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Author Topic: How do I identify this furnace?  (Read 430 times)

1930

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How do I identify this furnace?
« on: November 03, 2018, 04:29:34 PM »
I need to see if it works, if not than I need to make it work. At this point Ive turned the propane on and turned the thermostat up and nothing happens. This is as far as Ive gotten with the exception of pulling off a cover plate.

If I can identify it as far as a model than I can go online and get instructions on how to properly start it up and hopefully diagnose what ails it if it no workie.

Ive looked on stickers and I see no model number.

Thanks for any help with this.

https://postimg.cc/ykv0xBsr

https://postimg.cc/187DY4wG



https://postimg.cc/8sgRntZw

https://postimg.cc/68PRV07r



« Last Edit: November 03, 2018, 04:31:28 PM by 1930 »

1930

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Re: How do I identify this furnace?
« Reply #1 on: November 03, 2018, 04:34:29 PM »
Same with this hot water heater, if I knew a model than I could go online and get clear directions on how to start it assuming it will start.

https://postimg.cc/p5yRBD5j

Isaac-1

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Re: How do I identify this furnace?
« Reply #2 on: November 03, 2018, 04:36:05 PM »
Can you tell us the vintage of the RV that this furnace is installed in? 

The water heater is an Atwood see the label on then right
« Last Edit: November 03, 2018, 04:39:53 PM by Isaac-1 »
2002 Safari Trek 2830

1930

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Re: How do I identify this furnace?
« Reply #3 on: November 03, 2018, 04:51:39 PM »
Can you tell us the vintage of the RV that this furnace is installed in? 

The water heater is an Atwood see the label on then right

Im sorry for that, it is an 88, picture below.

I see now it is in very small print an FA 7920 furnace. Im looking online for start-up procedure but no luck so far

https://postimg.cc/V5XBLfPw
« Last Edit: November 03, 2018, 04:56:39 PM by 1930 »

Isaac-1

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Re: How do I identify this furnace?
« Reply #4 on: November 03, 2018, 04:54:58 PM »
This may be of some help on the water heater http://www.beamalarm.com/Documents/atwood_water_heater_troubleshooting-pilot.html

For the furnace take a look at this it looks similar to your photo Atwood Hydroflame

https://www.youtube.com/watch?v=LIXBMQshKwc
« Last Edit: November 03, 2018, 04:58:45 PM by Isaac-1 »
2002 Safari Trek 2830

Lou Schneider

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Re: How do I identify this furnace?
« Reply #5 on: November 03, 2018, 05:14:32 PM »
If the trailer has been sitting for a while with the propane turned off, you probably have air in the propane lines.  No system is truly gas tight and as the temperatures fluctuate between daytime highs and nighttime lows, the gas in the pipes will expand and contract.  This isn't a problem when the propane is turned on, but when it's off, air seeps in as the gas lines cool off and eventually displaces the propane.

To purge the air out of the lines, make sure everything's turned off and there's propane in the tank.  Get a hand held propane BBQ lighter, you'll need it to light the stove and water heater.  Matches will work, but the BBQ lighter is more convenient.

Turn on the propane valve, and then go inside and use the BBQ lighter to try and light a stove burner. 

You'll probably only get air out at first, but this is a fairly large user so within a few seconds the propane should reach it and the burner will light.

When the flame settles down to a steady blue, the stove has purged the majority of the air out of the lines and you can try the rest of the appliances.  The water heater is next, make sure it actually has water in it's tank and hasn't been drained for the winter.

It will likewise need a flame from a match or the BBQ igniter to light it's pilot, but it's flame is so small you'll sit there all day waiting for the air to exit if you hadn't purged via the stove first.  Even so, it may take several seconds for the pilot to purge the remaining air in it's line.

Turn the knob to Pilot and press and hold it in to bypass the thermocouple, then hold the lighter flame next to the pilot until it lights.  It will take the pilot flame a few seconds after it lights to heat the thermocouple, then you can release the knob and if the pilot stays lit, turn it to ON to light the main flame.

The furnace is auto-ignition, so just make sure the switch on the thermostat is ON and turn up the temperature.  You should hear the fan start, then a few seconds later the flame should start. The flame delay is to let the fan blow any residual propane out of the combustion chamber.  It also may take a few tries (off until the fan stops, then back on) to get the remaining air out of it's line.

