MANOMETER?

[patrick crawford]

i have a 16' casita with the small fridge. i recently completed a 3 month trip and all but 3 days i was forced to use my trusty coleman cooler to keep a chill on stuff. the flame never went out, the burner and the related stuff were cleaned and carefully reassembled prior to departure. i've about had it with that cursed box but since i purchased one i'll use that manometer to determine if there's proper pressure on the gas line. problem is i've no idea there to connect the meter. while at quartzsite this year i searched out as many fridge gurus as i could find. they could all tell me where they performed this procedure on their 17's with the big fridge but not on mine. i've looked and looked at mine but no ah ha moments have occurred. so...if anyone can shed some light on this dark problem please let me know. a photo would be worth more than a thousand words.



oh, and here's a tip...that dysfunctional fridge makes a great bread box. no moldy bagels and the crackers remained crispy.



p@

[Steve L.]

I have the same unit as you, RM2193.

My principle problem was with the door not sealing closed. The hinge on top was loose and the door would not seal well and keep the cold air in. I eventually, after repeated measurements, drilled a hole on the little shelf on the top to give me access to the screws on the top to tighten the door in it's correct location.

The hole size was selected that gave me some wiggle-room in locating the hole and sized so I could put a stainless hole plug in. I went so far as buying replacement hinge straps so that I could locate where the screw was under the fiberglass. I siliconed the plug in place but it's removeable. Somewhere I have a picture of the plug location but I can't find it at the moment.

I, too, have the manometer (Yellow Jacket). If I were inclined to measure the pressure I would loosen one of the gas supply lines. I can't find a pressure tap point like the bigger fridges have either.

Almost every trip the contents spill out. The little twisty thing at the top of the door doesn't do the job. I've been plotting some way to have a positively closed door. No decision yet.

In the end, I bought the small Dometic fridge/freeze electric cooler and the means to lock it to the curb side wheel while camped. During the trip it runs off the inverter in the tow. Until I sort through how to keep the door shut and regain confidence in the on board fridge, it does the job.

[ZachO]

Well I guess it'll be different on different models, but here's where I tested mine.





I forget which model...but I think it might be the same as yours. I've had endless trouble getting mine to cool efficiently.

[Steve L.]

Mine doesn't look like that. That bolt seems to just before the burner and would be handy for pressure checks for sure.

FWIW, I put a water heater reignitor in there to light the fridge to see if I could keep the pilot lit while travelling. It works to light the burner but it doesn't keep it lit while travelling. I would try a baffle next if I didn't have the travelling electric cooler (Dometic CFX-28).

My tow vehicle doesn't put out enough amps (~10a) to run on DC.

And lastly, you can see some of the AC plug wiring zip tied to part of the condenser. Casita straps this wire too tight so that travel vibrations pull the plug out the receptacle enough for the fridge not to work on AC. Put a little slack it there. It only has to pull out a gnat's eyebrow to interupt the 120 AC.

Two extra credit answers to questions nobody asked.

[ZachO]

It sure is!

And correction, my fridge is a 2301.

[patrick crawford]

Almost every trip the contents spill out. The little twisty thing at the top of the door doesn't do the job. I've been plotting some way to have a positively closed door. No decision yet.

steve, do you have that pin with the rubber or plastic tip that fits into the bottom of the door to a matching hole in the fridge door frame? i found inserting that pin is crucial to preventing the door opening issue. also, i created a wind blocker out of flashing material that stopped the flame from blowing out.

and, i still can't figure out where to connect the manometer....

p@

[Steve L.]

I don't, or at least haven't found a pin and there isn't one in the parts list for my version of the fridge. It has a twisty bit of plastic (214) that is part of the frame/hinge strap that catches another piece of the door (239) to lock it closed. But if the the door is shifting slightly it just pops open.

[starbrightsteve]

I don’t know the size and thread type of the hole that the orifice plugs into but that may be an option for connecting the manometer. If that works, make sure you run the burners on the stove while making a measurement or adjustment.

[ZachO]

I feel lucky. On my first camper, which I bought a new fridge for (probably a 2193), I had that same problem. And it was a tiny motorhome, so when I went around a sharp corner and the fridge opened and dumped everything, I knew it. You could call this better or worse...Not sure if I'd rather know it happened right in the middle of a tight turn, driving, or find out only when I got to camp.

Guess it's better to clean up the mess sooner than later.

But with my current fridge, this has never been a problem. Same latch, more or less, but for whatever reason, it works.

