357MDOK furnace not keeping up

[4pmFriday]

Originally Posted by 3532

Hello, new poster here.

we just got a 2021 357mdok after having a 2020 HT30.5mbok.

our new 357 the furnace does not seem to have enough heat.

yesterday 1:00 pm, 30 degrees out. turn heat on to 70. 5:00pm 56 degrees in camper only.

turn elec fireplace on for couple hours, gets to 66 degrees. wake up at 2:00am, down to 57 degrees in camper. turn fireplace on for four hour timer, 64 degrees at 6:30 am. (20 degrees outside, no wind).

furnace seems to cycle the burner, always "warm" air out of the vents, seems like could be more airflow but its not terrible....tried switching propane tank to other and no difference...


i cant find any other complaints online.... any ideas appreciated!

We could not get our main ac fan to stop blowing while the heater was on therefore it was taking the heater a very long time to even get the temperature up 5 degrees. Found out we needed to update the bmpro to get the options to turn off fan on heating cycle. Once we update the bmpro it gave us the option to turn off fan while heater was on. It doesn't turn off the blower fan from the furnace just the over head fan from the ac. Makes all the difference in the world. Reach desired warmth in no time at all. I don't remember the specifics on the update but if go to bmpro website it will give you the details on how to upgrade system.

[3532]

Originally Posted by 4pmFriday

We could not get our main ac fan to stop blowing while the heater was on therefore it was taking the heater a very long time to even get the temperature up 5 degrees. Found out we needed to update the bmpro to get the options to turn off fan on heating cycle. Once we update the bmpro it gave us the option to turn off fan while heater was on. It doesn't turn off the blower fan from the furnace just the over head fan from the ac. Makes all the difference in the world. Reach desired warmth in no time at all. I don't remember the specifics on the update but if go to bmpro website it will give you the details on how to upgrade system.

I did that right away , appreciate the suggestion on it.

[thenne1713]

Is a heat vent perhaps blowing toward the thermostat, shutting heat off too early, or ceiling vents open, allowing heat to escape? History of rodents that would have damaged FLEXDUCT?

Originally Posted by 3532

Hello, new poster here.

we just got a 2021 357mdok after having a 2020 HT30.5mbok.

our new 357 the furnace does not seem to have enough heat.

yesterday 1:00 pm, 30 degrees out. turn heat on to 70. 5:00pm 56 degrees in camper only.

turn elec fireplace on for couple hours, gets to 66 degrees. wake up at 2:00am, down to 57 degrees in camper. turn fireplace on for four hour timer, 64 degrees at 6:30 am. (20 degrees outside, no wind).

furnace seems to cycle the burner, always "warm" air out of the vents, seems like could be more airflow but its not terrible....tried switching propane tank to other and no difference...


i cant find any other complaints online.... any ideas appreciated!

[3532]

Nope the thermostat doesn’t kick out , it shows cold temps And there aren’t even any vents in the hallway where thermostat is.

No rodents. Flex ducts have some extra length that could be hindering airflow some but I haven’t had time to mess with it lately.

[thenne1713]

Originally Posted by 3532

Nope the thermostat doesn’t kick out , it shows cold temps And there aren’t even any vents in the hallway where thermostat is.

No rodents. Flex ducts have some extra length that could be hindering airflow some but I haven’t had time to mess with it lately.

ONE other possibility I can think of: REGULATOR malfunction causing flame too high/ too hot is kicking HI-LIMIT AND (THEN) turning flame OFF via solenoid, (or) spider web/ nest misdirecting flame or causing abnormal flame (with or without potential high-limit switch issues?

[3532]

Originally Posted by thenne1713

ONE other possibility I can think of: REGULATOR malfunction causing flame too high/ too hot is kicking HI-LIMIT AND (THEN) turning flame OFF via solenoid, (or) spider web/ nest misdirecting flame or causing abnormal flame (with or without potential high-limit switch issues?

that is a possibility...i wonder if i can rig up a pressure gauge to just plug into quick connect LP port and watch pressures as things cycle?

[skidoomatt]

Got my camper back home this past saturday from the dealer. Went out this morning and spent a little time listening to the furnace run right outside the intake/exhaust vent as it's too hard to hear inside the camper. What I noticed is that the blower will come on, igniter comes on, burner lights but after about 1:45 minutes or so the burner will shut down while the blower continues to run and cools it down and then the burner will start again and run for another 1:45 minutes before shutting down again. Sounds like it is definately tripping on the high limit switch for some reason. Unit has a build date of 9/2020, I purchased in 1/2021, maybe something got inside the vent and is messing with the burner? Or maybe the excess of flex duct coming off the furnace is causing too much restriction? I'll be sure to keep some electric space heaters in the camper for those cool nights until I can get this figured out.

