure that comes to the valve is usually controlled by the house regulator if a high pressure system. If this is low pressure then that pressure varies with the pressure in the main in the street and there is no way you can change that. The house regulator should only be adjusted by the Gas Company. Having said that all pilots on modern combination gas valves are on line pressure, there is usually a pilot adjusting screw on the gas valve that will allow you to adjust the flow of gas to the pilot. The flame should envelope the upper 1/2" to 3/8" of the sensing rod. The flame should be a soft blue flame, make sure it is not roaring as this could cause it to lift off and this would cause your problem.

When the system is cold connect a microamp meter in series with the sensor wire or burner ground and control module (it would help if I knew the retrofit replacement controls) having done that put all doors in place and simulate conditions as they normally are when this occurs. It is also a good idea to hook up your "U" gauge to check gas pressure at this time to see if any drastic changes occur when the burner comes on. Bring the system on and watch the microamps they should be between 2 - 10 microamps, normal is about 3 to 5. Let the burner run watch to see what happens to microamps when this flame failure occurs. If the microamps start to fluctuate it means that you have a combustion problem occuring in the chamber, this often ocurs when the chamber is cold and then as it heats up it will go away. At the same time you are doing this take an overfire draft at the burner area make sure it is at least a -.02" WC at all times if it starts to go toward the positive while the burner is running then during that cleaning something in the sections or boiler could have been disturbed. If it starts to go higher -.03, -.04 ,-.05 then this indicates that the flame may be pulled away from the sensor causing it to flame fail. The problem existed before you did the retrofit and obvilosly it still does. That tends to make me think the problem is not controls. What still remains, the gas that seems to be okay, the boiler, chimney, the room itself lack of air, and perhaps what they did when they cleaned the boiler. Did they remove some baffle or plate in the sections? Why did they have to clean the boiler was it carboned up or just a routine cleaning? As was mentioned in another post and I repeat it here for emphasis make sure you have a good burner ground. If you are able to make this happen when you are there then take a jumper wire and go directly from the pilot to the gas valve (gas valve is a good ground)it the problem stops then install a permanent jumper, that would indicate that the existing ground was not adequate. I have a Troubleshooting Guide which would be helpful to you in going through all these checks. If you are interested let me know it is $6.00 plus S&H.

Mark Hunt

I think gas man has it. I have seen this before. Check the ground on the ignition control.

Mark H

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gas man

pilot problems

Gas man has returned - the reason why I mentioned adjusting the pressure is it seamed it may have been done so already, reason being its' on the high side . utility's usually give between 4 to 6 '' w.c. as the regulators are preset. A regulator supplying 6-7'' w.c. is not the norm. right now I believe its the ground . If that doesn't do the trick , when did the problem start ? Like Timmie stated ,was something removed ,as in baffle - and yes valves has adjusting screws for pilot's ,as they usually are on line pressure ! find out why a gas boiler needed cleaning !

Mark Hunt

I think you nailed it the first time Gas man. It's probably the ground.

ALL combustion appliances NEED to be cleaned, gas or oil.

My guess is theta the service tech that cleaned it moved something inadvertantly.

Mark H

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Glenn Harrison

First, let me say thanks to Timmie and gas man for your responses. To gas man, you are correct, there is a flame rectification problem. The pilot goes out with the main burners lit causing there to be no flame to be rectified. I hope I don't sound like a smart butt by saying that, but it's the truth. Pilot lites, main burner lites, pilot disappears, flame rectification stops, main burner turned off by ign module, pilot relites, process repeats anywhere from once to 10 times or more depending on when the last time the burners were on and how hot the burners and burner area is. Yes it reacts the same way wether the burner and or access covers are on or off. I did adjust the pilot flame from full gas pressure all the way down to so small the sensor could not sense the flame. I don't think I dare convert to standing pilot as the customer will have to be reliting the pilot constantly.

To Timmie. I replaced the controls due to the fact that (A) the controls had been over cycled due to this problem, and they are 15 years old, (B) It is the White Rodgers Mercury pilot systems which I am not fond of and don't trust for good flame saftey. These are all Weil parts. The gas valve is Honeywell V8300 series step opening, the module is a USC I believe, it looks just like a S8600 but only has a 10 to 15 second ignition trial with 1 attempt before 5 minute lockout. This is a residential system, low pressure gas, and I can say that 6" - 7" inlet is the norm around here. I would be very nervous about 5" inlet due to most valves needing 4.5" minimum to maintain the 3.5" manifold. I didn't take a microamp reading due to the obviousness of the pilot snuffing out. I did not take an overfire draft so that will be next. I can't imagine it being higher than -.02" because that is my chimney draft, but it could be dropping below -.02". As far as the cleaning goes, it was supposed to be the standard winter cleaning that the customer gets done every year since the unit was put in. What happened on this particular cleaning i don't know and probably will never know. I do know that the pilot is in the proper location in the burner rack. I don't know if there were ever baffles in this unit, but there aren't now. I have to agree that it's a combustion problem. The trick is determining the "problem" and fixing it. I guess someone who is more familiar with EG units than I am would be very helpful here.

I also should add that this ca'nt be a flame rectification problem anyways because this happend with the old mercury filled ignition system and that system doesn't use rectification at all.

Glenn Harrison

I have to agree, Mark. The tech from 5 years ago did something to this unit, the question is what. I'm hoping someone out there is familiar with EG units and cam tell me whether these units are supossed to have baffles or if there is something specific to look for in this model of boiler.