I think the the only option for testing pressure if the fridge doesn't have a dedicated port is to unscrew the propane attachment and find a way to fit your manometer hose over the actual propane line.

[starbrightsteve]

I had another thought or two. As Steve said, you could disconnect the gas line to the fridge and using some adaptors, measure the system pressure at that point. You don’t have to measure at the fridge. Another place that might have a test Port is at the water heater.

[starbrightsteve]

In any case, it would be nice to know how you finally measure the gas pressure. There are a lot of smaller fridges out there and your findings would be helpful to everyone.

[Raspy]

When trying to diagnose the gas system and determining the correct gas pressure, you should measure the pressure in three places in three different conditions.

First is the system static pressure. This is with all appliances off, the gas turned on at the tank and the pressure measured in the gas supply piping to the appliances. Anywhere in this pipe is fine

Second is to measure the pressure in the pipe with all appliances running. Since the fridge is the problem appliance here, the gas pressure should be measured at the fridge gas valve inlet side, with the stove burners on and the heater on.

Third, the gas pressure should be measured after the fridge gas valve, in the line running to the burner. This should always be done with the burner on and should be done with the other appliance running and also with them off. Often, there is a plug in the gas valve with 1/8" pipe thread for this purpose, near the outlet port. If not, a Tee can be installed in the outlet tube.

Then you have a real comprehensive chart of pressures under real conditions.

The delivery pressure should be about 10" to 11" water column. It should not creep up with the appliances off and it should not drop too much with everything running. The most critical measurement is the one after the fridge gas valve and before the burner, with everything else running. You can do that one first and if it's fine the rest don't matter too much.

The burner orifice can get clogged with flame byproducts or spider webs. So make sure the orifice is clean. A welding torch "tip cleaner set" is very useful for this, or just a small piece of wire. Drills are not a good idea. Some have a tiny filter in the orifice fitting that filters before the actual orifice hole. You can probably blow backwards through this to clear it.

Mine used to blow out on every trip, until I made little baffle out of galvanized flashing to keep the wind away.

[gordon2]

Originally Posted by Raspy

....
The burner orifice can get clogged with flame byproducts or spider webs. So make sure the orifice is clean. A welding torch "tip cleaner set" is very useful for this, or just a small piece of wire. ...

Image from the Dometic service manual...

[ThomasE]

Originally Posted by Steve L.

I don't, or at least haven't found a pin and there isn't one in the parts list for my version of the fridge. It has a twisty bit of plastic (214) that is part of the frame/hinge strap that catches another piece of the door (239) to lock it closed. But if the the door is shifting slightly it just pops open.

I had the same problem as you, over rough roads my door would pop open. Low tech solution, use a piece of blue painters tape over the plastic part that rotates, tape it down to the fridge front. That prevents it from rotating. Since I got tired of replacing the tape, I removed the whole rotating gizmo and inserted an Ikea hex key that fit through the hole into the door, which prevents the door from opening until you remove it. I used a hex key just because it fitted the hole, you could use anything like a nail.

[Steve L.]

That sounds promising. I'm going to check that out when the temperature goes up enough that I can spend more than 30 seconds out in the cold. I've gotten to be such a wuss as I've grown older...

[ZachO]

I used to make fun of people for moving to Florida or Arizona. I still won't say that I'll ever do it, but as I get older, I can sure see the appeal.

[Steve L.]

I call Florida the La Brea Tar Pits of the east. Some day, thousands of years in the future, alien archaeologists will wonder why there are proportionally so many bones of old people in this one area.

[ZachO]

Oh, they'll wonder that and quite a few other things, I'm sure.

[patrick crawford]

ok...here's where i am so far...my regulator (at the tanks) is a marshal megr25h and has a test port. i tested there and got 13.28 wc (it was higher at first but after a few min settled down and remained constant). the black circle under the tank selector knob covers an adjustment screw. i've not messed with that yet but i may. turning the gas on for the fridge causes the pressure to drop to 13.15. quite frankly i'm not sure what these numbers mean to me. i obviously have enough pressure to operate the fridge but, i'm wondering if it might be too much?

any comments will be appreciated...

p@

[ZachO]

11-12". 13 is too high, but then it's supposed to be 11-12 at the fridge. I don't know how much the pressure drops between the regulator and appliances, or, being a supposedly closed system, if there shouldn't be any drop at all. I don't know...

Too high or too low will both affect the fridge. I don't know how, exactly...I do know that mine was also high, and my fridge doesn't cool as well as it should. Pressure is only one of many problems mine has, but the pressure being too high couldn't have been helping.