| Author |
Message |
Gary Stadler (Boogiethecat) (68.7.217.217)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, July 19, 2002 - 12:20 am: | |
I bought an older used Dometic 2-way from a guy.. model RH76, 1300Btu. About 4 ft tall, freezer =separate door on top. I Decided to fire it up before installing it, ("it works fine" he said) and I think it's ok but...
From the time I lit it it took about an hour until the freezer started getting cold. Two hours in the freezer was frosty on the bottom but the fridge section showed no hint of cold at all. 5 hours in the fridge is now cooling down and the coils in the fridge section are cold. All along I can easily hear the ammonia gurgling away, the pipe out of the burner box is hot and the top condenser on the back is hot-to- warm depending on where ya touch it. The question: is this about right? It seems slow but then I havn't used one of these in years and just don't remember.
Also the pizeo ignitor is apparently kaput... any wisdom on replacing it, ie where to open it up to find it? (or should I just add an aftermarket one instead of trying to replace this one)
Last, there are two hangy-dangly wires hooked to an electrode-looking thing in the burner box bottom...one is grounded but the other isn't hooked to anything but a cut-off crimp splice... any idea what it's for? (it's not the pizeo electrode, but it looks like another electrode maybe, or a thermal switch... or just a splice??)
Here's a photo:
http://www.heartmagic.com/DometicBurnerWires.JPG
Thanks!
Gary Stadler |
FAST FRED (65.56.25.163)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, July 19, 2002 - 5:24 am: | |
The BTU removal of a propane fridge is not as quick as an AC powered compressor.
The usual is to turn it on the night before your going to load it and go camping .
The Dometic folks will send you free literature , with which you can decide the wires purpose.
techservice@dometicusa.com
Have the model number ect in the request.
FAST FRED |
Peter Broadribb (Madbrit) (216.67.218.142)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, July 19, 2002 - 5:43 am: | |
Gary,
could that wire be the 12 volt connection?
From the picture, it looks like the burner is a little sooty. Have you opened up the inspection cover and cleaned off all the soot deposits?
My Piezo is a little suspect sometimes, so I simply open the outside inspection door and there is a small hole by the burner to light it through with a gas wand. The flame failure mechanism is easier to operate there too.
Peter. |
Gary Stadler (Boogiethecat) (68.7.217.217)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, July 19, 2002 - 8:47 am: | |
Cool. (no pun!) I've sent an email to Dometic. Thanks Fred.
Peter, definitely not a 12 volt connection 'cause this is a "2-way", only runs on 120 and propane! But thanks for a simple and very necessary idea... instead of ripping big ugly access holes in the side of my bus and the roof, I'm putting a little petite lovered hole in the side, 6x6", and a Nicro 24 hr solar vent on the roof. I never considered making the louvers hinged. Thanks to your comment I'll hinge the louvers and locate the hole where I can light the pilot manually. Didn't think of that!!
See, Once again the Board saves yet another somewhat intellegent guy from himself!!
Thanks!!!
....And I'll clean the soot...good idea too! |
Richard Bowyer (Drivingmisslazy) (66.190.119.82)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, July 19, 2002 - 10:13 am: | |
Gary, you might re-think the 6 inch louver. It takes quite a bit of air flow to remove the heat from one of these. For example, I have a twelve by twelve (approximately) vent on the side and two six inch muffin fans in the exhaust (on adjustable thermostat) and when it gets up in the high 90's or 100, I still have marginal cooling.
Richard |
Gary Stadler (Boogiethecat) (68.7.217.217)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, July 19, 2002 - 11:09 am: | |
Fast Fred said this in a prior post... I havn't found him to be wrong on many things...
**********
..."The "Hole" in the top of the coach fridge requirement is best met with a Nicro Fico solar vent.
Instead of a huge hole and prayers that the breeze is in the right direction ect, the $100 or so vent has a motor , solar cell and battery.
These make almost NO noise and need no maint.