You didn't ask, but your refrigerator also has a small flame and may take a few tries to get it to light the first time you use it.
« Last Edit: November 03, 2018, 05:59:46 PM by Lou Schneider »

1930

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Re: How do I identify this furnace?
« Reply #6 on: November 03, 2018, 05:59:14 PM »
If the trailer has been sitting with the propane turned off for a while, you probably have air in the propane lines.  No system is truly gas tight and as the temperatures fluctuate between daytime highs and nighttime lows, the gas in the pipes will expand and contract.  This isn't a problem when the propane is turned on, but when it's off, air seeps in as the gas lines cool off and eventually displaces the propane.

To purge the air out of the lines, make sure everything's turned off and there's propane in the tank.  Get a hand held propane BBQ lighter, you'll need it to light the stove and water heater.  Matches will work, but the BBQ lighter is more convenient.

I bought one of the barbecue lighters already

Quote
Turn on the propane valve, and then go inside and use the BBQ lighter to try and light a stove burner.

Can you explain how to do this? I have not done it yet. Is it just turn the burner dial on and hold the flame near it? Is that it and if so how long should I let it run on for? Id assume if its lit than the lines would be clear right away?

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You'll probably only get air out at first, but this is a fairly large user so within a minute or so the propane should reach it and the burner will light.

Now that the stove has purged the majority of air out of the lines, you can try the rest of the appliances.  Your water heater will likewise need a flame from a match or the BBQ igniter to light it's pilot, but it's flame is so small you'll sit there all day waiting for the air to exit if you hadn't purged via the stove first.  Even so, it may take several seconds for the pilot to purge the air remaining in it's line.

Make sure the water heater is actually full of water and hasn't been drained for the winter if you're in an area that drops below freezing.

Im sorry but I do not know how to check if the water heater has water in it or not, I still have not actually found a water heater bottle per se yet? Where do I find this and how do I check to see if it has water in it?

One other issue I have is that the water pump isnt working. Its making a noise when I turn it on but even after disconnecting the out line no water to be seen. Its is a Shur-Flo 200-210-39.

Not sure what Im gonna do about that yet whether it be replace or attempt rebuild. I'm hoping you wont tell me there is no way of filling the water heater now until I have a good pump hooked up.

I really want to try and get the other things working so i can see whats what.

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Turn the knob to Pilot and press it in to bypass the thermocouple, then hold the lighter flame next to the pilot until it lights.  It will take the pilot flame a few seconds to heat the thermocouple, then you can release the knob and if the pilot stays lit, turn it to ON to light the main flame.

Ive tried pressing in the blue knob and it does not appear to press in or release out?

Also I do not know yet where is the pilot you speak of?

Quote
The furnace is auto-ignition, so just make sure the switch on the thermostat is ON and turn up the temperature.  You should hear the fan starts, then a few seconds later after after any residual propane is blown out of the flame chamber, the flame should start.
It also may take a few tries (off until the fan stops, then back on) to get the remaining air out of it's line.

I will try all of this after I have purged the air but I was told by the last owner that he purged the air already ( via the stove ) and yet still the furnace would not start?

Quote
You didn't ask, but your refrigerator also has a small flame and may take a few tries to get it to light the first time you use it.

I wish the refrigerator were still propane, it has been replaced with an electric.

I wonder if it would be possible and not too costly to get the original style back in there?
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1) Lighting the stove ... make sure the propane is on at the tank (the valve at the top of the tank).  Go inside and hold the BBQ lighter next to one of the stove burners and turn it's knob all the way on.  If the flame lights, propane is there and you're good to go.  If there's air in the line, it may blow out the BBQ lighter so re-light it and hold it a little further away until the flame lights.

If there was air in the lines, the flame may sparkle yellow until the air is purged.  Once the burner has a steady blue flame you're done.  Turn it off and proceed to the next appliance.

2) The water heater tank is integral with the water heater - the flame chimney snakes through it.  I.E., it's directly behind where you saw the blue control knob.  You'll need water pressure to see if there's water in it, if your water pump isn't working connect a garden hose to the City Water Inlet.  To verify the tank has water in it, pull the Overtemp/Overpressure relief valve open (it's on the upper half of the water heater) and see if water comes out.

If no water comes out, there's a pair of valves on the back of the water heater (inside the trailer) that can be set to bypass water around the tank.  Usually one is between the tank's inlet and outlet, maybe a second one is on the tank inlet.  The handle is in line with the pipes for on, crosswise to the pipes for off.  Set them so water flows through the tank, not around it.

