nightwolf20013 Posted October 24, 2017 Report Share Posted October 24, 2017 I have a question. I have a 1998 Fleetwood Bounder with a Suburban furnace SF model. I have fixed the grounding block, taped up the spark unit that's on the circuit board, and cleaned up all of the connections. The thing works great during the day, unless it's cold out, and then I have the same problem, but at night, like every other time it kicks on, it will not light and blow cold. I turn it off and back on and it lights and blows warm. I can't understand why it doesn't work and then works again 2 minutes later. Any ideas? Thanks in advance for your help. Link to comment Share on other sites More sharing options...
Devilishjim Posted October 24, 2017 Report Share Posted October 24, 2017 my guess is circuit board, its not lighting 1st time. It will try 3 times and then you have to reset, So circuit board/igniter/ propane. Try cleaning the tube where propane goes to igniter , a small cobweb can screw things up. Have someone switch it on while you stand at furnace and do a visual can you smell propane/ Is the igniter sparking. Oh and welcome to the forum, You will get more knowledgable people as soon as they wake up Jim Spence 2000 Dodge 3500 1 ton QC 4x4 dually 5.9 diesel LB BD exhaust brake, 6 spd manual trans 34CKTS Cedar Creek 5er, Trail-Air hitch Link to comment Share on other sites More sharing options...
Pat & Pete Posted October 24, 2017 Report Share Posted October 24, 2017 Why would you have to tape anything on the circuit board ? Have you pulled the ignitor out and cleaned the tip and the area where it sparks to ? While in there , bend the tip inward a bit to narrow the gap the spark has to jump . Goes around , comes around . Link to comment Share on other sites More sharing options...
I'mdonewiththis forum Posted October 24, 2017 Report Share Posted October 24, 2017 I agree with Pat & Pete. If there is something that needs tape on the circuit board then there is a problem. That could even be a crack in the ignitor. When I was doing service work there was a brand new furnace in a greenhouse and when it cooled off at night the furnace would run, but at 2AM (or somewhere close) the low temp alarm would go off. I finally found the ignitor had a crack in it. Once it was replaced it ran great. Link to comment Share on other sites More sharing options...
lenp Posted October 24, 2017 Report Share Posted October 24, 2017 Could there be a low voltage issue resulting in the fan not getting enough speed to close the sail switch? After it had ran the fan for a few minutes and you recycled the unit the motor may have warmed enough to run a little faster???? Just a thought. Lenp USN Retired 2002 Winnebago Ultimate Freedom 2012 F150 4x4 2018 Lincoln MKX 2019 HD Ultra Limited Link to comment Share on other sites More sharing options...
nightwolf20013 Posted October 24, 2017 Author Report Share Posted October 24, 2017 Thank you I'll check that out, but not sure why it really only does it at night. Link to comment Share on other sites More sharing options...
Wrknrvr Posted October 25, 2017 Report Share Posted October 25, 2017 Every time there is an ignition problem on a Suburban furnace. You must pull the furnace out and remove all the screws that hold the igniter and the diffuser to the furnace heat exchanger. Then sand all surfaces that mate together and then make sure all screws are tight when you put it back together. Following this procedure will help with making a Suburban furnace operate positively. then you can test all other components. Just my experience,. Vern Link to comment Share on other sites More sharing options...
Wrknrvr Posted October 25, 2017 Report Share Posted October 25, 2017 Now after that statement if the basic things do not make it operate properly there maybe a connection problem on the power source or a control problem. As in loose or poor connects . Safe Travels,. Vern Link to comment Share on other sites More sharing options...
LFDR3116 Posted October 25, 2017 Report Share Posted October 25, 2017 You are aware that when it is cold out, the fan will come on and blow cold air for a minute or two before the burner lights and starts heating the air. At least that's what our Atwood furnace does. Are you waiting long enough for the burner to light? Pat DeJong Link to comment Share on other sites More sharing options...
Kirk W Posted October 25, 2017 Report Share Posted October 25, 2017 11 hours ago, nightwolf20013 said: taped up the spark unit that's on the circuit board, Tell us what you mean by this?Just what did you tape up? PS: Welcome to the Escapee forums! Good travelin !...............KirkFull-time 11+ years...... Now seasonal travelers.Kirk & Pam's Great RV Adventure Link to comment Share on other sites More sharing options...