One or two will have a fridge happily working , even when the coach is 110 inside with NO air cond.
The holes required are only 4 in diameter , install just one and see if your unit requires two.
***********
So that's the plan... I can always add fans and still (hopefully) not have a monster hole. I'm kind-of amazed that two 6" muffin fans hardly do your job- unless they are really weak they will make hundreds of cubic feet per minute more air than a Nicro vent, so something doesn't jive here... is the rear of your fridge sealed, and do you have lots of insulation on the fridge as well as the walls of your bus?
Cheers
Gary |
Richard Bowyer (Drivingmisslazy) (66.190.119.82)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, July 19, 2002 - 12:33 pm: | |
Gary, I did not build my conversion, so I really am unsure about the insulation. The recess for the fridge is paneled so I can not tell what is behind it.
No the rear is not really sealed. That is where the twelve inch louver allows air in to cool the system. Everything is sealed except for this louver.
By the way, I think the rule of thumb is that the outlet exhaust should be about twice the inlet without positive ventilation.
Richard |
Gary Stadler (Boogiethecat) (68.7.217.217)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, July 19, 2002 - 12:44 pm: | |
Thanks Richard,
I will probably go with a larger inlet then, but likely thru the floor to under the bus instead of thru the side, because where the fridge is makes even a smallish side hole fairly difficult to cut in. I guess I could also supply the air from inside the coach, it would be cooler air for the fridge... though it would suck some A/C air away, but probably not enough to make a big difference. Thanks for the suggestions!!
Cheers
Gary |
Don in WA (67.227.220.216)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, July 19, 2002 - 12:57 pm: | |
You should not use inside air for several reasons.
1. That would vent propane into the interior with a leak or failure.
2. If you take cool air out of the bus it must suck hot air in.
3. If you use ventilation fans, roof or otherwise you could reverse the flow throught the refer and suck air in from the refer top vent along with carbon monoxide from the burner. |
Peter Broadribb (Madbrit) (216.67.220.83)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, July 19, 2002 - 1:10 pm: | |
Don,
very valid points, especially #3.
I do not like the system of drawing air from beneath the bus either. You never know what inflamable gases could be lurking around down there. Someone spills some gas at the next door campsite and the fumes blow under the bus and Boom. I know a similar risk could be with a side vent, but doubtful as there is not the closed in area for the fumes to collect in.
There has to be an inspection access panel, so why not make it big enough to use as a vent. Color coded to match the paint scheme and it's nearly invisible, especially if one custom makes a flush fitting one and does not use the standard RV door.
How do the big conversion companies like Marathon do it?
Peter. |
Don in WA (67.227.198.181)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, July 19, 2002 - 2:31 pm: | |
I did not put a access panel in and use air from under the bus. Mine is kind of unique in that it has very heavy and deeply corrugated stainless side panels. Would be very hard to put an access panel in without looking bad. Put this refer in place of an electic only that previous owner had. If I was laying out a new conversion I would consider an inside wall with inlet from bottom and access through a rear panel from bathroom ect.
I installed it thinking that if I needed access I would do it later. That was 4 or 5 years ago and so far working great. Have access from the side under the counter for propane connection ect. Have to pull the refer for major access which I suppose I should do just for a good cleaning. Out of sight out of mind. |
Gary Stadler (Boogiethecat) (68.7.217.217)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, July 19, 2002 - 3:59 pm: | |
Not that I'm going to do it, but if you think about it, (just for the sake of argument) pulling air from inside the bus probably isn't bad at all. Answering Don's points from the "Devil's Avocado" standpoint,
(1) If you had an equivalent propane leak in a side-vented application, since the side-vent is often installed somewhat above floor level and the rear of the fridge is sealed, there could be a puddle of propane buildup back there which would catch the pilot and "boom". Vented into the cabin at floor level, you would smell it or your propane sensor would go off which it wouldn't if "sealed and side vented"... it's a wash- in my opinion don't have leaks in either case
...and vented to under the bus means the propane goes away much more safely than either of the above two cases...
