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Foretravel Motorhome Forums => Foretravel Tech Talk => Topic started by: Tony Pasquale on July 28, 2016, 02:52:52 pm

Title: Refrigerator section does Not cool on LP, freezer works fine.......any thoughts
Post by: Tony Pasquale on July 28, 2016, 02:52:52 pm
Need some thoughts on a 2 way Dometic RM1282 refrigerator problem: The refrigerator section does not cool while on LP, however, the freezer section works fine on LP plus the refrigerator cools and freezes okay while connected to the A/C. 
I have cleaned the burner and I am getting a nice blue colored flame.  Checked all the 12 volt wires and they have power.  I changed out the control board with a new Dinosaur Micro p-711 and still the same problem, guess I didn't need the new board, it looks new/good though... ::)

I am looking to stay with the absorption system at this time so any thoughts where to check next would be appreciated.

Tony
 
Title: Re: Refrigerator section does Not cool on LP, freezer works fine.......any thoughts
Post by: bogeygolfer on July 28, 2016, 03:02:09 pm
When mine was doing this, a tech suggested it might be the "thermistor", but it turned out to be the cooling unit.  You might check this, just in case you are luckier then I was.

Chris
Title: Re: Refrigerator section does Not cool on LP, freezer works fine.......any thoughts
Post by: Chuck & Jeannie on July 28, 2016, 03:10:31 pm
Google to the rescue (maybe...or maybe not)

Note the identity of the good-looking, well-known, highly paid Technical Advisor who posts suggestions in the first link:

Dometic Refrigerator: Freezer Works But Refrigerator Won't Cool - Systems... (http://community.fmca.com/topic/4046-dometic-refrigerator-freezer-works-but-refrigerator-wont-cool/)

RV Refrigerator Repair 101: How To Diagnose Problems With RV Refrigerators |... (http://rv-roadtrips.thefuntimesguide.com/2014/02/rv-refrigerator-repair.php)

http://www.nationalserroscotty.org/resources/dometic-service-manual.pdf
Title: Re: Refrigerator section does Not cool on LP, freezer works fine.......any thoughts
Post by: Mike Leary (RIP) on July 28, 2016, 03:20:03 pm
Note the identity of the good-looking, well-known, highly paid Technical Advisor who posts suggestions in the first link:
Never heard of him, but I do know there is a fresh Dometic in his ex-coach.  ^.^d
Title: Re: Refrigerator section does Not cool on LP, freezer works fine.......any thoughts
Post by: John and Stacey on July 28, 2016, 03:24:55 pm
Just went thru the same issues...Replaced it with a Samsung (RF18HFENBSR) We are thrilled.
Title: Re: Refrigerator section does Not cool on LP, freezer works fine.......any thoughts
Post by: wolfe10 on July 28, 2016, 03:25:16 pm
Thermister functions the same on 120 VAC or LP, so I would eliminate that for right now.

BTU's of propane are the same as the electric element IF two thing happen:

1.  Gas pressure is correct (11 column inches of HG)  CHECK IT!
2.  Burner area is clean, including gas jet and burner tube.
Title: Re: Refrigerator section does Not cool on LP, freezer works fine.......any thoughts
Post by: Tony Pasquale on July 28, 2016, 03:38:19 pm
When mine was doing this, a tech suggested it might be the "thermistor", but it turned out to be the cooling unit.  You might check this, just in case you are luckier then I was.

Thanks Chris, 
While on A/C I checked the "thermistor" by moving it up, and the down and it changed the temperature alright. Since your post I google "thermistor" and just found a write up from another Dometic model on how to check if the thermistor is working by measuring OHM readings while disconnected and placed in a glass of Ice and water.

Title: Re: Refrigerator section does Not cool on LP, freezer works fine.......any thoughts
Post by: Mike Leary (RIP) on July 28, 2016, 03:41:25 pm
It could have been Tab Hunter (aka Brett Wolfe) that replaced the existing Dometic with a 3962 "New Generation" fridge in 09. Works perfect! On a previous coach, we did have the Dometic re-built, lasted a year!  >:D
Title: Re: Refrigerator section does Not cool on LP, freezer works fine.......any thoughts
Post by: Tony Pasquale on July 28, 2016, 03:44:43 pm
Google to the rescue (maybe...or maybe not)

Note the identity of the good-looking, well-known, highly paid Technical Advisor who posts suggestions in the first link:
will check googled items and identity.
thank you Chuck
Thermister functions the same on 120 VAC or LP, so I would eliminate that for right now.

