Hydroflame Incident

[Stefrobrts]

We were away on an overnighter with the Caravel last night, and needed to use the heater for the first time in months. I lit the stove first to get the propane in the lines, and then lit the pilot on the Hydroflame furnace. It took forever to get it to stay lit. Once it did the main burner came on, but went out after about a minute. I turned up the thermostat from 2 to about 4, hoping to make the burner come back on, but nothing happened. A few seconds later there was a small explosion a loud bang and flames shot out the access hole where you light the pilot from! After that there was no pilot light, no gas smell. Scared the heck out of me! So we skipped the heater and just threw on extra blankets.

But what happened? I don't understand how gas could have accumulated to cause the explosion, as the pilot was lit the whole time. At no time did I smell propane outside the furnace, and the LP detector is right next to it and didn't go off, so all the propane was contained within the furnace cylinder. Could this have been a case of a valve failing and letting a large amount of propane into the cylinder at once?

Needless to say I was shook up enough I didn't attempt to re-light it. I want to make sure nothing was damaged before I do. I'm afraid the RV shop I go to is just going to shake their head at me if I ask them to look it over, they're not very fond of my vintage appliances already. Any suggestions?

[3Ms75Argosy]

Steph,
Is there a cover to go over the pilot hole? Here's my theory (but honestly, best guess). The sail switch didn't heat up enough to keep the flame on, and then shut off the main burner, BUT, started leaking. I'm assuming that the thermostat just controlls when the flame goes on, NOT the amount of gas that enters the burner. With the cover off, (maybe your front door was open too?) a small enough draft kept the main burner "leak" away from the pilot light, until the gas accumalated enough to ignite and "explode." The reason I mention the cover is that on my newer unit, I have to close the cover so that there is not a draft.

My worry for you is two-fold. Is the sail switch (if your unit even has one) is defective - there shouldn't be gas flowing if the main burner is off, and with the explosion, if it ruptured your combustion chamber, now allowing CO to escape if you use it again.
Maybe a call to Andy would help?
Marc

[Stefrobrts]

It has a cover over the access hole, but it was open because I was watching to see if the burner was coming back on or if the pilot had gone out.

I am also concerned about the chamber not being completely sealed now because of the explosion, however everything looks ok visually. I also have a CO detector mounted on the ceiling above the furnace, so if there's a leakage problem it should go off. I'm more concerned about the possiblity of a failed valve. What is the sail valve? I'm familiar with the thermocouple opening a safety valve, is the sail valve another part?

[3Ms75Argosy]

Steph, I believe they are the same thing, different name. My understanding is that it stops the flow of gas when the flame is not lit. Anybody chime in if I'm wrong.
Marc

[thenewkid64]

The sail switch is a micro switch that has a little arm with a square of metal. This square of metal is in the output airflow from the furnace to the duct work. If the blower is not running at a high enough RPM to push the sail and close the switch the gas solenoid will lose power and close, shutting off the gas.


With all that being said, I don't think there is a sail switch in a hydro flame furnace. Or one with a standing pilot. Normally they are in the newer electronic ignition models, but I could be wrong.

The flame out you describe is likely due to the fact that the cap was off the pilot hole. On the furnaces I had with a standing pilot the cap had a semi clear window so you could see the pilot was lit. What I surmise happened was that the pilot was lit, the thermocouple got to temp, and the main burner was attempting to light. The fact that the pilot hole was open added additional air to the combustion process and caused it to blow itself out.

Since you have all the detectors, you could light the furnace and leave the trailer for an hour and see if the detectors alert. This would tell you if you have a CO leak, and if you set the thermostat low enough you should get two or three on/off cycles.

BUT If you are uncomfortable with this, take it to the dealer and have them check the furnace. Safety comes first!

[Stefrobrts]

Thanks, Brett. You're correct that the Hydroflame has nothing so fancy as sail switches and fans as described. I would barely call it a furnace. Craig Dorsey called it a 'smudge pot' It has a thermocouple/safety valve for the pilot light, and a small burner in the combustion cylinder that is smilar to a stove burner. Very simple construction.

My access hole cover is not clear, but I wish it was, it would be easier to tell if the pilot has blown out. Thanks for the advice. I'll see about lighting it again and if it doesn't go smoothly I'll talk to the RV shop about it. Maybe having the access hole open was the cause of my problems.