The pilot and main burner are inside the flame chamber.  Follow the gas lines into the flame chamber, the small one leads to the pilot flame assembly.  That's where you light the pilot.

3) The water pump ... do you have water in the fresh water tank, or has it also been drained for winter?

4) RV refrigerators start around $1000.  Your choice, but chances are good the gas line, 12 volts and the 120 volt outlet are they're still in place.
« Last Edit: November 03, 2018, 06:32:42 PM by Lou Schneider »

1930

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Re: How do I identify this furnace?
« Reply #7 on: November 04, 2018, 03:28:45 AM »
1) Lighting the stove

Lighting the stove was no problem, Thanks

2) The water heater tank is integral with the water heater - the flame chimney snakes through it.  I.E., it's directly behind where you saw the blue control knob.  You'll need water pressure to see if there's water in it, if your water pump isn't working connect a garden hose to the City Water Inlet.  To verify the tank has water in it, pull the Overtemp/Overpressure relief valve open (it's on the upper half of the water heater) and see if water comes out.

If no water comes out, there's a pair of valves on the back of the water heater (inside the trailer) that can be set to bypass water around the tank.  Usually one is between the tank's inlet and outlet, maybe a second one is on the tank inlet.  The handle is in line with the pipes for on, crosswise to the pipes for off.  Set them so water flows through the tank, not around it.

The pilot and main burner are inside the flame chamber.  Follow the gas lines into the flame chamber, the small one leads to the pilot flame assembly.  That's where you light the pilot.


Ok thanks, Ill check these out and report back

3) The water pump ... do you have water in the fresh water tank, or has it also been drained for winter?

I did check this and plenty of water in tank, I pulled the pump, it is a Shurflo 200-210-39. It is making noise when I finally found the overhead turn on switch that the owners manual for the camper failed to mention ( the owners manual is a joke ) but the noise dosent sound good, Im not sure what its trying to do.

I will prob take a few minutes today to disassemble and see if I can see anything

4) RV refrigerators start around $1000.  Your choice, but chances are good the gas line, 12 volts and the 120 volt outlet are they're still in place.

Im thinking it would be foolish not to have a propane refrigerator, Im guessing the last guy just didnt want to spend any money, Im guessing he bought trailer cheap with hopes of finding someone that just didnt know any better. To an extent he did.

Must be a used refrigerator avail? How can I tell what was originally in there? Id like to get that one or at least one that fills the hole properly.


Furnace is doing nothing when I set temp to high and put the thermostat to on. Nothing at all. The only time it will do anything is when I depress the small button I show in the upper right hand corner of this picture

https://postimg.cc/187DY4wG 

https://postimg.cc/8sGK9h4d

When I push that button, it clicks and I get a humming noise for a few moments and then nothing

1930

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Re: How do I identify this furnace?
« Reply #8 on: November 04, 2018, 03:35:45 AM »
This may be of some help on the water heater http://www.beamalarm.com/Documents/atwood_water_heater_troubleshooting-pilot.html

For the furnace take a look at this it looks similar to your photo Atwood Hydroflame

https://www.youtube.com/watch?v=LIXBMQshKwc

Im sure this will be of help, thanks for posting

Rene T

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Re: How do I identify this furnace?
« Reply #9 on: November 04, 2018, 07:46:47 AM »
Im sure this will be of help, thanks for posting

It would really help us and you if you'd ask one question at a time and post it. We can then elaborate on just that one question. Then create another post when another question comes up. Thanks.

One other thing about the furnace, you'll have to make sure you have 12 Volt DC available. It runs off propane and 12 Volt DC. 
« Last Edit: November 04, 2018, 07:55:21 AM by Rene T »
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Gary RV_Wizard

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Re: How do I identify this furnace?
« Reply #10 on: November 04, 2018, 07:54:43 AM »
Here's a service manual for the Hydroflame FA7920 furnace.  Should help some.

http://bryantrv.com/docs2/docs/hydroflameold2.pdf
Gary
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Gary Brinck
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1930

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Re: How do I identify this furnace?
« Reply #11 on: November 04, 2018, 12:16:47 PM »
It would really help us and you if you'd ask one question at a time and post it. We can then elaborate on just that one question. Then create another post when another question comes up. Thanks.