BTU's of propane are the same as the electric element IF two thing happen:

1.  Gas pressure is correct (11 column inches of HG)  CHECK IT!
2.  Burner area is clean, including gas jet and burner tube.
will check propane pressure and reclean burner area.

Thank you Brett
Title: Re: Refrigerator section does Not cool on LP, freezer works fine.......any thoughts
Post by: Tony Pasquale on July 28, 2016, 04:18:16 pm
It could have been Tab Hunter (aka Brett Wolfe) that replaced the existing Dometic with a 3962 "New Generation" fridge in 09. Works perfect! On a previous coach, we did have the Dometic re-built, lasted a year!  >:D
Not Tab Hunter....
Hopefully I can fix this refrig myself .....

Thanks Mike
Title: Re: Refrigerator section does Not cool on LP, freezer works fine.......any thoughts
Post by: Pamela & Mike on July 28, 2016, 04:35:22 pm
Tony.

You also need to go up top and remove the vent cover and find the burner tube stack.  It should have a "T" on the top. After the unit has had time to cool remove the "T" and it should expose a round wire loop.  Grab loop (after it has cooled also or you will get burnt fingers) and pull it out of the burner tube. It should be about 18" long piece of wire with a spinner bait looking piece of metal on the end. (Here is a couple of pics of what you are looking for from a fridge that is in for repair)  Clean this flame swirler along with running a tube brush down the stack. (just like cleaning a chimney on a fireplace) Doing this should help with your heat transfer problem. Re vacuum around your burner as you will have covered the area with soot.

Pamela & Mike

Title: Re: Refrigerator section does Not cool on LP, freezer works fine.......any thoughts
Post by: Pamela & Mike on July 28, 2016, 04:43:04 pm
Tony,

At least the last 2 pics are pointed in the proper orientation.

Pamela
Title: Re: Refrigerator section does Not cool on LP, freezer works fine.......any thoughts
Post by: Tom Lang on July 28, 2016, 06:46:49 pm
That's how mine was misbehaving shortly before catching fire. Be careful.
Title: Re: Refrigerator section does Not cool on LP, freezer works fine.......any thoughts
Post by: wolfe10 on July 28, 2016, 07:05:30 pm
Indeed, one of the first symptoms of a failing cooling unit is that the freezer cools ("coolant" goes through the freezer before going on to the refrigerator) and the refrigerator does not.

Certainly, there are other causes.
Title: Re: Refrigerator section does Not cool on LP, freezer works fine.......any thoughts
Post by: John Morales on July 28, 2016, 07:33:06 pm
If you can't resolve the issue you can always rebuild it.

Brand New Lifetime Warranty Cooling Systems - Dometic Models 1 - Store (http://www.arcticoldstore.com/dometic-models/?gclid=Cj0KEQjw2ua8BRDeusOkl5qth4QBEiQA8BpQcN5DMu3aYbITo1I2UxLDN9i-altouLXVOVjVhB0kC8saAoBN8P8HAQ)
Title: Re: Refrigerator section does Not cool on LP, freezer works fine.......any thoughts
Post by: Carol & Scott on July 28, 2016, 09:30:08 pm
FWIW - When we encountered this issue 6 or 7 months ago we found that the cost to rebuild with a new cooling unit was about the same as installing a new Samsung res. refer.  That was with me doing all of the labor.  As I recall a good new replacement cooling unit was about 1K.  We installed the 18 cu ft Samsung somewhat under that.  Glad we did.

Sorry to get off track.  ;D

Hope your problem is solved easily and inexpensively.
Title: Re: Refrigerator section does Not cool on LP, freezer works fine.......any thoughts
Post by: Tony Pasquale on July 29, 2016, 08:18:13 am
Tony.

You also need to go up top and remove the vent cover and find the burner tube stack.  ....
Pamela & Mike
Thanks Mike,  Good Info and great pictures, the frig is on A/C right now, I will go on top as soon as cool and no rain, 3 days of rain is forecast.   

That's how mine was misbehaving shortly before catching fire. Be careful.
Indeed, one of the first symptoms of a failing cooling unit is that the freezer cools ("coolant" goes through the freezer before going on to the refrigerator) and the refrigerator does not.

