PowerFlame JR50A Issues

mugen

Need some help with a powerflame burner. Burner keeps going off on pilot ignition issue. Units always runs after reseting. Never been in front of unit when it goes off. Have little experience with these burners. 

Unit does have a unusual issue which I think is related to problem. When unit starts high amounts of CO can be read coming out of sleeve that covers blast tube. Boiler is positive pressure but should exhaust be coming out where blast tube enters chamber?

Also when I run burner with pilot only flame signal is 2.2vDC at control. Should signal be at around 5vDV before main burner ignites. Seems kind of low to me. 

Also when you adjust pilot flame should damper be slightly opened before main gas valve opens or is it okay to be fully closed while pilot is lite? Manual says one damper blade should be slightly open for pilot flame. 

Any advice would be greatly appreciated. Powerflame very hard to get a hold off. 

EBEBRATT-Ed

One damper should be roughly 1/4" open. It should not be leaking fumes around the blast tube. 2.2vdc is on the low side is this a UV detector or Flame rod? Honeywell 7800 control?

I don't remember the lowest the signal can go but most control MFGs whatever the minimum signal they say you have to have a higher signal to make the burner reliable. 5.0 is max I believe. @.2 sounds like they low end.

Pilots on PFs tent to be tricky. Take the pilot assembly out and clean it good. Adjust the gap on the electrode. Then get the pilot lit and put the control on hold and watch the signal. Make sure the electrode wire is good.

Play with the air setting and with the pilot reg to get the best (and steadiest signal) steady is important a
signal jumping from lo-hi is worse that a lower signal that is steady

And lastly. Check the 120 volts. Don't forget and a lot of techs don't realize this. If you ignition trand is rated 120/600 you only get the 6000 if you feed it with 120. Feed it with 115 you only get 5700out.

If ll else fails and you can't find the issue try a larger IG trans Webster used to make a 120/8500 volt singl pole. Not sure if that is still available. That used to fix the PF "C" burner when they had pilot issues.

Never had too many issues with the J but never worked on as many of those.

Work on those to get a stable signal and if you achieve that then maybe the transformer.

Propane or NG? Some utilities when the weather gets cold "shave the gas" by adding propane to the NG which can cause issues. Did this just start having problems?


What does the signal come up to when the Main Flame is on?

mugen

Thanks for the reply great info. 
The signal goes to 4.6vDC when main burner lights. Natural Gas. 
Both dampers are fully closed on pilot light off.
But signal is stable. 
Yes,  issue just started to happen last year. Eveeytime we clean flame rod and it runs for about a week or 2 then it's off in morning. Boiler is Smith which runs under pos pressure. Adjusted pressure with baffle in back of boiler.

Flame rod is coded white when we go back.upon immediate start up I get 200ppm CO coming out around blast tube and flange space which seems odd. I was thinking poor combustion is coating flame sensor? 

mugen

7800 controll 

retiredguy

What type boiler is this burner installed on? what is the MFG of the boiler? Can you post a picture of the boiler and burner? There should not be any air or combustion gases coming out or leaking out from around the burner and if there is the burner mount needs to be sealed better and/or the boiler pressure may be too high. Need more information on the boiler/burner.

mugen

HBsmith positive pressure 

mugen

28a series 

mugen

I adjusted positive pressure to smith specs using baffle in back 

ScottSecor

I am surprised you are able to get decent numbers with the air shutter basically closed and positive pressure over fire. I believe PF recommends 1/4" air shutter opening at a minimum as @EBEBRATT-Ed suggested earlier. In my mind, if you have the boiler under positive pressure you and the air shutter practically closed you have no where near enough air for a reliable pilot.

You might consider removing the burner and properly sealing the burner mounting plate and verifying the blast tube is protected from heat. While the burner is removed, inspect the diffuser plate, they do go bad on occasion.

I suspect your pilot flame is weak and "lazy." Instead, I think you may want a stable and strong flame. If memory serves (with two people), you can have one person read the flame signal while the other person examines the pilot flame from the rear sight glass on the back of the boiler.

Is there any chance this boiler was originally oil fired and the gas burner installer did not clean the fireside of the boiler? If this is the case, you may find the boiler still needs to be cleaned and the flame characteristics will likely change afterwards.

tim smith

Intermittent failures can be the bain of our existence. Check the burner manual for flame rod location, my guess is it has a 90 degree bend at pilot end. Usually they are say 10-15 degrees above center of pilot blast hole. The manual will show you flame rod orientation. Also, one of the more obscure intermittent problems we have had is a pilot solenoid hanging up and not fully opening. Real pain to catch. Sometimes just had to pick the 1st target to shoot at. Weak ignition transformer sometimes. Crack in electrode ceramic? On and on and on. Good luck.

retiredguy

Remember, that positive pressure is only at the maximum firing rate. That said, I rarely set those boilers to fire at a positive pressure over fire. A slightly negative pressure overfire always worked better for me. I never liked the 28 series Smith boiler anyway. If you have combustion gasses coming out of the firebox around the burner mount something is wrong. Did you install the gasket? If you can't find the gasket you can use braided rope.

mugen

Okay, went back today. Removed Burner found hole blown through diffuser plate, and plate concave like pushed out, and blast tube missing piece at end. I suppose due to this hole that's causing poor combustion  and causing flame sensor to coat over. 

Couple of questions: 

Should air damper be fully closed or slightly open in pilot light position? I've been told closed then been told slightly open? Also is it possible to get flame signal close to 5vDC with pilot only or around 2.0-3.0vDC more realistic?

Burner plate says manifold pressure 3.12"WC. Do I adjust to that then adjust combustion with air damper only or must I adjust pressure and air damper blades? 

Burner only runs in high fire, do I adjust combustion only in high fire because there's no way to lock in low fire? 

mugen

Retiredguy I don't understand how to make it negative? Would that be by opening baffle in back all the way to back pressure? 

mugen

Tim Smith followed manual with pilot burner set up. Igniter 3/16 pointed to plate not at orifice head. Flame sensor 3/8 above plate. 

ScottSecor

I believe the manual for the J burner recommends 1/4" opening for one air shutter. While this may seem like a lot of air, we have found this gives us a stable reliable pilot flame and smooth light-off. With regard to the flame signal, we typically see 2.5vdc to 3.0vdc on pilot and almost always 5.0vdc on main flame.

In the perfect world you would add an additional control to utilize that low fire for longer to prevent short cycling (if even possible, depends on gas actuators). In the real world, focus on dialing in high fire only as it likely is in high fire mode more than ninety nine percent of the time.

EBEBRATT-Ed

Flame rods suck. You will have much better luck with a UV detector but you probably have to change the amplifier. And that would be a few bucks.

You need to get the burner fixed up before you can fix the pilot.

You can run the boiler with Positive or neg in the fire box I have confirmed that with Smith years ago. There literature says positive because it improves the efficiency about 1%.

You need 1 damper open about 1/4". If this is a burner that starts on lo fire and runs (and stays) on high fire (lo fire start ) you don't need to test low fire. just high.

mugen

Thanks for the replies much appreciated.