Propane puzzle - Heater tries thre times and locks out, WH just "flutters"

Atwood appliances.  All rebuilt within past year.  New regulators.  New flame sensors.  New main regulator.  New temp sensors.  Etc.  Full tanks. Heater and water heater were working last weekend.  This weekend the furnace fires but shuts down; tries three times before lock out.  Water heater fires but flame just flutters (as with low pressure).  Stove works fine.  Checked water column at stove (before regulator) and have 13 with open tank, no appliances; drops to 11 when furnace attempts to fire.  It seems like the problem is low pressure - possibly due to temperature drop in the past week?  And yet, the pressure reading at the lower temperature is correct according to the manuals.  Any suggestions?  Thank you.

  Did you try more than one burner at a time on the stove? I don?t believe it has the safety switches etc like the furnace and hot water heater do. It might light OK, even with lower pressure. Even though it?s fairly new, sounds like a main pressure regulator issue off the top of my head. Maybe some trace moisture or something in the lines that is affecting the regulator now that it?s colder. Maybe try heating the regulator a little as an easy test. Just offering some ideas.

I?m not quite understanding your regulator setup, but any chance you had the propane turned off at the tank and then turned it on recently?  I don?t know if this could cause all the symptoms you described, but if you open the tank valve too quickly, a safety device will limit the propane output.  If that might be the problem, close the tank valve.  I usually relieve the pressure on the line at this point by temporarily turning on a stove valve.  Then reopen the tank valve sloooowly.

Yes, I did have the tanks turned off.  I'll try the warming of the regulator and the opening of the valves slowly.  Yes, all three stove burners work fine but like you said, they operate on a lower pressure.  Yes, it seems like a main regulator problem.  Maybe moisture but it seems repeated lighting attempts would have cleared that by now.  I won't get back to it until Thursday.  I appreciate the suggestions.  I'll do some experimenting.  Thank you.

There's no need to bleed pressure out of the lines, if anything it will exasperate the problem when you turn the tank back on if it's the flow limiting device kicking in.

Basically, it's a ball bearing that gets sucked in and blocks the tank outlet to limit the flow out of the tank in case of a line rupture. Turning the valve on too quickly can trigger it, then you have to turn the valve off and wait for pressure to equalize across the cutoff so the ball bearing can drop back out of the way.

Make sure all of your gas appliances are turned off, then turn off the tank valve(s).  Wait 5 minutes or so for the protection device to reset, then just barely crack the valve open like you would to make a faucet drip.  Wait a few seconds for the system to pressurize, then turn on the valve the rest of the way.

Since all those appliances are rated to run on standard LP gas pressure (11" WC), you don't seem to have a low pressure problem. Indeed, maybe its high pressure (you showed 13" at one point). It's possible you have a flow (volume) problem, though. The water heater and furnace are both high volume consumers. The drop in pressure when the furnace attempts to light seems suspicious to me - it suggests a restriction in the supply line.

A tiny bit of oil (mercaptan from the LP) or water can make a glob that partially plugs a regulator or burner jet.

I will try the slow turn on process; that makes sense.  Low volume since the pressures seems to be correct.  13 inches is the correct reading with nothing on and no less than 11 inches with all appliances running properly but I'll go through that process just to triple check my readings.  Water columns don't lie.  I'll let everyone know if the correct start up process solves the problem.  I likely opened the valves too quickly.  Thank you.

The Fluttering water heater concerns me. We need to find out why. Might just be an air/fuel ratio adjustment or it could be a fuel pressure issue

Where did you measure gas pressure Regulator out or furnace in? Need measure at furnace in

Have you replaced the Furnace CONTROL board?

Is the gas valve opening (if you call for heat from outside, our use the switch/breaker on teh furnace itself,  you may hear a CLICK and/or feel it if you touch the solenoid when power is applied and fan comes up to speed?

I haven't changed the air/fuel mixture on the water heater since it was working properly before last weekend.  I suspect, because both the furnace and water heater stopped working properly, it is upstream at the main regulator.  I measure water column inside at the stove before the stove regulator.  If opening the valves slowly doesn't fix the problem, I'll measure at the furnace in.  No, I have not replaced the control board.

It will now be Friday before I can get back to it.  I'll post the results over the weekend. 

Thank you for the suggestions.

If two appliances start having trouble at the same time, how will changing the control board on one of them fix the problems? Can't be the safeties on the propane bottles, as the stove works correctly. My guess is the propane system is compromised by sludge from the mercaptan in the propane.

kdbgoat said:

Can't be the safeties on the propane bottles, as the stove works correctly.

Click to expand...