Mark Hunt

No baffles in those units!!!

I have installed and serviced EG's and EGH's and just about EVERY othe WM product out there.

No BAFFLES!!!!! Check the ground wire from the module!!

And ALL BOILERS should be cleaned EVERY YEAR!!!!!!

Hope this helps!!

Mark H

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Unknown

Weil McLain Rep in NE

is Dave Walsh at 508-478-6800 Ext 14 FAX 508-478-6869. Give him a call tell him you got his name from me. He should be able to connect you up with someone in the Illinois area. I wish you were nearby I would come and give you a hand. By the way I do not agree with cleaning GAS boilers every year but that is another subject.

Unknown

A suggestion in the meantime

install a S8610U continous retry this will eventually light for the customer as it attempts to light for 90 seconds then shuts off for five minutes then trys again just keeps doing that until it lights. This will keep it from going into lockout. The S8610U can be used with Natural and LP gas.

Glenn Harrison

Sorry, Timmie. I should have said the module does attempt to relite after 5 minutes of lockout. The unit never gets to "lockout" anyways, as the pilot relites 2 to 3 seconds after the main burner goes out after the pilot has been lost. The unit does continually relite itself until the burners warm up so at least the customer does not have to reset the unit. What bugs the customer is that they can hear the unit fire everytime in the living room over the boiler.

Glenn Harrison

Thanks for the number. I did contact Weil in Indiana when I was there. The first suggestion they had also was adjust the pilot flame. No luck. I unfortunatly ran out of time at the call on friday (had another appointment)and the customer did not tell the office that the boiler still had a problem when she scheduled the cleaning. I will have to call tech services back again on monday for more ideas. I just thought I would run this by the Wallies and see what suggestioins came up.

I would be interested in hearing your opinions on why not to claen a gas boiler every year. Maybe you could start a new post here on that one and let the opinions fly

Glenn Harrison

Thanks Mark. O.K. that eliminates one posibility. Any other suggestion out there?

D lux_2

how bout dirty P light

Might have a speck or to of dirt in orifce ? and gas pres. drops when main comes on p light drops enought to miss senc. I like the Grn. too I think I would try a new Plight W/ grn wire .cost not to high

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Floyd

Check this out...

I have found that over a period of time amd after many heating and cooling cycles,
that the hood over the pilot flame will tend to straighten out from the heat ing and
cooling of the metal on one side more than the other.
I know some of the people here would cringe at the thought af doing this, but it
has worked for me. Take your needle nose and bend the hood tighter to the sensor.
What happens is that when the flame on the main burner lights the draft pulls the pilot
flame from the sensor, this of course is worse when the boiler is cold and after a while
it doesn't pull so hard and the main burner stays lit. By bending the hood you can hold
flame on the sensor better.
You said the manifold press. was 3.4, have you timered the meter for input??? I'm thinking
3.0 is what should be for that boiler, and that may help out.
Did you change the pilot assembly when you switched ignitions??? If so, then maybe I'm
all wet here and it is something else, just get down there and watch the pilot flame when
she lights off....
These things are a real pain in the butt..... It's so much easier when they just plain don't
work!!!!

Anyway hope that you can get something to work.... perseverance!!!!!!

Floyd

Glenn Harrison

I did replace the pilot burner and tubing with the valve and module.

Thanks for the suggestion.

Glenn Harrison

Sorry to say but I did replace the pilot assembly and pilot tubing with the valve and module. I didn't clock the meter. Here's the kicker. The pilot goes out when the valve is still in the first step of the step opening procedure of the valve. This means that there is 1.5" going to burners for a few seconds, so its actually fired at 1/3 capacity and it still sucks out the pilot.

gas man

I'm back

things to check ,check ''pressure''on start up w/manometer -the service regulator may be slow allowing the pressure to drop enough to effect the pilot - - is meter inside or out ? - is vent clear ? Is there a voltage drop across the gas valve on start up - ? now let's get tricky - if your comfortable w/ this - !!fire up and when pilot goes out - have match ready (long enough or liteing rod ) see if there's gas there at the pilot - you see now where trouble shooting what's been installed - ok to try parts -if they don't work I put old ones back ! until problem is found ! alot of times if the cover is off ,electronic ingnition acts -up - .makes it a pain to observe- are air shutters on main burners wide open - if they can be adjusted = close them up to halfway and see what happens. Right now it seems module is doing its' job - turn gas valve to pilot - does it lite quickly and stay lit - (spark stops soon after ) if seems the problem is with the pilot and whats' causing it to drop out - gas pressure , voltage drop ,excess draft - if all these ideas prove ok - take a piece of metal (shield ) about 1 1/2'' wide - (like weil mc lains' HSI igniter shield- mount to pilot assembly - bend shield out and directly over pilot burner , be sure it's not impingeing on main burners - see what happens -when trouble shooting -when adjusting or changing parts - if it doesn't work -put it back and then continue - and last thought for know - shut off all fans - open windows - does it react the same ! later !

D lux_2

Put a T

in the 1/4 plight tube ck pres. when it drops out maybe something is going on or off in side the GV ? Gas pres doesnt drop below 6'' on input side of GV do you have a good used standing Plight GV to temp install ? just to watch ?

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D lux_2

What about A voltage prob.

Are you holding 24V on plight selenoid ? or is it droping or down out ? what gauge wire on tstat is the transformer large enough ?ck the amp draw on the gas valve does it change when the p light drops out let us know when you get it fixed .

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