Suburban furnace

Denn & Carolann · 10-27-2013, 03:55 PM

Has anyone had trouble with their furnace. Ours just stopped working for no reason, plenty of propane, all three burners on the stove will light. no blown fuses, no changes in operating procedures, no blockage of vents inside or outside. This is the beginning of the second season of use. When I raise the temp setting on the thermostat it will operate the fan for exactly 30 seconds and then shutdown. It was working yesterday and today it is not.

Diesel chaser · 10-27-2013, 05:08 PM

Take the thermostat off and jump the heat wires together- if it is wired like a house furnace these should be RED and WHITE - if it runs this way your thermostat is bad. Also could be a bad high limit ( don't know where or if its accessable) Good luck

rcflame · 10-27-2013, 05:51 PM

It could also be the gas valve or the igniter. When the thermostat calls for heat, the fan comes on to clear any combustion air from the combustion chamber, than the gas valve is supposed to open and the igniter spark to ignite the burner. It it doesn't ignite in a certain amount of time, it shuts down. You should be able to remove the outside cover, and check if the igniter is sparking and check the gas valve and make sure it is getting juice If not, it could be problems with the control board. . Also, if you haven't had it running recently, check to make sure your intake and exhaust is clear. Sometimes as little as a spider web can affect the furnace operation. Just some things to check, you may have to end up calling a service person.

Denn & Carolann · 10-27-2013, 07:47 PM

I want to thank you both for your help. I was digging into some of the other rv forums and happened upon a suggestion the was not mentioned anywhere in the repair manuals or even a logical direction that I would consider. On Outbackers.com a suggestion was made... When you trip a breaker while the heater is running you have to shut
down all the power from your 12 volt battery in order to reset the
emergency shut off valve on the heater..........OK...........we did trip a breaker.......I turned the battery disconnect to the off position and waited a few minutes and then turned it back to the on position. Went inside and turned the thermostat up and was surprised when the furnace started to blow out hot air. I am not sure how the 12 volt system is affected by tripping a breaker on the 110 volt side, I thought they were two separate systems, but the furnace is now working again.

Diesel chaser · 10-27-2013, 09:16 PM

Another benefit to our group we all learn from each others problems. Glad to hear you have heat again.

sinder · 10-27-2013, 11:02 PM

I heard about a couple in AZ that had to leave their RV for a couple of weeks and decided to leave the heat on due to cold night-time temperatures. While they were gone their RV Park had a brief power outage and when they returned to their RV the heat never came back on. All of their water lines froze and they had major water damage. I now wonder if their emergency shut-off valve was the culprit.

Dan · 10-27-2013, 11:18 PM

More great information, got to love these forums, lots of good people

almcc · 10-28-2013, 10:34 AM

I've been running the furnace in the Redwood as it's been cool here (with some snow

) and I don't want to winterize as we head south in a week or so. The batteries are completely disconnected from the trailer, I'm plugged into shore power and the 12V power is being supplied by the convertor. I had set the temp at 45 F to keep the pipes warm but to conserve propane. We had a series of short power failures due to the wet snow and when I went into the trailer to check the temp after the power failures the temperature was a toasty 72 F, looks like the thermostat resets itself to this default temperature after a complete power failure.

KR2011 · 10-29-2013, 09:28 AM

Quote:

Originally Posted by almcc

I've been running the furnace in the Redwood as it's been cool here (with some snow

) and I don't want to winterize as we head south in a week or so. The batteries are completely disconnected from the trailer, I'm plugged into shore power and the 12V power is being supplied by the convertor. I had set the temp at 45 F to keep the pipes warm but to conserve propane. We had a series of short power failures due to the wet snow and when I went into the trailer to check the temp after the power failures the temperature was a toasty 72 F, looks like the thermostat resets itself to this default temperature after a complete power failure.

I would put the batteries back in your rig because if the power goes again the furnace will operate as if you were dry camping and keep everything at the temp that you had set it at. If the power goes out for a while you could freeze your pipes. Besides that your convertor is not designed to take that kind of load for very long which will end up in a replacement of the convertor at a hearty price.

almcc · 10-29-2013, 10:30 AM

KR 2011, just for giggles I pulled out the document package received with my trailer and checked the specs on the furnace and on the PD convertor. The Suburban furnace is fused at 20 amps and the PD convertor can produce 100 amps at 13.6 volts. From this data it's clear that the convertor is designed to take much more load than the furnace is drawing. I also understand that some RV manufacturers run the units down the assembly line using the convertor to supply lighting to the trailer without batteries installed.