One other thing about the furnace, you'll have to make sure you have 12 Volt DC available. It runs off propane and 12 Volt DC.
Not too put you on the spot but do you know alot about furnaces/electrical.
 
I am not good with electrical, I do own a voltmeter but am not familiar with its use, Im a smart guy and O know what I know well but this isnt one of them, I have no confidence at this point to know where to begin and how to do it.

I dont want to just throw it out and replace, chances are it is a 50 cent repair, if someone lived locally Id be willing to pay them well just to show me how its fixed/tested.

I need to find someone that says go do this and report back and then go do this and report back and you get the point.

I need detailed instructions, again as long as they have paypal or a mailbox I can pay them.

I want the satisfaction of fixing it myself

Isaac-1

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Re: How do I identify this furnace?
« Reply #12 on: November 04, 2018, 12:39:11 PM »
Well you an always check for the simple stuff, you say nothing happens, is it getting power, is there a blown fuse, ....

You can also manually bypass the thermostat to rule it out by connecting the two control wires together that normally go to the thermostat to make the furnace turn on.

If it does not even try to start up and it is getting power I would suspect a bad control board, there is a company by the name of dinosaur that makes replacement control boards for many RV products, their replacements are often better than the OEM originals and tend to be cheaper, so win, win.  If it is the control board you may want to check to see if they have a replacement.
2002 Safari Trek 2830

1930

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Re: How do I identify this furnace?
« Reply #13 on: November 04, 2018, 12:51:41 PM »
Well you an always check for the simple stuff, you say nothing happens, is it getting power, is there a blown fuse, ....

You can also manually bypass the thermostat to rule it out by connecting the two control wires together that normally go to the thermostat to make the furnace turn on.

If it does not even try to start up and it is getting power I would suspect a bad control board, there is a company by the name of dinosaur that makes replacement control boards for many RV products, their replacements are often better than the OEM originals and tend to be cheaper, so win, win.  If it is the control board you may want to check to see if they have a replacement.

This Quote : You can also manually bypass the thermostat to rule it out by connecting the two control wires together that normally go to the thermostat to make the furnace turn on.

is what I needed. Im gonna go out and try this now, did not know I could do this.

I have a feeling its not the thermostat, I think I hear a click somewhere down there after a few seconds of turning on the heat via the thermostat.

Ill verify that now as well.

B right back, thanks

1930

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Re: How do I identify this furnace?
« Reply #14 on: November 04, 2018, 12:57:51 PM »
Yes a very faint single click after a few seconds of turning the thermostat on ( its set on high heat ) and another faint click after some seconds of turning the thermostat off.

So maybe that rules out a fuse or thermostat?

Whats next?

Isaac-1

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Re: How do I identify this furnace?
« Reply #15 on: November 04, 2018, 12:58:39 PM »
You might also check to see if the fan will freely spin, or if the fan motor is seized up given you heard a click.
2002 Safari Trek 2830

Gary RV_Wizard

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Re: How do I identify this furnace?
« Reply #16 on: November 04, 2018, 02:34:29 PM »
I've written an article on furnace troubleshooting - it's in the RVForum Library at http://www.rvforum.net/miscfiles/Furnace_Trouble-2.pdf

The model for the article is a new Hydroflame, but the basics fr a DSI (spark ignition) furnace haven't changed in 30+ years.  The t-stat signals causes the furnace fan to start, using the furnace 12v source. When the fan gets up to speed, the sail switch closes and the ignition cycle starts, opening the gas valve and trigering the sparker.  Then the controller waits to receive confirmation that the flame has lit (flame sensor). If no confirmation, it shuts off the gas. The fan continues to run for several seconds to clear out fumes, then shuts off.  Since you don't hear the fan start, you are stuck at the very beginning of the process.
Gary
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Gary Brinck
Summers: Black Mountain, NC
Home: Ocala National Forest, FL

1930

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Re: How do I identify this furnace?
« Reply #17 on: November 04, 2018, 02:49:17 PM »
I've written an article on furnace troubleshooting - it's in the RVForum Library at http://www.rvforum.net/miscfiles/Furnace_Trouble-2.pdf

The model for the article is a new Hydroflame, but the basics fr a DSI (spark ignition) furnace haven't changed in 30+ years.  The t-stat signals causes the furnace fan to start, using the furnace 12v source. When the fan gets up to speed, the sail switch closes and the ignition cycle starts, opening the gas valve and trigering the sparker.  Then the controller waits to receive confirmation that the flame has lit (flame sensor). If no confirmation, it shuts off the gas. The fan continues to run for several seconds to clear out fumes, then shuts off.  Since you don't hear the fan start, you are stuck at the very beginning of the process.