(2) Yes, cool air would be taken out of the bus and hot air would be sucked in... but at the speed of only a few CFM. Very little extra demand on the A/C if it's on, no big deal if it's off, because your windows are probably opened anyway, and cooler air will always be going to the fridge elements which always helps on a hot day!
(3) At least my fridge has a whopping 1300 BTU input... at full tilt burning slightly less gas than a typical household stove with five pilot lights running...If you're power-ventilating the bus well enough that you pull air backwards out of the refrdg's rear into the cabin, the ratio of CO to air is going to be so small at that point because air is MOVING that it wouldn't make a difference. I doubt that even a CO detector would see it.
Jes' my opinion. I'm going to go with a vent thru the floor though, because all of the thought that this thread has made me do has convinced me this is the safest.
Oh, those wires on the back of my heater box? A 12 volt hot-wire ignitor..odd for a "non-12 volt" fridge!
Cheers
Gary |
Don in WA (67.227.213.69)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, July 19, 2002 - 10:33 pm: | |
"Just for the sake of argument"
1. Given the choice between going "boom" inside or outside, I choose outside. Don't want to bet my life on my nose (if I'm awake) or detector to tell me there is a problem that wound not have been one in a normal installation. Don't want to open the door on a coach full of gas either.
2. In order for the fridge to cool and not cook the refrigerant it has to have natural draft working at all times. If you have a tight coach where is the air going to leak in? Forget once and buy a new cooling unit. If you have to provide a fool proof inlet (one that is going to drive you nuts when underway) why not do it the normal way from outside directly to the fridge? Any pressurization when under way may very well blow out the fridge as that would be an uncontrolable outlet.
3.If you are pulling air backwards the fridge may not cool and risk damage to the unit. Most exhaust fans are mounted at the roof. CO would settle to the floor and fill the coach. That is why stoves/grills ect. tell you to not use them for heating. To much chance of build up of CO. Almost died from CO poisoning. Once was enough.
Love a good debate!
Many happy miles and smiles. |
Gary Stadler (Boogiethecat) (68.7.217.217)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, July 19, 2002 - 11:22 pm: | |
Round three....um...
(1) Yup, better "boom" outside than inside, but better not at all!
(2) True enough, tight coach wouldn't work, although that tight and people probably wouldn't last very long in there either...
(3) True enough. You make a good case!
Good spar, now I have to say I agree with you!!
Cheers
Gary |
John Biundo (Jbiundo) (64.175.37.23)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, July 20, 2002 - 1:29 am: | |
Wow, you guys are GOOD!
Now THAT'S the way to have a friendly disagreement! I may be going out on a limb here, but it even seems like you may have LEARNED something from each other... Holy debate club, batman!
Amazing. Wish it was always this civil! |
Don in WA (67.227.198.224)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, July 20, 2002 - 2:53 am: | |
Thats why I read these boards. Just trying to learn how to improve the one I have or do better on the next one. Just not possible to follow these boards and not glean lots of useful info. Every day I say 'why didn't I think of that' or 'I didn't know that was even possible'.
The great thing about a bus is you CAN have it your way. Now I only have convince my wife that we DO need another one to get it right!
The bad thing about these boards is that it makes it almost impossible to finalize a plan because just when I think I have the ultimate setup in mind, someone comes along with a new/better/simpler/more efficient/sexier/cheaper/cooler idea I just have to have! Such is life. |
FAST FRED (65.58.187.139)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, July 20, 2002 - 6:10 am: | |
You DO need to install a vent chute ,or ductwork, so the air hat comes off the heater element does not stay in the coach.
The easiest propane fridges to live with are the HOUSE not RV units.
All controlls in the front , propane ONLY , no circuit boards to burn out , and extra thick insulation , so the gas used is tiny.
This month Backwaods Solar is selling Servelle (built by Dometic)units for $1200 delivered to your door.
But they ARE bigger than the RV fridge outside dimensions.