Thanks Tom and Greg,
When I spoke with a local RV service center telling them about problem and what I had done so far with no success, they mentioned possible blockage in cooling tube, is that what your saying and is there anyway to unblock maybe a hammer?

I did make an appointment with them 2 weeks from now so I will continue to try and fix.

Before that, I need to re-clean the burner assembly, check LP and clean burner tube from roof side.

Thank you and this forum as always most helpful place! Hopefully, a fix is possible!
Tony
Title: Re: Refrigerator section does Not cool on LP, freezer works fine.......any thoughts
Post by: Tony Pasquale on July 29, 2016, 08:32:26 am
FWIW - When we encountered this issue 6 or 7 months ago we found that the cost to rebuild with a new cooling unit was about the same as installing a new Samsung res. refer. 
If you can't resolve the issue you can always rebuild it.

Brand New Lifetime Warranty Cooling Systems - Dometic Models 1 - Store (http://www.arcticoldstore.com/dometic-models/?gclid=Cj0KEQjw2ua8BRDeusOkl5qth4QBEiQA8BpQcN5DMu3aYbITo1I2UxLDN9i-altouLXVOVjVhB0kC8saAoBN8P8HAQ)

Saw that website Articold Store when problem first started they want $1200 plus $250 shipping for the RM1282 cooling unit and at the time there was no guarantee that it would fix my problem. I did look at their installation video which is very informative, IMO worth a look for by a RV owner.

Scott not ready yet to switch ....but you never know at $1450 delivered from Articold Store or $1350 installed at Amish in Indiana,  I may just end up going Residential!

Tony

Title: Re: Refrigerator section does Not cool on LP, freezer works fine.......any thoughts
Post by: Roger & Susan in Home2 on July 29, 2016, 08:52:24 am
Tony, the 19 cu ft French Door Samsung is almost twice as big as the original refrigerator.  The freezer space is much more usable.  If your original is 36" wide you can add a narrow tall cabinet next to the Samsung.  After selling the Dometic without the wooden door panels on Craig's list our net cost to do it ourselves was about $800.
Title: Re: Refrigerator section does Not cool on LP, freezer works fine.......any thoughts
Post by: Carol & Scott on July 29, 2016, 09:33:51 am
In hind sight the decision was easy.  While we were contemplating this problem seemed almost overwhelming.  Cost, change, battery power while boondocking and many other concerns.  We did not put in a narrow pantry like Roger did.  We did not have a work shop to build so later we installed a wider trim piece.  It's all good.  Glad we did it.  Lots of posts here for you to investigate if you choose.  ;D
Title: Re: Refrigerator section does Not cool on LP, freezer works fine.......any thoughts
Post by: Chuck & Jeannie on July 29, 2016, 09:35:28 am
....but you never know at $1450 delivered from Articold Store or $1350 installed at Amish in Indiana,  I may just end up going Residential!
Plus, never again having to worry about a ammonia-fueled fire - PRICELESS.
Title: Re: Refrigerator section does Not cool on LP, freezer works fine.......any thoughts
Post by: wolfe10 on July 29, 2016, 09:53:56 am
Tony,

Blockage is caused by high temperatures (generally from running out of level-- even for short periods of time).  That precipitates the chromate that is in there as a rust inhibitor. The blockage is cumulative.

You really can not unplug one.

Again, rule out all other causes before concluding that the cooling unit is bad.

Have even seen one of them that failed to cool properly due to bird nest in vent. That was a cheap fix.
Title: Re: Refrigerator section does Not cool on LP, freezer works fine.......any thoughts
Post by: Miz Dani on July 29, 2016, 09:54:25 am
Come on, Tony, pull the trigger....  8)  ....this'll be my next upgrade! (then solar, then new windows, then FBP, then wood work & shelving in the bathroom, and on and on and on it goes...where it stops, nobody knows!) ....life is short, get the residential... 
Title: Re: Refrigerator section does Not cool on LP, freezer works fine.......any thoughts
Post by: bogeygolfer on July 29, 2016, 10:31:12 am
We elected to have a residential fridge installed when ours went kaput, and have really enjoyed it.  But, we don't do any dry camping or boondocking.  I do miss the look and fit of the original fridge (this one protrudes a couple of inches out from the cabinet, which does make a difference in our coach).