Can you explain how yo know its DSI? Please. The guy I bought it from was trying to light it with a lighter and said there was a pilot light.

EDIT: Ok you say in your article that for a pilot light furnace it wouldnt have a control board......mine does as Im assuming you mean the circuit board?

Assuming you have already answered my question.

Thanks
« Last Edit: November 04, 2018, 03:14:37 PM by 1930 »

1930

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Re: How do I identify this furnace?
« Reply #18 on: November 04, 2018, 02:59:54 PM »
Ive printed and am reading your article, thanks for that

1930

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Re: How do I identify this furnace?
« Reply #19 on: November 04, 2018, 03:08:38 PM »
You say

1- The thermostat calls for heat, sending DC current to the furnace.

2- A time delay relay is energized and passes battery DC power to the blower motor

I am thinking and could you confirm that ( please bear in mind at this point propane is turned off outside ) when I turn the thermostat all the way up and then hit the switch underneath ( still on thermostat ) to the on position that the faint single click I hear is the time delay relay?

Im thinking that if I knew where exactly this relay was than I should be able to test it with a voltmeter to see if it is indeed sending power to the fan motor.

What do you think and can you tell me where is this relay with the pictures Ive posted? ( I can post more if needed )

Can you also tell me how to test this relay with my voltmeter as in which post to test and what I should expect to see out of that post.

The click maybe sounds to me like a magnet energized but again its a very faint click.

Im gonna continue reading your article

1930

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Re: How do I identify this furnace?
« Reply #20 on: November 04, 2018, 03:12:03 PM »
You might also check to see if the fan will freely spin, or if the fan motor is seized up given you heard a click.
I thought of this but dont see how to access it at this point without disassembly

https://postimg.cc/QKmm92hq

https://postimg.cc/Wt7cwt45

1930

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Re: How do I identify this furnace?
« Reply #21 on: November 04, 2018, 03:45:51 PM »
Going by your instructions/pictures Ive found the relay I think and Im pretty sure I can feel that faint click I hear. https://postimg.cc/qtvy7178

Now assuming I need to check for voltage leaving going to blower motor I need to figure out which terminal to test. Im assuming I will need the wiring schematic which Im not sure Ill be able to read.

1930

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Re: How do I identify this furnace?
« Reply #22 on: November 04, 2018, 04:37:09 PM »
Ok seems to me that I should be getting power out of the red wire on the top shown in this https://postimg.cc/G489g69g picture and its that wire cause according to this https://postimg.cc/BLgv10wb wiring diagram it is the one going over to the blower motor.

Seem correct?

What should I be seeing on my volt meter when I have the camper plugged into the home outlet via the extension cord and adapter I am using?

Also I know I should know this but can you tell me which setting I should be using on this https://postimg.cc/NK7ZtjyK voltmeter to test this stuff. Im assuming I touch the red lead to the terminal and the black would be OK to touch to the furnace case as a ground?

Im assuming I can test this relay just hanging like this since I see at least one wire going to a ground in the schematic?

If I get nothing out of the relay or not enough than is that a guarantee ( sorta ) that the relay is bad?

If so where might I find a replacement? There must be a specific relay I would need?

If I see what Im assuming I should see coming out of the relay than Im gonna assume its onto the fan motor???

I guess technically at this point I could run a jumper wire from a 12 volt battery onto that red terminal that is supposed to energize motor and see if fans does anything but Im guessing that I could do that and that is all it would take ( and I dont want to assume )  so I will await your reply.

I have to work tomm so cant do anything again till tomm evening.

Thanks for your help
« Last Edit: November 04, 2018, 04:48:48 PM by 1930 »

Gary RV_Wizard

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Re: How do I identify this furnace?
« Reply #23 on: November 05, 2018, 11:04:34 AM »
The label shown in your very first photo says "direct spark ignition".  Frankly I was surprised, since that was fairly new tech in 1988.

In any case, the service manual I linked for you is specific to the FA series and includes the FA 7920.
Gary
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Gary Brinck
Summers: Black Mountain, NC
Home: Ocala National Forest, FL