Journey with Confidence RV GPS App RV Trip Planner RV LIFE Campground Reviews RV Maintenance Take a Speed Test Free 7 Day Trial ×
 

Go Back   Keystone RV Forums > Keystone Tech Forums > Technical Corner
Click Here to Login

Reply
 
Thread Tools Display Modes
 
Old 11-14-2011, 06:52 PM   #1
K&Gs3400RL
Member
 
K&Gs3400RL's Avatar
 
Join Date: Dec 2009
Location: Olympia, Wa.
Posts: 79
Furnace cycling on and off

Took the 5er to the dealer and,The thermostat was replaced Not that day because they could not duplicate the problem. Got it home and same thing was happening, So they sent someone out to replace it. But it is still cycling on and off every 4 to 5 minutes.
Example
On Offf
6:03 6:07
6:10 6:14
6:17 6:22
6:26 6:31
6:34 6:38

__________________

Our New 3400RL 9/17/11

K and G's 3400 RL
2004 Ram 3500
And 5 dogs, Dusty, Sassy, Jasmine, MoJo and Scooter
K&Gs3400RL is offline   Reply With Quote
Old 11-14-2011, 07:13 PM   #2
Ron
Senior Member
 
Ron's Avatar
 
Join Date: Mar 2011
Location: Washington State
Posts: 859
Is it the fan or burner or both cycling on and off?......Ron
__________________
Ron
99 Freightliner FL70 Western Hauler CC 300 HP Cat/Chipped/ Allison Auto
12 Montana 3800RE/Level-Up Auto Leveling/Slide Toppers/MorRyde Hitch/VuQube 2000
01 F350 7.3 PSD Crew Cab DRW 4X4 6 Speed/Chipped


Ron is offline   Reply With Quote
Old 11-14-2011, 08:57 PM   #3
chuck&gail
Senior Member
 
Join Date: Mar 2011
Location: Colorado Mountains
Posts: 422
Make sure none of the vents are blowing directly on the thermostat.

Also might be worth putting a thermometer near thermostat. Is it cold enough that it SHOULD cycle that often?

Do these modern fancy thermometers have an anticipator adjust like the older ones, to adjust temp swing? I don't know, but maybe thermostat mfgr does?
__________________
Chuck
Wonderful Wife
Australian Shepherd
2010 Ford Expedition TV
2010 Outback 230RS Toybox, 5390# UVW, 6800# Loaded
Not yet camped in Hawaii, 2 Canada Provinces, & 2 Territories
I can't be lost because I don't care where this lovely road is going
chuck&gail is offline   Reply With Quote
Old 11-15-2011, 03:44 PM   #4
K&Gs3400RL
Member
 
K&Gs3400RL's Avatar
 
Join Date: Dec 2009
Location: Olympia, Wa.
Posts: 79
Yes the fan comes on then about 30 seconds later the Burner kicks in. Then you can hear the burner shut off followed by the fan.

Two vents close but I dont think either are blowing on it. Doesn't matter on out side temp 32* or 38* it cycles on and off the same the same. Anticipator Mmmm never heard of one, something to read up on tho.
__________________

Our New 3400RL 9/17/11

K and G's 3400 RL
2004 Ram 3500
And 5 dogs, Dusty, Sassy, Jasmine, MoJo and Scooter
K&Gs3400RL is offline   Reply With Quote
Old 11-15-2011, 05:14 PM   #5
Ron
Senior Member
 
Ron's Avatar
 
Join Date: Mar 2011
Location: Washington State
Posts: 859
Are you getting enough air flow through the duct work, possibility not enough flow (collapsed duct) and the high limit swith is shutting it down. Also the sail switch may be malfunctioning when getting warm. Curcuit Board? Good Luck Happy Campin........................Ron
__________________
Ron
99 Freightliner FL70 Western Hauler CC 300 HP Cat/Chipped/ Allison Auto
12 Montana 3800RE/Level-Up Auto Leveling/Slide Toppers/MorRyde Hitch/VuQube 2000
01 F350 7.3 PSD Crew Cab DRW 4X4 6 Speed/Chipped


Ron is offline   Reply With Quote
Old 11-15-2011, 07:21 PM   #6
K&Gs3400RL
Member
 
K&Gs3400RL's Avatar
 
Join Date: Dec 2009
Location: Olympia, Wa.
Posts: 79
Thanks for the info, Between here and the Montana site I have quite a few things to check. I better get busy.
__________________

