Loud, big , yellow flames. Burning in tube?

gyrfalcon

Video link attached https://youtu.be/pn0unl_xOzQ?si=PVsipbNUsm6Cc-Dy
Blue flame in burners.  Yellow flame outside of burner 
 This has happened 2 times in 24 hrs.  I can kill power and cycle back on and flames are then normal.  No other gas LP appliances are acting up.  This gas valve was replaced earlier in the season because gas would not flow through pilot on old valve.   Any thoughts? 

Jamie Hall

First guess. Regulator is sticking. That needs service soonest.

EBEBRATT-Ed

Sometimes propane tanks get a little water or condensation in them . LP gas acts as a refrigerant when it vaporizes and can cause sticking regulators if it freezes. Contact your propane company and have the gas pressures and regulators checked

gyrfalcon

@Jamie Hall
as in the regulators outside the house?  There are 2- one one the lp tank and one at entry of house. My Richmond direct fired water heater and Chambers cook stove exhibit no signs of malfunction.   

WMno57

gyrfalcon said:

My Richmond direct fired water heater and Chambers cook stove exhibit no signs of malfunction.   

The WH and stove may be better able to deal with an increase in pressure from the LP tank. Trouble shooting 101. Don't make assumptions, gather data (wouldn't be too hard to get an actual pressure measurement with the right tool).

HVACNUT

The LP conversion kit wasn't installed in the gas valve or the manifold pressure is too high. Should be 10".
Is there a yellow sticker on the gas valve showing it was converted?

gyrfalcon

The gas valve gas the LP sticker on it.  Flames are normal size and color right now.  Im thinking the wet and near freezing conditions outside may be a factor. Further investigation needed. 

HVACNUT

What's lockup and manifold pressures while no other LP appliances are on, then with all other LP appliances on?
What's the draft at the breach?

gyrfalcon

I don’t have gas measurement tools.  I’ll call in a service tech and likely LP provider to see what’s up. 

gyrfalcon

A service tech came earlier in the week.  Said boiler gas valve is at 10.5 wc and gas regulator at the house is 13.8 and maximum should be 14? 

He thinks the main regulator on the tank is bad perhaps.  The LP supplier is coming out today.   The issue has not been observed to be happening again. We shall see. 

gyrfalcon

On a side note- I’ve been interviewing a few other contractors for new installation when the time comes.  Company A said he will do heat loss calculation and measured emitters . Company B said don’t ever replace your boiler unless it’s no longer repairable but I’ll give quotes anyway.  Company B said any smaller boiler is bad because it will run for longer cycles and in doing so will erode the copper pipes.  No measuring whatsoever from B.  His quote showed up a few hours later for a 80k btu Crown cast and an unspecified Rinnai combination unit.  Still waiting on quotes from A. 

Company A also taking into consideration the fact that my wood stove flue,  Tree leaves and pollen all may affect the intake air of a high efficiency boiler. 

WMno57

gyrfalcon said:

Company B said don’t ever replace your boiler unless it’s no longer repairable

That might be good advice.

gyrfalcon said:

Company B said any smaller boiler is bad because it will run for longer cycles and in doing so will erode the copper pipes.

OK, that is one of the more bizarre excuses for being lazy and not taking the minimal amount of time to correctly size equipment. Get a pallet of distilled water from Walmart, add the correct amount of a Corrosion Inhibitor, done. And spec the right circulator that will circulate the water at the proper speed.
As a fellow Hoosier, I'd like to point out to the East Coasters, this is an example of hydronics expertise out here in fly-over country. This is why I DIY.

gyrfalcon

LP company checked outdoor regulator pressures at full load and lock up. Made adjustments to bring outdoor pressure to spec.  We will see what happens 

gyrfalcon

It happened again this morning.  I tried turning the gas shut off to nearly closed . Flames got smaller but still discolored and burning in the tubes.  I then switched the  power off and then back on. Flames are now blue and normal.  

After the lp provider made their pressure adjustments I added a little hood over the gas valve at the house. This was made out of an old plastic flower pot drip pan.  Just to keep rain and snow off the valve.  Does not obstruct or block airflow or vent at all.  

What are the odds that a gas regulator valve is still malfunctioning?
 Could the gas valve on the boiler be bad? 

This is one of those rare and hard to replicate issues for  anyone to perform diagnostic testing. 

gyrfalcon

Upon further reading, this appears to be a somewhat of a common problem with LP in cold weather.   

SteamingatMohawk

There have been discussions in the past few years about the air quality going to the burners. Two specific situations come to mind.

In one case a poster had to move a litter box because of the "fumes" from it.

In my case, I found that if I kneel down to examine the flames, they may turn yellow. If I stay still for a few minutes the yellow decreases. My 100 year old basement has dust, etc. that gets stirred up and sucked into the fire box.

EBEBRATT-Ed

All gas flame turn yellow when you move around and disturb the dust. I would remove and clean all the burners and re install and make sure they are aligned properly.

Maybe install some gas pressure gauges temporary so you can see what the pressures are when it is running normally and then check them when it acts up.

gyrfalcon

Since we have had fairly mild weater(low 30s to high 40s ) the flame issue has not happened again.  I’m thinking that it’s a propane temp/ intermittent regulator problem.   

EBEBRATT-Ed

Certainly possible