Heater is Keep Making a Ticking Sound (New GD 23BHE)

[Guest]

I looked up the Suburban RV furnace and their is an anticipator setting at 0.7 on the thermostat behind the cover. An incorrect setting would result in the short burner cycling condition.

It may be worth a look.

Jim

[elranas]

I looked up the Suburban RV furnace and their is an anticipator setting at 0.7 on the thermostat behind the cover. An incorrect setting would result in the short burner cycling condition.

It may be worth a look.

Jim

We bypass the thermostat altogether and it still didn't help.

[elranas]

Propane is measured in inches of water column by using a manometer. 11" of water column is the correct propane measurement. Since this is correct, it eliminates propane as the source.

Elranas. It sounds like you've done a very in depth trouble-shooting. The bench test proved it wasn't an issue with the vents. You've measured the propane. You've replaced the furnace, etc.

I'm totally guessing here. But was the thermostat replaced when you replaced the furnace? It seems like about the only component that hasn't been thoroughly evaluated.

Jim

Yes, we replaced the thermostat and also bypassed it while bench testing.

[elranas]

If both furnaces have been tested on a bench outside the camper and the issue is with both furnaces, air/fuel ratio (propane pressure or line restriction) is the only thing outside of the 12V power feed or the thermostat. A lean condition could raise combustion temperatures. Also for the thermostat, is there an anticipator setting?

Propane static pressure and flow would be two important requirements.

Jim

So someone mentioned that the anticipator setting should be 0.7. I looked at the thermostat and couldn't find it. However, while we bench test it we bypass the thermostat all together.
What do you mean "A lean condition could raise combustion temperatures"?

[Guest]

Any combustion producing device typically is ran at a reasonable air/fuel ratio to produce the cleanest combustion. Lean combustion will result in increased combustion temperatures. Rich combustion will result in soot, black smoke and cooler combustion. A kinked propane line or defective regulator may cause a lean condition. Since you have tested two units(?) outside the rig, and if both failed, the propane feed is all that left.

Also I'm uncertain if you can operate the furnace without the thermostat since the gas valve requires a specific current. This is the purpose of the anticipator function. Looking back I see you replaced the stat at one time.

The anticipator setting should be listed in your manual. In the old days the anticipator setting could be found on the tag on the gas valve.

Here is an example of a heat only stat.

https://www.youtube.com/watch?v=KUavWwSgTu4

Jim

[howson]

Propane is measured in inches of water column by using a manometer. 11" of water column is the correct propane measurement. Since this is correct, it eliminates propane as the source.

Jim,
I did some reading and what I think I understand is the 11" of water column measurement is a static pressure. If the regulator was failing intermittently while propane was flowing, couldn't this cause elranas ' issue? Or am I missing something about the water column measurement?

Howard

[TucsonJim]

Jim,
I did some reading and what I think I understand is the 11" of water column measurement is a static pressure. If the regulator was failing intermittently while propane was flowing, couldn't this cause elranas ' issue? Or am I missing something about the water column measurement?

Howard

Howard. The 11" WC should be measured with propane flowing such as a stove burner.

Jim

[Guest]

These furnaces are design certified for propane/LP gas only. Do not attempt to convert to natural gas.Gas supply pressure for purposes of input adjustment:Minimum - 11” W.C.* Maximum - 13” W.C. *(W.C.* - Water Column). 11 is the minimum pressure.

Copied from an on-line manual.

Testing the gas system:

https://www.youtube.com/watch?v=dK46tDIOzUA

Jim

[howson]

[FONT=sans-serif]https://www.youtube.com/watch?v=dK46tDIOzUA

Good video, Jim. I've never messed with propane or done these tests. I seem to remember TucsonJim recommending a manometer at some point...I'll have to search for that post.

Could the manometer be connected to the lines and monitored while the furnace is running? The manometer seems so sensitive if there is indeed a propane delivery issue somewhere in the piping I'd expect it to reveal itself on the meter. I equate it to monitoring for voltage drops while powering a device.

Based on what I saw in the video: If the tester can be installed with the furnace, what I'd expect to see initially is the "lock up" pressure on the manometer. As the furnace starts and the burner lights the reading should drop to (or near) the 11" mark. It should stay steady while there is flame. When the flame cuts off the value should rise again to the lock up value. What it should not do is waiver or fluctuate while the burner is lit.

elranas -- remember I know very little about propane, so take everything I write in this post as theory--not something to be tried without the input of an expert.