Our New 3400RL 9/17/11

K and G's 3400 RL
2004 Ram 3500
And 5 dogs, Dusty, Sassy, Jasmine, MoJo and Scooter
K&Gs3400RL is offline   Reply With Quote
Old 11-15-2011, 09:00 PM   #7
Ron
Senior Member
 
Ron's Avatar
 
Join Date: Mar 2011
Location: Washington State
Posts: 859
Good luck, and let us know what you find. Happy Campin................Ron
__________________
Ron
99 Freightliner FL70 Western Hauler CC 300 HP Cat/Chipped/ Allison Auto
12 Montana 3800RE/Level-Up Auto Leveling/Slide Toppers/MorRyde Hitch/VuQube 2000
01 F350 7.3 PSD Crew Cab DRW 4X4 6 Speed/Chipped


Ron is offline   Reply With Quote
Old 11-16-2011, 07:19 AM   #8
hankaye
Senior Member
 
Join Date: Apr 2011
Location: Arrey,
Posts: 2,368
Howdy All;

Checking in late here...
In my older (95) TT I had to swap out the thermostate. The new one was didital found out fast that the temp drop was only 2 degrees. The older Analog thermostat had a temp. differential of 5 or so degrees. So, ...
I got used to a more even temp. but alot more cycles of the furnace....
As the Dealer replaced one and then that one as well .........
I have to ask, was the older thermostate analog or digital???
Also, will the difference between the 2 types effect the furnace's "brain"
(circutboards, chips whatever?)?

hank
__________________
Striving for a less complicated life since 1949 ...

Home: 2008 Cougar 278 RKS
T.V.: 2004 F-250 4X4, Level III BulletProofed , Detroit Tru-Track Differential (915A550)
Dog: 2006 Border Collie (Rascal) aka Maximum fur dispersal unit. (08/04/2006 - 12/16/2017) RIP.
hankaye is offline   Reply With Quote
Old 11-16-2011, 09:14 AM   #9
SteveC7010
Senior Member
 
SteveC7010's Avatar
 
Join Date: Sep 2011
Location: Northville NY in the Adirondacks
Posts: 2,128
I noticed that this is all happening in 30-40 degree temps.

That got me to thinking about the general weather hardiness of RV's compared to a regular house.

* RV walls are probably no better than R-10.
* Ceilings maybe a bit more, but not much.
* Floors probably less.
* Windows are single pane and not 100% air tight.
* Exterior doors are foam filled, but have aluminum frames, and not particularly air tight gasketing.
* Compartment doors probably have very little R factor and their gaskets are not 100% either.
* Roof vents are a single layer of plastic: zero R value.
* There is no insulation in my trailer between the basement and the inside cabinetry of the kitchen. I suspect most are similar.

So what we have here is not the best structure for cold weather. I suspect that heat is dissipating much more quickly than normal and there are likely "cold" spots here and there. If you're using a digital thermostat, the hysterisis program is probably +/- 1 degree on the set point. The Duotherm analog thermostat would be wider, by a degree or two.

The furnace comes on, runs for 4 or 5 minutes and brings the temp back up +1 degree or so above the set point and shuts off. In the three minutes that follow, the warm air in the area of the thermostat cools a degree or two below the set point and the cycle starts again.

RV furnace systems are really designed to take the chill off of a cool day or evening, not provide single source heat in cold weather. There's not enough fan to really move air properly, the ducting is undersized, and the outlets and cold air returns are not at all well placed.

If the thermostat is located on an outside wall or other place where it might cool more rapidly than you might want, consider relocating it or finding a way to insulate that wall. Conduction through the wall may be cooling the thermostat more than ambient air.

If there is a heat duct really close to the thermostat, it may be warming it too quickly forcing a more rapid cycle.

There are a lot of tricks to keeping an RV warm in cold weather. Heat shrink window film on most or all of the windows is a good start. There are commercial insulation things for the 14x14 ceiling vents or you could craft up your own.

That enclosed underbelly and polar package may not be as functional as you hope. I found open flaps on my underbelly and a lot of gaps where air can move in and out.