[3532]

Originally Posted by skidoomatt

Got my camper back home this past saturday from the dealer. Went out this morning and spent a little time listening to the furnace run right outside the intake/exhaust vent as it's too hard to hear inside the camper. What I noticed is that the blower will come on, igniter comes on, burner lights but after about 1:45 minutes or so the burner will shut down while the blower continues to run and cools it down and then the burner will start again and run for another 1:45 minutes before shutting down again. Sounds like it is definately tripping on the high limit switch for some reason. Unit has a build date of 9/2020, I purchased in 1/2021, maybe something got inside the vent and is messing with the burner? Or maybe the excess of flex duct coming off the furnace is causing too much restriction? I'll be sure to keep some electric space heaters in the camper for those cool nights until I can get this figured out.

Mine is the same. Also 9/20 build date. I ran mine yesterday and only needed 10 degrees temp rise and it handled that fine , it’s the 30 degree rise that it won’t handle. I’m trying to figure out where I can run another duct to. I don’t want more in the bunk room which would be really easy to do .... might try get one out to the hallway ?

[skidoomatt]

Originally Posted by 3532

Going to be speaking with a service tech tomorrow and see what they say.

Did you ever speak with a service tech about this? If so, who did you call? Jayco? Dealer?

[3532]

Originally Posted by skidoomatt

Did you ever speak with a service tech about this? If so, who did you call? Jayco? Dealer?

Ya dealer I bought from is 3 hours away, tech said he wasn’t familiar with furnace duct setup of this floor plan... he said he’s never had much furnace issues other than bad batch of high limit switches a couple years ago ... he basically told me to let him know what I figure out ....


local dealer was 3 weeks out for an appt and no help on phone.

Have not tried Jayco themselves.

[skidoomatt]

Originally Posted by 3532

Ya dealer I bought from is 3 hours away, tech said he wasn’t familiar with furnace duct setup of this floor plan... he said he’s never had much furnace issues other than bad batch of high limit switches a couple years ago ... he basically told me to let him know what I figure out ....


local dealer was 3 weeks out for an appt and no help on phone.

Have not tried Jayco themselves.

Gotcha....was just curious was "suggestions" you might have gotten. I expect about the same which is why I haven't called anyone yet.

[thenne1713]

Should be 11-inches water column MAX which is LESS than 1-PSI

[thenne1713]

MOST COMMON problem is wasp/ spider nest in air intake/ exhaust ports from outside, or rodent nest inside inner ductwork? Luck

[JayG7800]

Did either of you figure this out? I'm testing out our 2021 357mdok's furnace today and am equally not impressed. The air out of the vents is warm, but not as hot as our old TT. It doesn't seem to be cycling either, but the warmup is quite slow so far.

[3532]

It hasn’t been cold enough yet this fall. My plan is to run another duct out through the underneath storage and go up into the hallway somewhere. I’d like to go through the bunk room somehow and into living room but I dunno if I can make that work. I truly think the furnace isn’t getting enough air flow.

[JayG7800]

Thanks, I'm a little concerned as it is 55 degrees outside this evening (sitting here in the driveway) and it took a little over 90 minutes to get the temperature up to 66 degrees. At that point, I gave up for the night and went back inside the house.

[3532]

Sounds familiar. I haven’t contacted Jayco but maybe we all need to do that so they resolve our issues ? Seems to be common

[thenne1713]

TIP: Light stovetop, then start furnace and see what effect, if any, on stovetop flame? Suspect should be none. Many LP regulators on recall right now?

[3532]

Each tank on mine has own regulator and furnace acts same on both. High temp cuts burner out when it’s trying to heat up a cold camper.

[skidoomatt]

Just got back from a "fall" camping trip here in Michigan where the evenings got down into the low 50's, so I had a chance to get some use out of my furnace. I can't say my issue has been resolved completely, but it did maintain the unit at the set temp of 65 degrees at night without any issue that I could tell. My burner will still turn on and only run a few minutes at a time, cool off and then repeat....blower fan stays running the entire time. The weekend before the trip I did take some time and removed the excess flex duct coming from the furnace to the main living area floor duct system. This alone helped quite a bit. While I had the ducts removed from the furnace I performed a continuity test on the high limit switch and had continuity at all times during the furnace operation...even when the burner shut off, so I'm not sure if that was conclusive enough to say my high limit switch is ok or not. Still seems odd that the burner kicks on and off so much....nature of the beast? I still need to look into that part a bit. I did have the dealer test the operation over the summer when it was in for some other warranty work and they said it was fine. Not sure I believe them or not. On the other hand, the amount of excess flex duct I removed was shocking....no wonder some of these unit have poor airflow.