Btw, we recently lost power at our enclosed storage facility and our coach sat there for 2-1/2 days with a freezer full of ice.  When I finally got to the coach, we still had ice in the freezer despite 90 degree temps here.  I was very surprised as I had never gone more than 4 hours with a cold fridge unplugged.

Best of luck, whatever you decide.
Title: Re: Refrigerator section does Not cool on LP, freezer works fine.......any thoughts
Post by: Doug W. on July 29, 2016, 10:59:49 am
You really can not unplug on
[/quote]


While boondocking on a Mexican beach many Winters ago I had my fridg stop cooling the lower compartment after stuffing freezer compartment full of unfrozen fish.
Took the fridge out and laid it on its side for 24 hours, called burping. It was the fix and never had any problems after that...

Burping an RV refrigerator to remedy a blocked cooling coil | Mobility RV... (http://rvsteve.com/index/2014/06/24/burping-an-rv-refrigerator-to-remedy-a-blocked-cooling-coil/)
Title: Re: Refrigerator section does Not cool on LP, freezer works fine.......any thoughts
Post by: Tony Pasquale on July 29, 2016, 11:11:19 am
... original is 36" wide you can add a narrow tall cabinet next to the Samsung.  After selling the Dometic without the wooden door panels on Craig's list our net cost to do it ourselves was about $800.
Hi Roger,
Great job selling the Dometic Refrigerator, was it a working model when you sold it?  installing the residential refrigerator takes some wood working tools plus removing and adding frig to coach will be tough no one nearby to help. The other hurdle is I am definitely challenged on electrical skills as I would want to add a dedicated inverter.
However, We will see how this will plays out, thanks for the suggestions
Come on, Tony, pull the trigger....  8)  ....this'll be my next upgrade! (then solar, then new windows, then FBP, then wood work & shelving in the bathroom, and on and on and on it goes...where it stops, nobody knows!) ....life is short, get the residential... 
Thanks Dani for the push, I have added upgrades also, I am just trying to handle this myself then I will review other alternatives if need be.

While boondocking on a Mexican beach many Winters ago I had my fridg stop cooling the lower compartment after stuffing freezer compartment full of unfrozen fish.
Took the fridge out and laid it on its side for 24 hours, called burping. It was the fix and never had any problems after that...

Doug, I read the article and will use it, burping, as a last resort!
Thank You!

Thanks everyone for the help and suggestions! ^.^d
Tony




Title: Re: Refrigerator section does Not cool on LP, freezer works fine.......any thoughts
Post by: Travelin' Man (RIP) on July 29, 2016, 11:31:18 am
Tony,

Blockage is caused by high temperatures (generally from running out of level-- even for short periods of time).  That precipitates the chromate that is in there as a rust inhibitor. The blockage is cumulative.

You really can not unplug one.

The best way to protect your cooling unit is to shut it off whenever it's out of level..........that way high temperatures aren't achieved.
Title: Re: Refrigerator section does Not cool on LP, freezer works fine.......any thoughts
Post by: Mike Leary (RIP) on July 29, 2016, 11:38:15 am
The best way to protect your cooling unit is to shut it off whenever it's out of level..........that way high temperatures aren't achieved.
Is that still true? I know on our older coaches it was important, but in looking through my manual on our newer Dometic, they say, "if one is comfortable walking around the coach when landed, the fridge will operate fine." That being said, we still level, big time. ^.^d
Title: Re: Refrigerator section does Not cool on LP, freezer works fine.......any thoughts
Post by: Travelin' Man (RIP) on July 29, 2016, 12:43:53 pm
There is a small number of degrees tolerance to being level,  but rather than taking a chance on miscalculations I go for level,  which is simple with the air ride leveling feature.

Plus, the tubing is only pitched one way,  so IMHO being a few degrees out  of level isn't the same in both fore and aft directions..

When I get back home I'll just shut the reefer down
until next time we go somewhere.  I have never had a cooling unit go bad that was new when I got it.
Title: Re: Refrigerator section does Not cool on LP, freezer works fine.......any thoughts
Post by: wolfe10 on July 29, 2016, 12:55:23 pm
Is that still true? I know on our older coaches it was important, but in looking through my manual on our newer Dometic, they say, "if one is comfortable walking around the coach when landed, the fridge will operate fine." That being said, we still level, big time. ^.^d

Yes, absolutely true.