The flow protection device doesn't completely block the flow out of the tank, just restricts it to a reasonable level when it trips.

The water heater and furnace each use anywhere from 15000 - 30000 BTU.  A stove burner uses around 6000 BTU and is further buffered by a secondary regulator at the stove inlet.

So it is possible for the stove to work correctly but not have enough propane flow for the other appliances.

Where and when did you fill the tank. Is it possible that you have a propane blend with too much butane in it? Large amounts of butane are often blended with the propane, in warm weather. Butane does not vaporize well (or at all) in cold weather.

Joel

The flow protection device doesn't completely block the flow out of the tank, just restricts it to a reasonable level when it trips.

Click to expand...

"Reasonable" sorta implies it's a useful amount of LP flow, but in my opinion it's so tiny that very few things will work.  I've never tried operating an RV cooktop with the tank excess flow safety activated, but I know my BBQ grill won't even light.

The excess flow cutoff is designed to automatically re-pen after a short delay IF the pressure in the outlet hose stabilizes. There is a bleeder hole that bypasses the cutoff and slowly allows pressure to re-build in the outlet, allowing the cutoff to re-open.  If outlet pressure does not stabilize, the Excess Flow cutoff remains closed and the only gas that gets through is a really tiny amount through the bleeder.

This brief article explains how LP excess flow valves work:
http://www.lp-gasequipment.com/products/pdf/LPGas_Cat2010_p45-51.pdf

OK!  I had two issues.  First, the easy solution was to turn the valves on verrrry slooowly.  I checked the water column for 13, turned on the furnace, and watched the column drop to 11!  Previously it would go down to 3 and the furnace would cycle and lock out.

Next, I checked each of three tanks individually, swapping hoses and checking the pressure and furnace function thinking I had a bad tank valve or clogged hose.  Through the process of elimination, I tracked down a bad Camco 59023 Propane Gauge/Leak Detector.  I had purchased two back in March along with a new master regulator, new hoses, new regulators for appliances, new new sensors, etc.  This one does not allow enough volume through it to run the furnace even though the gauge seems to be accurate (pressure vs. volume). 

I have already filed a warranty claim (1 year).  I'm functional without it but it was nice to be able to see the pressure in both tanks.   

The water heater still "flutters" so I'll have to tear it apart sometime like I did last Spring (air/fuel mix changes makes no difference).  At that time, I replaced the regulator, flame sensor, temp sensors, etc. But, I also found mud dabbers in the burn chamber so I may have something like that again.  I use electric most of the time so I'll wait for warmer weather to tear into it.

So, turn on those tanks slowly and don't believe that new products necessarily work.

Thank you to everyone here for helping me sort through my problem.

Congratulations on tracking down the problem, and thanks for sharing the solution!

I am reading thru all the posts and have my own problem. Thought maybe someone had idea for me, as you all deal with propane... drive thru storm, severe cold, used hookups, furnace and everything fine... left  frigid temps and have been in southern utah. One tank ran out, completely. Got up next am and ran to costco to fill. Everything  worked f8ne. Left hookups and switched to different campground, all "%%$%:^ broke loose. 

We have unhooked, switched tanks, cussed, and not much. We finally turned off, let sit. Tried to light stove top burners, nothing, no gas, turned on furnace, heated up. While it is on burners will light, and h20 heater, and fridge. IF we turn off furnace nothing works....  and wbile furnace is on... burners will work, but evidently you see flame lower and go oit..


Any suggestions....

The "Fluttering" water heater could be either of two things
One is air/fuel adjustment
The other is restricted propane flow.

The Furnace is the LARGEST consumer of propane in terms of quanity per minute and if there is a flow restriction it will be the first to complani

To test the furnace remove the outside panel, if it is an atwood above the blower is a "Switch" (Circuit breaker) turn it off, set T-Stat inside to highest setting and turn on

Process should be
Blower starts. a short time (Seconds) later the gas valve will "CLICK" and it will start sparking, Hopefully it ignights.. IF it fails to sense flame it will shut off and try again, and again and then lock out

Tell us how far it gets in this sequence and we can go from there

Elsewhere (Files and message archives) you will find a more detailed sequence all the way from START to STOP. and potential problems at each step.

Tanglemoose, you should start your own thread as it gets very confusing when 2 people are getting suggestions and reporting back with different results.

keymastr said:

Tanglemoose, you should start your own thread as it gets very confusing when 2 people are getting suggestions and reporting back with different results.

Click to expand...

) ) )

John From Detroit said:

Elsewhere (Files and message archives) you will find a more detailed sequence all the way from START to STOP. and potential problems at each step.

Click to expand...

Sorry to but in here, but where do I find? Looked in Library.