[Stefrobrts]

An update on the Hydroflame. I haven't messed with it since the flame-out incident. We're heading for the mini-rally this weekend, so I thought I'd give it a shot and light it and see how it was. Well, I had no problem lighting the stove first, as usual, to get propane in the lines. But when I went to light the Hydroflame's pilot light, I got nothing. No propane going through as far as I can tell. It won't light, and I can't smell propane. So I think something must have gotten damaged.

I have an electric heater in the trailer now, so I guess that's what we'll be using for the rally this weekend. Luckily we have electric hookups.

[garry]

The problem I had was the pilot light deflector somehow stopped deflecting the pilot light flame over the burrner tube so a few seconds would go by with out lighting the burner gas and BOOM....Fix was to bend the pilot deflector back down so the flame was over the burner.(This was not a Hydroflame furnance).
Another thing you might look for is the burner holes closest to the pilot flame are stopped up with rust and need to be cleaned with a vacume. This would cause the burnner holes furthest from the pilot to let out gas and build up until the pilot flame ignites the gas and "BOOM".

Garry

[Stefrobrts]

Thanks, Garry, I think I'll be taking it apart and cleaning it up, and then taking it to our RV shop to see if they can figure out the details of what's not working. I sure missed it this past weekend. It does a much better job of warming up the trailer than the little electric heater did!

[micabarry]

Stephanie, I am new to this forum but saw your issue and also have a furnace problem in my 66 Caravel. I have model RN9 which I took out and took to a gas shop for repair. My problem was a gas valve which is $170 for the part and probably $40 for labor. I'm currently seraching out replacement furnaces but depth is a problem because of the wheel well. May be able to mount one of the Wave heaters in the space. Have you had any luck? I may have parts on mine if I decide not to fix it. Barry

[Stefrobrts]

Hi Barry, welcome to the forum! There are lots of Caravel owners here!

I haven't looked into it further yet. I see there is one on eBay right now that I might buy for parts if it isn't too expensive. It looks like it is in very nice shape.

I would be happy with a $200 repair. Furnaces can be quite expensive, and I'm not sure I like the catalytic heaters. We had one in a Bambi we had for a short time this summer, and it certainly did heat up the area quickly, but I wasn't comfortable with how exposed the element was. I think Rich ("rluhr" or "Airstream Life" are his names on this forum) has one in his Caravel.

The Hydroflame heater that came in the Caravel works well, and seems very safe to me. I think it's worth fixing up. Another thing I found out by visiting some newer airstreams is that the new furnaces have things like built in blowers which always run when the heater is on, and can be very loud in a small trailer. They also have electronics that drain the battery while boondocking. And I just don't think you will find any of them that will fit in the tiny space provided.

Let me know how you decide to go. I am currently looking into a little floor rot problem, then I'll be tackling the heater problem again.

[Stefrobrts]

I took the Hydroflame in to the RV Shop that I use in town. The owner is always eager to help, but his appliance guy is not so eager to work on my 'vintage' stuff. So he called this morning to tell me it would take two hours of work to clean up the old furnace before he could even start troubleshooting on it! That's $88 an hour! So my husband said no-way, because if the guy determined it couldn't be fixed, we'd be halfway to paying for a new one and then get the word it couldn't be fixed.

Landyachtdoc (Darol) in Ridgfield has installed a modern heater in a Caravel that belongs to one of our unit members. So I emailed him, Tony, and asked him about his heater. Here's his response:

The furnace Darol installed was an Atwood hydro flame #7912-II with a big 9,160 BTU/HR output. It is 8 3/8" W, 11 3/8" H and 20 5/8" D. It fit right in with Darol's expert installation! The fire box in the original heater rusted out.

It works just dandy, keeping us warm when the snow fell. We especially liked the thermostat Darol installed over the bed! No controls to fiddle with except on/off and temperature, both at the thermostat. When the desired temperature is set, the furnace goes on and off automatically. We also like the nearly flush to the skin exterior heater vent.

So there is a modern option that will fit in the space. It fits in the top right corner of the hole the old heater filled, so it just clears the wheelwell. I guess it's our only option. It would be nice to have a thermostat and be able to just turn it on without getting on my hands and knees with a lighter.

So my question to you guys is - how quickly will a heater like this run out the battery if we're boondocking? Last year we spent four or five days in the mountains with no hookups at the astronomy party. Will we ever be able to get away with that again once we have one of these new-fangled furnaces?

