1940_dodge Posted January 15, 2015 Report Share Posted January 15, 2015 (edited) I have a Roberts Gordon 80k BTU heater in my garage that has just recently started to backfire. When it is trying to ignite, it makes two loud bangs back to back and then stops trying to ignite until the next cycle. Anyone ever had a problem like this? It was recently converted over to natural gas using the kit from the manufacturer. I'm wondering if its a gas inlet setting that is off, or if there is a leak in the pressure valve. **Edit** This usually happens when it is very cold 10 deg Fahrenheit or below. Edited January 15, 2015 by 1940_dodge Quote Link to comment Share on other sites More sharing options...
Dave72dt Posted January 15, 2015 Report Share Posted January 15, 2015 Natural or LP? different size nozzles for each, natural takes a bigger nozzle. what type ignition? temp sensor on my furnace needed to be cleaned once when it started acting up like that. Had a bit of carbon buildup on the end of it. Quote Link to comment Share on other sites More sharing options...
Don Coatney Posted January 15, 2015 Report Share Posted January 15, 2015 Personally if I were having a such a problem I would contact the manufacture and ask for there advice. And I don't think I would be using the device until it were fixed. Quote Link to comment Share on other sites More sharing options...
Plymouthy Adams Posted January 15, 2015 Report Share Posted January 15, 2015 IF indeed it is gas fired, I would check the fire box cloosely for a void in the combustion chamber..it seems air may be entering from somewhere other than the manifold...carbon monoxide levels are also greatly increased in output where the firebox is not burning properly due to air/fuel ration being off this condition is usually easily noticeable by the improper flame color and burn profile Quote Link to comment Share on other sites More sharing options...
1940_dodge Posted January 15, 2015 Author Report Share Posted January 15, 2015 (edited) Natural or LP? different size nozzles for each, natural takes a bigger nozzle. what type ignition? temp sensor on my furnace needed to be cleaned once when it started acting up like that. Had a bit of carbon buildup on the end of it. It's Natural Gas, I made the conversion last month and definitely see a lot more soot on the exhaust chimney than with the year of propane I've used prior. IF indeed it is gas fired, I would check the fire box cloosely for a void in the combustion chamber..it seems air may be entering from somewhere other than the manifold...carbon monoxide levels are also greatly increased in output where the firebox is not burning properly due to air/fuel ration being off this condition is usually easily noticeable by the improper flame color and burn profile The conversion kit said to make 11 rotations on the replacement screw/spring. So that's all I have really to gauge if the mixture is correct. Looking through the observation window the flame is blue/orange directly above it. Edited January 15, 2015 by 1940_dodge Quote Link to comment Share on other sites More sharing options...
Plymouthy Adams Posted January 15, 2015 Report Share Posted January 15, 2015 (edited) did your conversion include the proper nozzle for the fuel inlet? and if it did...did you adjust the air flow to match that of the new fuel requirement... Edited January 15, 2015 by Plymouthy Adams Quote Link to comment Share on other sites More sharing options...
1940_dodge Posted January 15, 2015 Author Report Share Posted January 15, 2015 (edited) did your conversion include the proper nozzle for the fuel inlet? and if it did...did you adjust the air flow to match that of the new fuel requirement... It did, it was a larger diameter hole than the one that was replaced and it came from the Roberts Gordon distributor local to me as a kit. **Edit** Did not adjust the air flow though, there was no mention of that in the guide that came with it. It has a one speed fan that draws the air in to the combustion chamber. Edited January 15, 2015 by 1940_dodge Quote Link to comment Share on other sites More sharing options...
Dave72dt Posted January 15, 2015 Report Share Posted January 15, 2015 I thought it was supposed to be blue. Orange in it makes me think it running rich, not enough air. Inlet and outlet to outside air? Have you checked them for blockage? Is their a photo eye in it? May be dirty. Quote Link to comment Share on other sites More sharing options...
1940_dodge Posted January 15, 2015 Author Report Share Posted January 15, 2015 (edited) I thought it was supposed to be blue. Orange in it makes me think it running rich, not enough air. Inlet and outlet to outside air? Have you checked them for blockage? Is their a photo eye in it? May be dirty. That would explain it blowing itself out when it tries to ignite. I'll check later tonight and see what I can find, thanks. If the photo eye checks for flame, it uses a sensor that extends close to the actual flame as far as I know. Edited January 15, 2015 by 1940_dodge Quote Link to comment Share on other sites More sharing options...