And, with an absorption refrigerator, I would certainly fit it with an ARP controller.  I have attended one of his seminars and he mildly tips  a working cooling unit.  On the screen is an instant readout of boiler temperature. It rises shockingly fast.

So, it is not just while parked that you need to be level.  If you are climbing a 5 miles grade, the boiler temperatures will rise high enough to allow chromate to precipitate.

The ARC controller automatically turns of the refrigerator and then restarts is when boiler temperature drops.

Title: Re: Refrigerator section does Not cool on LP, freezer works fine.......any thoughts
Post by: Mike Leary (RIP) on July 29, 2016, 01:13:03 pm
The ARC controller automatically turns of the refrigerator and then restarts is when boiler temperature drops
Thanks, Brett, never heard of it, did a search, not spendy compared to a fresh Dometic! So, my "muffin fans" do something different, I assume? Ah, the "bells and whistles" never end.
Title: Re: Refrigerator section does Not cool on LP, freezer works fine.......any thoughts
Post by: wolfe10 on July 29, 2016, 01:39:34 pm
Thanks, Brett, never heard of it, did a search, not spendy compared to a fresh Dometic! So, my "muffin fans" do something different, I assume? Ah, the "bells and whistles" never end.

The muffin fans help the cooling capacity.

The ARP controls/turn on and off the cooling process.
Title: Re: Refrigerator section does Not cool on LP, freezer works fine.......any thoughts
Post by: Mike Leary (RIP) on July 29, 2016, 01:46:16 pm
The muffin fans help the cooling capacity. The ARP controls/turn on and off the cooling process.
And I also see it works whether the fridge is on a.c. or propane.  ^.^d  How come our coach is missing an ARP, or are they newer?
Title: Re: Refrigerator section does Not cool on LP, freezer works fine.......any thoughts
Post by: wolfe10 on July 29, 2016, 02:12:49 pm
ARP did not exist back then or it would have.

And, yes, your muffin fans are 12 VDC, so they can work when cooling on either 120 VAC or propane.
Title: Re: Refrigerator section does Not cool on LP, freezer works fine.......any thoughts
Post by: Pamela & Mike on July 29, 2016, 03:45:49 pm
Tony,

Take the back cover off.  Get a long screwdriver that you can use for a listening probe. Put metal end on absorption tank (that is the round tank that runs horizontally across the back) and your ear on the end of the handle of the screwdriver.  Now do you hear quiet or do you have a gurgling sound? 

Pamela & Mike
Title: Re: Refrigerator section does Not cool on LP, freezer works fine.......any thoughts
Post by: Tony Pasquale on July 29, 2016, 07:06:18 pm
Tony,

Take the back cover off.  Get a long screwdriver that you can use for a listening probe. Put metal end on absorption tank (that is the round tank that runs horizontally across the back) and your ear on the end of the handle of the screwdriver.  Now do you hear quiet or do you have a gurgling sound? 

Pamela & Mike
Mike, I will check tomorrow, question if I hear gurgling but refrigirator still not cooling ..... ? Just saying either way doesn't seem good if frig still not cooling...let you know tomorrow.
Title: Re: Refrigerator section does Not cool on LP, freezer works fine.......any thoughts
Post by: Pamela & Mike on July 29, 2016, 07:26:24 pm
Tony,

Your 1st post said the unit worked on 120vac just not on propane.  Depending on the noise report will help determine how well it is working on 120vac.  What would be good also would be to know what the temp is in the freezer (the most important) and what the temp is in the fridge side.  Let me be sure you know to listen while on electric. If it is quiet on electric it will be quiet on gas.

By the way gurgling and not cooling=bad

Pamela & Mike
Title: Re: Refrigerator section does Not cool on LP, freezer works fine.......any thoughts
Post by: Tony Pasquale on August 01, 2016, 08:08:09 am
Tony,

Your 1st post said the unit worked on 120vac just not on propane.  Depending on the noise report will help.....

By the way gurgling and not cooling=bad

Pamela & Mike

No noise present on A/C or LP then went up on coach roof and tried removing baffle but I did not have tools or proper angle to replace baffle once removed, more precise not exactly in condition physicaly to be playing around on edge of roof. I will check LP and confirm pressure at burner orifice is correct.

Tony