I have seen people live in RV's up here in northern NY state year 'round. They have to do a lot of inventive things to get through the winters like skirting the entire trailer and then warming the entire under area.
__________________

'11 Cougar 326MKS loaded with mods
'12 Ford F250 SuperCab 6.7 PowerStroke Diesel
Amateur Radio: KD2IAT (146.520) GMRS: WQPG808 (462.675 TPL 141.3)
SteveC7010 is offline   Reply With Quote
Old 11-16-2011, 11:27 AM   #10
campingcpl
Senior Member
 
campingcpl's Avatar
 
Join Date: Nov 2009
Location: Elkhart, Indiana
Posts: 420
My parents had the same problem. They had it back to the dealer and even back to the factory for this problem an after changing out the thermostat a couple of times and replacing the furnace it was still doing it. My dad finally blocked off the vent near the thermostat and relocated the thermostat away from the air flow of the vents and then put a clear cover over it that he can remove to adjust the thermostat. After all that they finally got it to where it doesn't keep cycling on/off. It's still not perfect but better then listening to it turning on and off every few minutes. I replaced our thermostat with a Hunter thermostat that you can get at Wal-Mart and it has made a big difference in how much the furnace runs.
__________________

Phil & Janine & Lady
2004.5 Chevy 2500HD Duramax LLY CC LB 4X4
2009 Keystone Sprinter 272RLS
campingcpl is offline   Reply With Quote
Old 11-17-2011, 09:12 AM   #11
mhs4771
Senior Member
 
mhs4771's Avatar
 
Join Date: Jan 2011
Location: Central Florida
Posts: 478
Check the hole in the wall where the wire for the thermostat comes out. Depending exactly where mounted some have had prolems with heat from the belly traveling up through the wall and hitting the backside of the thermostat. Putting some insulation in the hole and covering with duct tape seemed to do the trick for many with you problem on the MOC forum.
__________________
2011 Chevy Silverado 3500HD Ext Cab LT DRW Duramax/Allison pulling a 2012 SOB (still Thor, but not a Keystone), Dual ACs, 4 Door Fridge, Fireplace, Sleep Number Bed, Level-Up Auto Levelers, Disc Brakes, Winegard DirecTV SlimLine Auto Dish, Onan 5.5K, Splendide Combo Washer/Dryer, GY G114s on HiSpec 17.5 wheels, TrailAir Tri-Glide Pin Box, Mor/ryde IS.

Michelle & Ann Sullivan and 4 American Shorthairs
mhs4771 is offline   Reply With Quote
Old 01-17-2012, 08:12 PM   #12
K&Gs3400RL
Member
 
K&Gs3400RL's Avatar
 
Join Date: Dec 2009
Location: Olympia, Wa.
Posts: 79
Its Fixed
They came out two weeks ago and brought a Brand New Thermostat and control board that are compatible with each other. The first time they just changed the thermostat, and it did not fix the problem. Then they sent out a New control board, that did not fix it either. So after talking to Atwood and Dometic they Ordered a New Thermostat and Control board that they say is compatible. And it is fixed. If anyone needs more info let me know.
__________________

Our New 3400RL 9/17/11

K and G's 3400 RL
2004 Ram 3500
And 5 dogs, Dusty, Sassy, Jasmine, MoJo and Scooter
K&Gs3400RL is offline   Reply With Quote
Old 01-18-2012, 06:46 AM   #13
Johnnyfry
Senior Member
 
Join Date: Nov 2010
Location: Herndon, VA
Posts: 394
Heat cycling

Lots of good suggestions here.

Do you have a digital stat? If so, check to see what the hysteresis (temp drop before calling for heat) is. Mine (Dometic) can be set for either 1 or 2 degrees drop. It will definitely short cycle on the 1 degree setting

All in all, the marginal insulation in these things ("Polar package" notwithstanding!) does cause rapid heat loss when it is cold and windy, so short cycling is to be expected under those conditions.

You might also use a thermometer to check outlet temp at the heat register (or grill or whatever you call it) to see what the temp rise is. You may also have duct leakage in the "basement" area.

John
__________________
2006 Dodge Cummins 3500 Mega cab, dually
2011Cougar 318SAB
Sidewinder hitch
Johnnyfry is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

» Featured Campgrounds

Reviews provided by

Powered by vBadvanced CMPS v3.2.3
Disclaimer:

This website is not affiliated with or endorsed by the Keystone RV Company or any of its affiliates in any way. Keystone RV® is a registered trademark of the Keystone RV Company.


All times are GMT -8. The time now is 08:06 AM.


Powered by vBulletin® Version 3.8.9
Copyright ©2000 - 2024, vBulletin Solutions, Inc.