Propane Crown boiler flame issue

hankwylerjr

I have an old crown made by Dunkirk AFB 175 LP. We changed out the thermo couple, spill switch, replaced the vent pipe sealed and taped everything. We installed new connections on the wires. We cleaned the burners very good which are SS but old . We replaced the pilot and assembly. The tank is at 30-37 percent full. We checked for leaks tightened everything possible. Fires up but the flame is blue but with more orange then Id like. Wondering if it's because of low propane or something else had our HVAC guy adjust the gas valve accordingly the heat was coming up within the 4 zones very nice. Could soot be the culprit? Any idea why the flame is not solid blue? No gas leaks space is fairly large so plenty of oxygen. Thx in advance

pedmec

you need a manometer to check both up stream and down stream pressure of gas at the gas valve and a combustion analyzer to check for proper combustion. That should give you an idea of why your flame is yellow. You might be a little lean with oxygen but you need the proper tools. anything less is just a guess.

EdTheHeaterMan

I have a question about one of the things that you said. 

replaced the vent pipe sealed and taped everything.

I hope you are not referring to tape of any kind on the vent connector. I believe the only way to secure the vent connector joints on a Category I appliance is with sheet metal screws. Vent connector is often called smoke pipe. 

I think I read somewhere that tape of any kind is not to be used to secure the vent connector on a category I appliance. That vent connector should be at less than atmospheric pressure. That means the any leaks will leak into the smoke pipe. Fumes won’t leak out.  If byproducts of combustion are leaking out of the vent connector, then you have a different problem to solve 

hankwylerjr

thank you yes our tech used his instruments he said everything was within normal limits, I’ll double check I have to do something else there I’m sure I can google the specific reading limits for the manometer but any help again is appreciated we used Aluminum Foil Duct Tape Heavy Duty on the smoke pipe and used furnace cement to seal it sorry 

Jamie Hall

Colour. Is the flame orange? Or is it yelloo? It makes a huge difference. Orange is very often from dust in the air or small amounts of salt. Very small amounts. Yellow indicates perhaps the air/fuel mixture is slightly off.

hankwylerjr

@Jamie Hall long time no talk.... hope all is well. The color is orange not yellow. We swept the floor quite a bit after install and the tank of propane is at about 35 or so when its supposed to be over 80 per customer

bburd

The orange flame is very likely from dust stirred up while sweeping. It will probably settle down. I have seen this effect even from disturbing the air while moving into position to look at the flame.