How do I know if my water heater is full?

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rice40

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I just purchased a 2006 Fleetwood Santa Fe and have only had it out once so far.  I wasn't able to light the water heater, but after doing some reading online it looks like I just need to leave the pilot on for a few minutes before lighting to get the propane flowing.  When reading the directions, it says to make sure the water heater is full before lighting to prevent damage.  If the holding tank is full, is it safe to assume the pump has filled the water heater up or is there some way to check and verify that it's full?  We won't typically be hooked up to a water source but it holds 20 gallons and six more in the heater.  Also, does lighting the water heater also enable the furnace?  I read that the furnace needs both propane and power to operate.  If I'm not connected to electrical hookups, will the furnace draw a lot of power from my 12-volt battery?  Thanks for your responses!
 
Step one,, Check bypass valve(s) if they are set for use then go to step 2,  if they are not set for use do so

Single and dual valve systems the valve(s) must be in the USE position,  IF not marked then it is the position where the handle points TOWARD the water heater

3 Valve systems.. normally the valve handle is an oval.. The top and bottom (or right and left) of the 3 valves th major axis (lone one) should parallel the tubing.. the cross over (Bypass) line sould have the minor axis parallel (short one) in short the valve should appear to CROSS the tube.. like this =====|======

Now, Step 2

Open any hot water faucet for one full minute.. If it flows, then sputters, then vents air, leave it open till water again flows

if after one mintue it is still gushing water,  Water heater is full.  Or rather.. Properly full enough.  (you do not want it entirely full,, Just full enough).
 
Make sure the heater winterizing bypass valves (if any) are positioned to let water into the heater tank. Then connect hose to trailer water inlet or fill fresh tank and turn on pump. Either method will cause the heater tank to begin to fill, but you need to open a hot water faucet in the RV to let the air escape, or open the Pressure/Temperature Relief (PTR) valve on the tank. When water comes out of the tap or PTR instead of air, the tank has adequate water for use. Close the PTR as soon as water appears there. Then you can light the burner. If you have been using other LP appliances (stove or furnace) there will already be LP in the gas lines and the pilot and burner should start right up. If not, be prepared to fiddle a bit to get the pilot to light. The main burner lighting is controlled via the heater thermostat, so will proably attempt to light right away. If it doesn't light at first, give it a minute and try again.

The furnace  is not connected to the water heater or its pilot. It probably has its own pilot, or maybe even direct spark ignition (DSI) and lights itself when the thermostat calls for heat. If you can identify the furnace make  & model, we can tell which it is. The furnace gulps propane and its fan sucks battery amps as well. How much of both depends on the furnace size, but yes it will run the battery down faster than most anything else in the trailer.

Water heater and furnace operator manuals are usually available online for download. Identify the make & model of each and we can help you find them.
 
Thanks, both of your responses were incredibly helpful!  I opened the relief valve and water came out so that seems like a good sign.  The heater is a Suburban SW6P which I don't think has a bypass valve, but maybe someone can verify that for me.  The furnace is an Atwood Hydroflame.  Sounds like all I need to do here is turn the propane on and set the thermostat?  Will using the furnace overnight completely run down an 85 amp hour battery?  Will it operate off of 110 if we have hookups?  Doesn't seem practical to have to run the generator half way through the night to keep the battery charged.  Thanks again!
 
rice40 said:
Thanks, both of your responses were incredibly helpful!  I opened the relief valve and water came out so that seems like a good sign.  The heater is a Suburban SW6P which I don't think has a bypass valve, but maybe someone can verify that for me.  The furnace is an Atwood Hydroflame.  Sounds like all I need to do here is turn the propane on and set the thermostat?  Will using the furnace overnight completely run down an 85 amp hour battery?  Will it operate off of 110 if we have hookups?  Doesn't seem practical to have to run the generator half way through the night to keep the battery charged.  Thanks again!

The bypass valves are not part of the water heater. It's something that the RV Manufacturer installs after the water heater is in place.
 
rice40 said:
Rene T, where would I find this and what does it look like?

The valve or valves would be on the inlet and possibly the outlet of your water heater on the back side. There are basically 3 different configurations.  Here are some of the different configurations: 
https://www.google.com/#q=rv+water+heater+bypass+valve+diagram&revid=164765011
 
Suggest you either turn on the water pump or be hooked up to the parks water supply, then open the hot water faucet at the sink and let it run until you get a steady stream.  Then light the water heater.

If you look in your manual one of the safety warning will state that not using the water heater for a couple of weeks can allow hydrogen gas to be created inside the tank.

Kinda wondered why there was an oder every once and awhile.

Haven't ever heard of an RV turning into the Hindenburg but......heard of bad water smells from water sitting in a water tank...

WildBill
 
The Santa Fe is a smallish pop-up trailer. Not sure how automatic any of its systems are - most pop-ups are fairly basic in those components..

Sounds like all I need to do here is turn the propane on and set the thermostat? 
I suspect you have to light a pilot for the furnace, but once it is lit the thermostat controls the on/off cycles.  Hydroflame is Atwoods furnace name. Would have to know the model, e.g. 8516, to get into more detail. Does the Santa Fe actually have a wall thermostat? Or just a dial on the face of the furnace somewhere.?


Will using the furnace overnight completely run down an 85 amp hour battery?
If it actually runs all night, yes. Whenever the furnace fan is running, it probably draws 4-6 amps. 8 or so hours of that will pretty much deplete an 85 AH battery. But when the fan is off (furnace on standby), it uses almost zero power.


Will it operate off of 110 if we have hookups?
When plugged in, a small converter produces 12v power so that the battery does not get run down.
 
Thanks for all the tips!  My manual says it is for the 7900, 8012, 8500, and 8900.  Can't tell which one because I can't access the inside of my trailer while it's in my garage.  However the manual says "this appliance is equipped with an ignition device which automatically lights the burner.  Do not try to light the burner by hand".  That's why I'm assuming I just need to adjust the thermostat and the furnace will do the rest.  Hope I'm right.
 
You are!!! The fun starts when it refuses to light, but that is another story for another time!!
 
My manual says it is for the 7900, 8012, 8500, and 8900.

Well, those are every model of furnace that Atwood makes, so there will be some small differences depending on the model. Pop-ups typically have the 7900 series of furnace, so that's what I'm guessing.  Some of them have an On/Off switch that has to be on for the furnace to work at all, but many owners just leave it on 24/7 and use the thermostat for full control. Yours is a recent enough model so there is no pilot, so that makes life easier. DSI spark ignition works very nicely and is mostly trouble-free.

So yes, assuming the switch is on the thermostat will handle it for you.
 
So glad I found this forum... you guys are very helpful!  Thanks!  One more question.  I need to buy a new extension cord.  Is there any reason why I need to buy an expensive 30 amp rv cord or can I just buy a standard 50 ft extension cord to work with the 30amp adapter I already have?  Will a medium duty 14 gauge cable rated for 15 amps be enough?  The most I'd ever run simultaneously would be the fridge, a/c, and water pump.
 
rice40 said:
So glad I found this forum... you guys are very helpful!  Thanks!  One more question.  I need to buy a new extension cord.  Is there any reason why I need to buy an expensive 30 amp rv cord or can I just buy a standard 50 ft extension cord to work with the 30amp adapter I already have?  Will a medium duty 14 gauge cable rated for 15 amps be enough?  The most I'd ever run simultaneously would be the fridge, a/c, and water pump.

If you're going to run the A/C, you should have a 30 Amp cord.  You'll also have a converter running al the time charging the battery and providing 12 volt lights.
 

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