WILDEBILL308 Posted October 25, 2017 Report Share Posted October 25, 2017 Welcome to the forum. What are you calling a spark unit? Bill 2008 Newmar Mountain Aire model 4521 450 hp Cummins ISM Allison 4000MH tran. Towing a 2014 Honda CRV with a blue Ox tow bar Home base Fort Worth Texas A man who carries a cat by the tail learns something he can learn in no other way. -Mark Twain- Link to comment Share on other sites More sharing options...
nightwolf20013 Posted October 25, 2017 Author Report Share Posted October 25, 2017 The igniter that is on the circuit board, the plastic cover was broke so I used black tape to seal it up thinking water was getting to it. P.S thank you all for the welcome Link to comment Share on other sites More sharing options...
Devilishjim Posted October 25, 2017 Report Share Posted October 25, 2017 The glue in tape is a conductor of electricity if you taped over a connection Jim Spence 2000 Dodge 3500 1 ton QC 4x4 dually 5.9 diesel LB BD exhaust brake, 6 spd manual trans 34CKTS Cedar Creek 5er, Trail-Air hitch Link to comment Share on other sites More sharing options...
nightwolf20013 Posted October 25, 2017 Author Report Share Posted October 25, 2017 I just bought this RV and it looks like someone put a new converter in one of the basement units hooked to two batteries, I have two furnaces on my RV could it be too small of a converter. Link to comment Share on other sites More sharing options...
WILDEBILL308 Posted October 25, 2017 Report Share Posted October 25, 2017 38 minutes ago, nightwolf20013 said: I just bought this RV and it looks like someone put a new converter in one of the basement units hooked to two batteries, I have two furnaces on my RV could it be too small of a converter. You are doing great. The furnaces are 12 V so I doubt the converter is a problem. Bill 2008 Newmar Mountain Aire model 4521 450 hp Cummins ISM Allison 4000MH tran. Towing a 2014 Honda CRV with a blue Ox tow bar Home base Fort Worth Texas A man who carries a cat by the tail learns something he can learn in no other way. -Mark Twain- Link to comment Share on other sites More sharing options...
Kirk W Posted October 25, 2017 Report Share Posted October 25, 2017 9 hours ago, nightwolf20013 said: I have two furnaces on my RV could it be too small of a converter. That is highly unlikely but I'm wondering if you really have two 120v/12v converters? Are you sure that one of them is not an inverter or 12V to 120V? Your furnaces operate on 12V-dc power which can come from either the converter or the battery. It is pretty easy to measure the voltage and a furnace should work reliably on voltages as low as 11V, possibly 10.5v but not much lower. Usually what happens if the voltage falls too low is that the blower will slow down and not provide enough air movement to close the sail switch and so the gas and igniter never turn on. Good travelin !...............KirkFull-time 11+ years...... Now seasonal travelers.Kirk & Pam's Great RV Adventure Link to comment Share on other sites More sharing options...
Daveh Posted October 26, 2017 Report Share Posted October 26, 2017 Why at night only is really an interesting question. Do you have wide temp swings between day and night. Anything else you do differently at night. Do you run propane appliances at night, or shut them off, which may account for the difference? Do you close a vent in another part of the trailer that may account for the difference? Have you tried the gas stove at night when the furnace doesn't want to start? I have a gremlin in my furnace also but it strikes very infrequently. I think my gas valve sticks closed sometimes. Anyway, I like the idea of checking all connections and make a close up and personal inspection. Dave and Lana Hasper Link to comment Share on other sites More sharing options...
Barbaraok Posted October 26, 2017 Report Share Posted October 26, 2017 22 hours ago, LFDR3116 said: You are aware that when it is cold out, the fan will come on and blow cold air for a minute or two before the burner lights and starts heating the air. At least that's what our Atwood furnace does. Are you waiting long enough for the burner to light? This is the first thing that stuck out at me. Often the air will be really cold coming through to the bedrooms at night when it starts up and you need to WAIT for everything to start working. Barb & Dave O'Keeffe 2002 Alpine 36 MDDS (Figment II), 2018 Ford C-Max HYBRID Blog: http://www.barbanddave.net SPK# 90761 FMCA #F337834 Link to comment Share on other sites More sharing options...
nightwolf20013 Posted October 26, 2017 Author Report Share Posted October 26, 2017 Some times it takes me awhile to wakeup and the temp in the house will be in the 50s Link to comment Share on other sites More sharing options...
