L.P. gas burning in tubes ?? s milne

ScottMP

we had a sevice call yesterday for a no heat.

Turned out to be a defective power venter and a bad elctonic spark module.

My question is whne it was fired back up we got a lot of gas burning in the burner tubes, backing right up to the orifice ?

We did'nt replace the blower, is it possoble even though it appears to have good draft its not pulling at factory specs ?

Could shutting down the unit for three/four hours effect the burning ?

After it ran for about 1/2 an hour it calmed down quite abit.

It also POPS quite loudly on shut down.

I have spoken to the HO about replacing the blower as we could not find one locally on Friday afternoon, and rebuilding the vent ( no screws, non factory termination kit ).

Oh by the way we had 13" WC before the gas valve but could no get the tap out to read on the boiler side.

All three burners tubes we're burning gas in the burner tubes and then little by little settled down but still shut off very rough.

Any ideas ??

Did I forget anything Chris ?

Scott

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B. Tice

Smith Propane

Scott, I have heard of and seen this problem. A plumber I know said that Smith had a remedy for this problem, I think maybe a different gas valve? I've never had a chance to check with Smith about it. But you are right, there is a problem with these units.

Steve Ebels

Does this unit

Have the slotted port type burners? If so, it could be they are dirty/rusty/crudded up. This will cause poor mixing of the air/fuel mix in the burner tube. Sometimes they can be cleaned up by removing them and brushing them off to clean up the slots. Usually though, the slots get out of tolerance (larger than designed) and you wind up replacing the burner set. I see this a lot on that type of burner regardless of what appliance it's on. LP is especially problematic. Doesn't mix as easily as natural does. Personally, I have little use for LP gas. The previous statement is only one reason.

Unknown

LP Gas

Clean the burners make sure they are not damaged.

Part of the problem is the very cold weather we are having which causes LP to react different than normal. Nurse it along before you make big parts changes. Reason is all the part changes will not change the chracteristic of the fuel. This kind of stuff has been going on with LP for years. Just wait it out and see what happens. As long as everything is safe and working it should be okay. Usually once everything gets heated up it will level off.

Find some way to protect the LP tanks from extreme winds and cold without circumventing LP gas safety codes. I have actually put cardboard boxes arounf tanks just to help a little.

Do these burners have air shutters on them? If so adjusting the shutters can help.

You said you did not replace the blower, I assume that is on the Power Venter??? This also could be part of the problem with the burner reaction. Is the power venter working at all? The power venter is going to affect draft, draft is then going to affect air for combustion hence the problem. What happens when it gets heated up HA HA we now have some draft and more air. Draft is created by Temp Difference and height, for lack of height we use a power venter. Hope that makes sense.

ScottMP

Thanks Guys

These units have the cast iron burner tubes. They are very rusty and we brushed them off but I think if we were to clean each port ( round hole ) we would increase the size of the jet.

I would love to know of a repair because my only option here is to replace the whole boiler. Every thing has worn considerably due to lack of maintenance.

Thanks

Scott


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J.C.A.

Thanks guys !

Scott , the only thing you didn't mention is that this bad boy is right on the beach . All the brass fittings and valves are green from the ocean breezes .Thinking about it , I'm wondering if the orifices are out of size due to the salt air .

Timmie , the tank is quite open to the wind and weather . The problem encountered was happenining before we started, and after the burner was shut down for almost 5 hours. I was thinking the same thing about the gas being cold, but as it got warming and running longer , the fire got to where it belonged (on the burner tubes, as opposed to IN the tubes). This puppy was lighting off with a HUGE wump , and the owner thought this was normal ! After effecting all the repairs , it now only "wumps" on shut down of the gas.

Any thoughts you have will be greatly appriciated . You guys are the best !Thanks for the help! Where else can you find folks thinking out other peoples troubles during their own off time ? This is a learning experience for both Scott and myself and I'm glad we have the best minds in the industry to help. Thanks again . Chris.

Boonierat

13\" wc

Mr. Milne:
I'm wondering if the 13" wc of LP you have at the inlet side of the gas valve is just a skosheee bit too high. I normally expect to see a half inch or maybe even as much as a one inch pressure drop across anyone's gas valve. Given that; you may have as much as 12" or even 12.5" wc on the burner tubes. A tad high methinks.
Could be something as simple as too much LP gas pressure literally trying to blast it's way down the tube.
Good luck sir.
Nels

Jeff_8

lp burning back at oriface

I have found that when you have lp burning back to the oriface and/or noise on extinction it is usually too much combustion air. Check your manifold pressure and set it too the manufacturers recommendation, then try cutting the air back so the flame is not sharp. Some yellow tipping can be tollerated. Make sure the venturies are clean of rust and debris.

Herb

ocean exposure ?

This boiler may be in need of some serious TLC. The corrosive nature of the salt air takes its toll on all the parts in the chain of operation. The regulators in the LP stream have their springs and vents exposed also the valves on the boiler and the combustion components must be evaluated. You mention that your cast iron burners were firing at the spuds and detonating on extinction. This indicates that the primary air shutters are open too far. That you noticed alot of rust on the main burners and a failed spark module leads me to think that they may have been opened to far to compensate for reduced draft through the heat exchanger. The boiler should be torn down and the combustion passageways cleaned along a good cleaning of the main burners and pilot. Rework the vent system so you know that its good! To bring the boiler back on line, fire the boiler with the burner shutters nearly closed. They should be quite yellow. Then open them up just enough to remove the yellow (there will be alot of orange color in there from the dust and rust so don't get confused). Do a pressure test on the manifold to verify delivery pressure at the spuds also a pilot extinction test to verify complete closure of the gas valve. Good luck, Herb @ Gibbs Gas Service.