[Country Campers]

elranas

I have the Suburban furnace and have never had the flame start and stop. When the t-stat calls for heat the furnace burns until satisfied , all past RV furnaces performed the same. With the new furnace sent to you did you or the RV tech do a bench test on this? If the new furnace failed the bench test the same as the old one then I would think that there is a batch of bad boards , has happened before. With the state of the manufacture woes across all of the world it is possible that there is some not so good parts being produced. If the new furnace passes the bench test then you will need to check other items as already suggested.

If you have not already done I would bench test the new furnace to rule out a manufacture defects.

Brian

[Guest]

Good video, Jim. I've never messed with propane or done these tests. I seem to remember TucsonJim recommending a manometer at some point...I'll have to search for that post.

Could the manometer be connected to the lines and monitored while the furnace is running? The manometer seems so sensitive if there is indeed a propane delivery issue somewhere in the piping I'd expect it to reveal itself on the meter. I equate it to monitoring for voltage drops while powering a device.

Based on what I saw in the video: If the tester can be installed with the furnace, what I'd expect to see initially is the "lock up" pressure on the manometer. As the furnace starts and the burner lights the reading should drop to (or near) the 11" mark. It should stay steady while there is flame. When the flame cuts off the value should rise again to the lock up value. What it should not do is waiver or fluctuate while the burner is lit.

elranas -- remember I know very little about propane, so take everything I write in this post as theory--not something to be tried without the input of an expert.

Howard,

I have repaired my home furnaces over the years and used a slack tube water and mercury manometer on diesel work long ago, but not to check gas pressure on the home or RV. The video really lays out how to test but who has that tool? Dealer maybe. The lock up pressure is what I refer to as static pressure.

With two furnaces having the same issue this has to be a propane issue.

Jim

[TucsonJim]

It's actually very easy to see if a propane delivery problem is the cause, no manometer is needed. Turn on all the burners on your stove and note their height. Then, turn on the furnace and observe the burners on the stove. if they go down at any time and the furnace recycles, you have a fuel delivery problem. If they stay high and bright while the furnace recycles, it rules out a fuel problem.

If it is a fuel problem, then we can provide trouble-shooting advice to correct it.

Jim

[howson]

It's actually very easy to see if a propane delivery problem is the cause, no manometer is needed. Turn on all the burners on your stove and note their height. Then, turn on the furnace and observe the burners on the stove. if they go down at any time and the furnace recycles, you have a fuel delivery problem. If they stay high and bright while the furnace recycles, it rules out a fuel problem.

If it is a fuel problem, then we can provide trouble-shooting advice to correct it.

Jim

Brilliant, as always, Mr. Hinkle!

elranas -- please give Jim's method a try and report back.

Also--I just got done watching your video about 10 times. What I'm not 100% clear on is the "4.5 minute cycle". Does that reference how long the burner is off or on? If 4.5 minutes is the average time the burner is off, is there a "typical" time for it to be on?

I applaud your persistent pursuit to find what is causing this issue.

[Guest]

elranas

Take your rig to a dealer who can test the gas supply "at the furnace connection" to be sure your at what looks like a 12WC specification. This will cover issues with kinked lines or other supply issues at the furnace.

Jim

[elranas]

This thing is driving me crazy!

I recorded another video bench testing the OLD furnace completely outside the trailer with a separate gas line and a new battery (and bypassing the thermostat) and it worked for 42 minutes straight without the flame going off. I turned it off otherwise it would probably continue indefinitely.

Knowing that it's working as it should have while disconnected completely from the trailer, I went back to the new furnace (the one installed in the RV) and bypassed the electrical in my trailer by connecting the new battery and it failed: flame runs for about 3.5 minutes, off for 1 minute and turns on for another 3.5 and this cycle repeats (fan is on all the time unless system is turned off by the thermostat). I then connected the trailer electrical back and bypassed the propane AND it did the same thing! WHAT?!

For those of you who would think at this point that this is an airflow issue, I have over 400 sq.inch of return (minimum required by AirExcel is 56 sq.inch) and I have all six duct openings utilized so much better than the successful test I did with only two open (see video) AND the old and the new trailer failed the bench test while connected to the trailer electrical and propane.

It is a new RV we bought four months ago. We used it only once and my wife doesn't want to put the kids there until we know it's safe (after all we run this furnace 6 hour during cold nights) - I think she has a point knowing it could be a safety issue. One tech told us that we are abusing the hi-limit switch allowing it to run this way. The hi-limit switch is a safety mechanism not intended to be on and off 12 times an hour and over 70 times over night.

For the past three weeks AirExcel and Grand Design worked diligently to help us find the problem but they are now pretty much telling us that this is normal. I disagree.

Here is the video:
https://www.dropbox.com/s/57kcg20lko...rnace.mov?dl=0