Kirk W Posted October 26, 2017 Report Share Posted October 26, 2017 11 hours ago, nightwolf20013 said: the temp in the house will be in the 50s Are you then saying that the furnace is already blowing cold air and continues to do so with the inside temperature well below the setting of the thermostat? That does sound as though your furnace failed to light. It would be very interesting to have an accurate reading on your battery voltage when you get up as well since low voltage to the furnace will cause the blower to run but at a lower speed and then the sail switch does not close so there is no lighting of the propane or opening of the valve. Even if the voltage is not falling, that still doesn't mean that the sail switch isn't causing the problem, but does lower that probability. If this only happens at night, we need to figure out what is different at night as that could be the key to determining what the cause is. The way your furnace is wired, the power to the circuit board must pass through the high temp. cut-off, and the sail switch before it reaches the circuit board. Your thermostat sends power through a time delay relay that causes the blower to run for about 30 seconds to purge any combustion gases before the gas valve opens and spark is supplied. The furnace has only 1 motor and it has a blower for combustion air on one end and the blower to distribute warm air on the other so that blower will run as soon as the thermostat calls for heat. If the sail switch is not closed by the blowing air through the heat exchanger, the power will never reach the control circuit board and the furnace just stays in that condition with the blower running and no fire. In later models of Suburban furnace, there is a timer that will shut off the furnace when it fails to start heating but your model does not have that. I suggest that you visit the website of Bryant RV and download a copy of the service manual for your furnace as that may help you to figure out what is happening. Good travelin !...............KirkFull-time 11+ years...... Now seasonal travelers.Kirk & Pam's Great RV Adventure Link to comment Share on other sites More sharing options...
oldjohnt Posted October 26, 2017 Report Share Posted October 26, 2017 Years ago before I was equipped with enough battery energy storage capacity and was parked overnight dry camping in cooler weather, I would go to bed with the furnace working fine, but wake up to it blowing COLDDDDDDDDDDDDD air brrrrrrrrrrrrrrr. The problem was my battery voltage dropped too low for the furnace to ignite even though when the T stat called for heat the blower still began to run as it should to purge the combustion chamber and then ifffffffffffffff ? there was sufficient fan speed and air flow the sail switch closed, the gas valve opened, and the boards HV coil/transformer produced High Voltage which was transmitted to the ignitor tip to initiate combustion BUT THERE WAS INSUFFICIENT BATTERY DC VOLTAGE, the fan still ran but the furnace failed to ignite. Id be checking the battery voltage (12.6 for full charged lead acid) ..............The voltage at the circuit boards input (perhaps at the flat ribbon cable connection)......................When the T stat calls for heat see if the gas valve is opening and if the boards HV coil/transformer is functioning.............. but that doesn't happen unless the sail switch closes upon sufficient fan RPM and air flow PROVIDED THERES ENOUGH BATTERY VOLTAGE?????? On my OLDER units the fan continued to run even if it failed to light but on my later model furnaces if it doesn't light the fan eventually times out and stops. John T Link to comment Share on other sites More sharing options...
nightwolf20013 Posted October 27, 2017 Author Report Share Posted October 27, 2017 Thank you all for your help. I think I got it fixed, it's been working for the last two nights in a row just in time for Kansas winters. I took everything apart cleaned every connector, the connection on the thermal exchanger was pretty bad. P.S. again thank you all Link to comment Share on other sites More sharing options...
Kirk W Posted October 27, 2017 Report Share Posted October 27, 2017 2 minutes ago, nightwolf20013 said: the connection on the thermal exchanger was pretty bad. I'm not sure what you mean by this, but it is good that you have it working. Good travelin !...............KirkFull-time 11+ years...... Now seasonal travelers.Kirk & Pam's Great RV Adventure Link to comment Share on other sites More sharing options...
oldjohnt Posted October 27, 2017 Report Share Posted October 27, 2017 39 minutes ago, nightwolf20013 said: I took everything apart cleaned every connector, the connection on the thermal exchanger was pretty bad CONGRATULATIONS I cant say from here what fixed it or not or if its a permanent fix (only time will tell), but loose corroded or otherwise resistive connections can cause a voltage drop and low voltage (be it connections or the battery source voltage) can indeed prevent it from working. By connection on thermal exchanger you mean the ignitor tip ??? Often an ignitor tip problem can prevent ignition. John T Headed to Marshall TX today then SKP in Livingston Texas. Link to comment Share on other sites More sharing options...
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