Furnace in our Heartland sounds like a foghorn when lighting

[Mr__Black]

Since new our fifth wheel has been very obnoxious when the furnace lights off. It makes this unusual tuba sound when it first lights. It often wont light off on the first try so you get to hear the tuba sound two or three times. Once lit fully the sound goes away and it sounds like a normal furnace.

This sound is loud enough that I have actually had other people comment on it and has me wondering if we are inadvertently waking neighbors up in the middle of the night.

Trailer is a 2011 Heartland Sundance. Furnace I believe is a Suburban SF-30. I've had this furnace before in other trailers and it never made this noise.

The trailer is at the dealer right now for this and other warranty issues. I am going to pick it up today and I just have a hunch that it's still going to make this noise.

To add insult to injury, my folks also have a 2011 Heartland Big Country and their furnace makes this same god awful noise. Commonality? maybe something in the propane regulator they're using?

Anyone else run into this?

[dougrainer]

Mr. Black wrote:
Hmmmmmm, we may have to use that as ammunition. That being said, pretty sure that the warranty cards were never filled out and turned into their respective manufacturers. For any of the appliances on the rig. 😞 They may or may not get pissy about that.

Not worried about it at this point though as it was documented as being a problem before the 1 year trailer warranty was up.

Warranty cards are NOT required to be filled out and returned for the standard warranty term. They go by your Date of Delivery for the RV. Some appliance makers offer a "free" extended warranty term if they receive the registration card. Splendide used to double the warranty on the Washer/dryers if you filled out the card and returned it to them. I do not think they still do that. Doug

[beaslwd]

Doug, Thanks for the input, on our rig I'll call Suburban tomorrow, and see what they have to say.

[Mr__Black]

Hmmmmmm, we may have to use that as ammunition. That being said, pretty sure that the warranty cards were never filled out and turned into their respective manufacturers. For any of the appliances on the rig. 😞 They may or may not get pissy about that.

Not worried about it at this point though as it was documented as being a problem before the 1 year trailer warranty was up.

[beaslwd]

Mr. Black your furnace has a two year factory warranty, Check the paper work for the furnace itself.

[dougrainer]

I believe the Suburban furnace has a 2 year warranty. Are you still under the 2 years?. Doug

[Mr__Black]

Thanks for the info guys. I pretty much told them it's not coming home making that noise. Especially now that the trailer is out of warranty and that is the last discrepancy technically still under warranty through a paper trail of complaints.

Also a big piece of information that I forgot to post, when we picked the trailer up the first time back when I originally made this thread, we thought it was fixed. They even ran it for us out on the lot before we hooked the truck up to it.

Well, here is what we learned. With the trailer not on shore power and running on a weak battery the furnace works completely normal. Lights off immediately and no fog horn noise. There is a noticeable difference in fan speed running on a partially charged battery. As soon as I got the trailer home that day and plugged it in I knew right away it was going to make the fog horn noise. Sure enough it did. Immediately phoned the dealer back with my displeasure.

That being said, if the battery is fully charged, or the truck is plugged in and running, it will make the fog horn sound as well.

I'll of course keep this thread updated.

[dougrainer]

Mr. Black wrote:
To follow up, the trailer just went back into the dealer today and this time I made them come out and listen to it make this noise in person. I think they finally get it now.

Whether they can do anything about it, remains to be seen.

Here is a short video I took this morning with my phone before we left. Sorry for the filth, she's been sitting all winter outside. 😞 Spring cleaning in the coming weeks. 🙂

https://www.youtube.com/watch?v=Y1smeIipNDM

It NEEDS to be fixed. Suburban will guide them if they have a problem figuring out what is causing it. It is a HEAT LP gas flow problem. You can narrow it down by turning the LP off and the unit will NOT make that noise when no flame. Look at my previous post for the causes of this noise. Doug

[Cuffs054]

Black, I have never heard something like that. I was going to suggest delayed ignition, but I don't think thats it.

[Mr__Black]

To follow up, the trailer just went back into the dealer today and this time I made them come out and listen to it make this noise in person. I think they finally get it now.

Whether they can do anything about it, remains to be seen.

Here is a short video I took this morning with my phone before we left. Sorry for the filth, she's been sitting all winter outside. 😞 Spring cleaning in the coming weeks. 🙂

https://www.youtube.com/watch?v=Y1smeIipNDM

[beaslwd]

Took the outside cover off the furnace this morning so I could get a good look in the air intake tube. clean as a whistle, granted you can not see all the way to the LP orifice. Looks like I'll have to dismantle the furnace next month.

[dougrainer]

beaslwd wrote:
Hey Mr. Black, just spent $50 for a new propane regulator. The furnace still sounds like a fog horn when it tries to light off.

Two blasts to light off and all the boats on the Colorado river pull over, 30 miles away!!

Either the LP orifice has debris in it or the "cone" funnel to the burner is not installed correctly. Sometimes you have to replace the burner when this happens. BUT, It is NOT normal. Doug

[dougrainer]

Mr. Black wrote:
We are not really known for bug related blockages as much in this region. Not saying it's impossible but unlikely. As a matter of fact I have actually found that I get get this furnace to light off immediately if I partially block the furnace exhaust with my hand. It's also unlikely we'd have two trailers doing this same thing at the same time in two different regions.

I have had a few suggest it's a regulator problem but I just don't know. I have asked the dealer to do a LP pressure check with a manometer but I don't even know if they have the equipment for it.

If the issue is not resolved I'll try and get a video of it to capture the sound it makes.

A quick test for a mis-aligned Spark Electrode is the outside hand test. This keeps a larger amount of LP in the chamber that will light. It is also a good test for a restricted LP orifice. This also keeps a large build up of LP and it then ignites. Either way, you have to pull the burner to verify which it is. Doug

[beaslwd]

Hey Mr. Black, just spent $50 for a new propane regulator. The furnace still sounds like a fog horn when it tries to light off.

Two blasts to light off and all the boats on the Colorado river pull over, 30 miles away!!

[Mr__Black]

We are not really known for bug related blockages as much in this region. Not saying it's impossible but unlikely. As a matter of fact I have actually found that I get get this furnace to light off immediately if I partially block the furnace exhaust with my hand. It's also unlikely we'd have two trailers doing this same thing at the same time in two different regions.

I have had a few suggest it's a regulator problem but I just don't know. I have asked the dealer to do a LP pressure check with a manometer but I don't even know if they have the equipment for it.

If the issue is not resolved I'll try and get a video of it to capture the sound it makes.