1940_dodge Posted January 15, 2015 Author Report Share Posted January 15, 2015 IF indeed it is gas fired, I would check the fire box cloosely for a void in the combustion chamber..it seems air may be entering from somewhere other than the manifold...carbon monoxide levels are also greatly increased in output where the firebox is not burning properly due to air/fuel ration being off this condition is usually easily noticeable by the improper flame color and burn profile The box has test port for a manometer, is there a standard that it should read to? Quote Link to comment Share on other sites More sharing options...
Plymouthy Adams Posted January 15, 2015 Report Share Posted January 15, 2015 1940_dodge, on 15 Jan 2015 - 1:59 PM, said:The box has test port for a manometer, is there a standard that it should read to? there is specification and if dual fuel should be covered in the owner/operation manual..this should have also been described in detail in any conversion kit offered for that model. If you do not have these documents and verified the settings as per fuel being used...you may be able to download them off the internet. If not there, there should be an 1-800 number with the conversion kit to help with the conversion process to assure operation safety to the appliance and the end user. Quote Link to comment Share on other sites More sharing options...
Dave72dt Posted January 15, 2015 Report Share Posted January 15, 2015 That info should show up in the owners manual . If not, it may be time to contact your local distributor or dealer, either for troubleshooting, specs or actual repair. You should not be getting soot.. Remember, this is the clean burn fuel, with the little blue flame. Quote Link to comment Share on other sites More sharing options...
Don Coatney Posted January 15, 2015 Report Share Posted January 15, 2015 1940_dodge, on 15 Jan 2015 - 1:33 PM, said: It has a one speed fan that draws the air in to the combustion chamber. Does that fan blow air into the combustion chamber or into the heat exchanger? Quote Link to comment Share on other sites More sharing options...
Dave72dt Posted January 15, 2015 Report Share Posted January 15, 2015 That fan Don mentioned could be another problem area. My furnace (house) has a fan on the exhaust side to evac any unburnt gas fumes before it heats the ceramic ignitor. there's also a sensor in line that tells the control board the fan is running. My old furnace had a small vacuum line on that sensor that would occasionally develop a crack in it and not signal the board that the fan was running and then no ignition. Lots of things can cause your problem as you can see Quote Link to comment Share on other sites More sharing options...
1940_dodge Posted January 15, 2015 Author Report Share Posted January 15, 2015 Does that fan blow air into the combustion chamber or into the heat exchanger? If I remember correctly it blows into a section before the actual combustion. But the wall separating the sections has holes to allow the air to pass into the actual ignition chamber. Quote Link to comment Share on other sites More sharing options...
Ulu Posted January 15, 2015 Report Share Posted January 15, 2015 (edited) I'm not an HVAC guy, & I haven't seen that exact heater, but a traditional gas burner will have an air "regulator" door for the combustion inlet, that you adjust manually depending on your air pressure (height above sea level changes this.) My old heater had 3 burners and had one air valve for each. Once you change the jets you have to re-balance the air so the flames are blue and hot. Back in 1974 I got to purge & light the giant 3-conveyor high Pepperidge Farms cake oven. There were like a dozen gas valves at each level & each had an air control at the gas pipe with a short handle and a lock screw. That plant was pretty much state of the art in those days & I had the run of it on the night crew of mechanics & mfg engineers. It was my practical introduction to manufacturing engineering. (EDIT...OH hell! I typed all that & forgot this. Contamination in the gas and gas line can cause backfires. Also, If this heater has a blower for combustion air that's one thing. If the blower is just to purge the heater before lighting that's another. It should stop before the ignition. BTW, The purge routine at Pepperidge Farm involved a 20 HP blower plus flashing lights and a siren. ) Edited January 15, 2015 by Ulu Quote Link to comment Share on other sites More sharing options...
pflaming Posted January 16, 2015 Report Share Posted January 16, 2015 H , m , m, m, ! The last thing I remember, last February, about my 30,000 btu kerosene heater is the 2nd click, at least I think it was a click. Is the 2nd click supposed to be louder than the first? Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.