I do agree that keeping the batteries in the circuit will preserve the set temperature on the thermostat, but I do have a problem with keeping the batteries connected for an extended time when on shore power because of the boost charge from the convertor that comes on every 24 hours or so, and I learned that if you use the battery disconnect switch the batteries will completely discharge over time because the phantom electrical draws that bypass the disconnect switch, freezing and cracking the batteries then becomes a more severe problem.

Edited by: almcc

KR2011 · 10-29-2013, 12:37 PM

Quote:

Originally Posted by almcc

KR 2011, just for giggles I pulled out the document package received with my trailer and checked the specs on the furnace and on the PD convertor. The Suburban furnace is fused at 20 amps and the PD convertor can produce 100 amps at 13.6 volts. From this data it's clear that the convertor is designed to take much more load than the furnace is drawing. I also understand that some RV manufacturers run the units down the assembly line using the convertor to supply lighting to the trailer without batteries installed.

I do agree that keeping the batteries in the circuit will preserve the set temperature on the thermostat, but I do have a problem with keeping the batteries connected for an extended time when on shore power because of the boost charge from the convertor that comes on every 24 hours or so, and I learned that if you use the battery disconnect switch the batteries will completely discharge over time because the phantom electrical draws that bypass the disconnect switch, freezing and cracking the batteries then becomes a more severe problem.

Your correct that the convertor can produce more power than is required from the furnace but is not designed to be the main source of power. Yes there are manufactures that might use the convertor power independently of the batteries. In all of my factory tours I have seen the batteries installed as soon as the 12 volt system is ready to go live.

almcc · 10-29-2013, 02:12 PM

I guess they may install batteries to test, but our dealer receives his units without batteries, the haul guy has to install a temporary battery to bring it to the dealership, the dealer installs batteries as part of the work he does when the trailer is sold.

rcflame · 10-29-2013, 03:33 PM

Depending on brand, the factory either ships the unit with a cheap battery or no battery at all. As for keeping the batteries connected when on shore power, I see no reason to disconnect them. We have kept our batteries connected in our last three campers 24/7/365 without any negative effect. One had 5 years on the original battery's. Just have to top off the water once or twice a year. One big advantage to keeping connected is if we lose shore power, I still have the 12V.

**Dave&Ginny** · 10-29-2013, 07:32 PM

I keep my batteries connected all the time, even in the winter. I start my generator every week throughout the winter and let it run for about an hour. This keeps them charged and a charged battery has less chance of freezing.

**hoosierguy** · 10-31-2013, 12:12 PM

My coach came from the Redwood factory with one cheap (size 24) battery and the dealer added an Interstate (size 24) battery. The coach has been connected to line power virtually 100% (even in storage)of the time since we took ownership in Septermber 2011. I checked the batteries this summer and they were maintaining a full charge. No evidence of any degradation.

I do wish the dealers were a little more proactive about the batteries. I would have preferred two Interstate size 27 batteries, but, that is what I will do when it comes time to replace what I have.

atom ant · 10-31-2013, 12:28 PM

I should have pushed the Dealer better on my batteries, but I had thoughts of 6V. After the first month out with the single 24 causing alarms in the fridge everytime I turned on lights, I surrendered and went with two 27s. The boat appreciated a fresh 24 that it wasn't expecting

.

KenM · 10-31-2013, 01:13 PM

I had our dealer add the 6 volts batteries when we ordered the coach for additional $124.00 including box's. They were installed and ready for our PDI.

almcc · 10-31-2013, 01:15 PM

The reason that I'm disconnecting the batts is that I've had problems with battery life on a previous RV with a PD convertor. I only got around 2 years out of two group 27 Interstates before the capacity went low. We were boondocking overnight with some 12V usage, the batteries were discharged enough in the morning that the electric landing gear wouldn't work without the truck umbilical plugged in. Still don't understand why the PD puts a boost charge into fully charged batts every 24 hours or so when the batt manufacturers call for this procedure much less frequently.

If you are plugged into 120V power all the time you wouldn't notice the loss of battery capacity until you need to use it in a boondocking situation.

rcflame · 10-31-2013, 01:47 PM

I have kept mine plugged in 24/7 except when boondocking. Have spent a week parked on BLM land several times, and with conservation have went the whole week on batteries. If this was a one time incident, maybe it had another cause.

atom ant · 10-31-2013, 03:16 PM

Quote:

Originally Posted by almcc

Still don't understand why the PD puts a boost charge into fully charged batts every 24 hours or so when the batt manufacturers call for this procedure much less frequently.

If you are plugged into 120V power all the time you wouldn't notice the loss of battery capacity until you need to use it in a boondocking situation.

I know you said you had trouble with your last one, but are you sure this one does the same thing?Edited by: atom ant

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