[malconium]

Stephanie,

Someone in the forums pointed to some alternative heaters that do not use any electricity. The following website is for the company that makes them and has descriptions of the products:

http://www.uscatalytic.com/heater_index.html

They are available for purchase at the RV Parts Outlet near us in Tualitin, Oregon or by ordering them. Here is the RV Parts Outet store web site and one other web site that I found that carries the units:

https://www.rvpartsoutlet.com/newstore/nojava/index.cfm (look under heaters in the general index)
http://www.rvstuffusa.com/heatingac.html

The second site listed above does show some other heater options that might work. They carry what looks like the Atwood line you mentioned that Daryl used except that the models shown seem to be 12,000 to 19,500 BTU's. I also found the Atwood website but they do not seem to list the electrical part of their specs there.

http://www.atwoodmobile.com/Products/furnace/7900.cfm

They did mention that this particular line of heaters was used for Everest expeditions and etc. It couldn't use all the much electricity just to run a fan. Pehaps you can email them and ask about that?

Malcolm

[srrobertsiii]

Originally Posted by micabarry

Stephanie, I am new to this forum but saw your issue and also have a furnace problem in my 66 Caravel. I have model RN9 which I took out and took to a gas shop for repair. My problem was a gas valve which is $170 for the part and probably $40 for labor. I'm currently seraching out replacement furnaces but depth is a problem because of the wheel well. May be able to mount one of the Wave heaters in the space. Have you had any luck? I may have parts on mine if I decide not to fix it. Barry

Barry, I have a '65 Caravel that required a replacement heater and I was able to accomodate the need with a Wave "6" that fit wonderfully. I devised a panel for the old furnace opening to match the cabinetry and then attached the heater to it per instructions. (I did not use the recess kit that was available as the shape of it would have weakened the opening surround precipitously.) My new panel was even large enough to accomodate the opening required for gas hook-up, and the line was long enough to reach to the left side of the heater (It was attached to the right side of the old heater.) Be careful bending the gas line and you should have no problems with connections. I am very watchful when the side goucho is extended due to close clearance, but, otherwise, things work well. All in all, am quite happy with it.

[TGK]

I have been looking into options for heating a 23ft Safari while boondocking that do not require electricity for the fan and also address the issue of catalytic heaters consuming inside air. I came across two marine heaters designed for heating boat cabins that run on propane. The Force10 brand vents outside but consumes inside air for combustion. However, the Dickinson Marine Heaters have two new LPG heaters that combine outside air intake in the vent tube. BTU range is 5,500 - 7,500 for the smaller unit and 7,000 - 9,700 for the larger. Dickinson is located in Everett, Wa. and sells thru various marine supply houses. The web site is ww.dickinsonmarine.com. They are made with stainless steel & come with a rear mounting plate to protect the surface it is mounted on. One would have to clarify side clearance to combustibles. Both units have a decent size ceramic glass view window for watching the flame for ambience. It comes with stainless vent pipe and deck fitting and cap. An appropriate mounting place would have to be found that allowed venting through the roof. Not sure if the curved roof of the Airstream would present a problem for the vent cap.

As for the bottom line, I think they range in price from $500 - $600. I called Dickinson in Everett and the guy told me they have sold them for use in campers and trailers. I'd be interested in hearing whether anyone has ever had experience with these.

[Stefrobrts]

I'm going with the Atwood mentioned in the thread above - if I ever finish my floor repair! I don't care for the catalytic heaters, I worry about exhaust gasses not being vented outside. There was one in the Bambi we had breifly, and it really put out the heat, but I wouldn't want to be sleeping with my head a few inches away from it (which is how it works out in the Caravel).

[malconium]

The Dickson Marine site mentioned also carries a couple of hot water heating units with built in blowers that seem like they could work very well for heating an AS. You would just need a circulation pump to pump hot water to them from your water heater. Check them out at the bottom of the listed page.
http://www.dickinsonmarine.com/shop5...es-heaters.asp

For a little more information on hot water heating check out the following thread:

http://www.airforums.com/forum...ad.php?t=15479

By the way the porpane heaters shown seem pretty neat. I had been wondering if anyone made a propane fired fireplace that was small enough to put in an AS and now I know that someone does.

Malcolm

[TGK]

While the Dickinson Marine Heaters are certainly not cheap, the prices shown on their website are list. I saw them elsewhere selling in the $500 - $600 range. It seems like most things built for marine appliations cost more but then they are often built to a higher standard out of necessity. I like the fact that they pull in combustion air from the outside unlike catalytic heaters. While they come with a blower fan, I was told it is not necessary for effective heating as they do a generate a great deal of radiant heat.