FAST FRED |
Buswarrior (Buswarrior) (64.229.208.54)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, July 26, 2002 - 3:14 am: | |
Hello all.
Please be cautious about venting and what it is you intend the nasty fumes to do. The theories all go out the window, so to speak, as soon as you put that thing on the highway.
What worked as an input sitting still may turn into an outlet, vice versa, or both.
No doubt you all know that if you open the driver's window at speed, that it pulls air through the coach, all the way from the back, if you're relatively stock. In commercial service, the driver always knew if someone was smoking in the lavatory, all he had to do was open his own window and smell the fumes wafting forward.
Kind of makes the old smoking section in the back of the bus rather absurd, doesn't it?
The long and the short of it is: there will either be a big suction, or a big pressure, or both, acting on the interior of your coach. All depends on how you are configured as you go down the road. Windows open or closed, fans on or off, vents open or closed, etc.
So, please wonder what is going to happen to your careful plans for fridge venting while you are underway. (And how exactly are you going to accomplish a complete seal from the interior?!?!)
Perhaps that home electric refrigerator (and it's batteries and inverter) doesn't look so bad after all? (ROFL, here we go again!)
happy coaching!
buswarrior |
FAST FRED (63.215.226.188)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, July 26, 2002 - 5:37 am: | |
The need for a "complete seal ' for the gas fridge is to allow the heat and moisture to leave.
Its hardly a big problem to have a flame that is as big as a gas stove piolt light on and not vented out for a half day as you drive.
For months on end , of course the proper system would get rid of everything .
The 120v house fridge ONLY looks difficult for folks that wish to boondock for long times , for most RV's that just go from campsite PP to another , they can work fine with a good inverter.
FAST FRED |
Bradd B. Smith (Bbsrtbusproject) (208.26.165.148)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, July 26, 2002 - 1:45 pm: | |
Since it is a duel power fridge, why not run it 120 while underway when the gas should be turned off anyway? Invertor is a snap with the engine running. Just a thought. |
Jim Lewis (205.188.209.11)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, July 26, 2002 - 10:30 pm: | |
been a few years since I had one but I remember that you Need 12 volt to it even if its a 2 way. Someone must have book on installing one. |
Gary Stadler (Boogiethecat) (68.7.217.217)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, July 26, 2002 - 11:47 pm: | |
Nope, it's absolutely 110 and propane, no 12 volts. That little strange wire setup in the back of the burner box turned out to be a 12 volt aftermarket ignitor, but there's no 12 volts to the fridge otherwise.
I did find a 12/120 heating element on ebay and I'm strongly considering sticking it in and converting it to a three way, because so far I have no plans for an inverter,but as it sits, it's really only two choices, 110 or propane!!
Kind regards
Gary Stadler |
Dale Fleener (64.66.215.228)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, July 27, 2002 - 12:59 am: | |
As to the idea of using inside air to vent, I think that would be contrary to 'da book' and would give the insurance companies sonething to hang a claim denial on, if it was ever needed.
Almost no new RV's come with a 3-way refer nowadays, there is very little need for a 12V circuit. It will put a big drag on the battery bank and not really do a whole lot of good, and is one more thing to go wrong.
On a short trip, the refer should stay cool enough while it is turned off. If that's not enough, as distasteful as it may be, it is common practice to keep the propane lit on the road. I'm not condoning the practice, just saying it is done with almost no problems in practice. |
FAST FRED (63.215.239.204)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, July 27, 2002 - 5:07 am: | |
"just saying it is done with almost no problems in practice. "
About 100% of the RV's travel with the unit lit , only exception being the automatic 3ways that use 12V while on the road , at about 20A .
The 3 ways were designed so there would be no open flame as the buggys filled at the gas station .
Most Rvrs don't bother even to turn it off when refueling with gasolene , although its a law .
Using Under a pound of propane a day its easy to not even bother to switch to 120 for a PP overnite.
FAST FRED |