ammonia absorption

[hydrocarbons]

hey all,

fridgy from adelaide, the bloody father and law has an old Dometic
RM 2300, of cause it worked last time he used it and now it dose not!

1st the control circuit is fine heaters are fine and gas is all fine, when it is switched on the elements heat and i can hear, like the sound of falling of water, and no cooling on either of the coils, What i would call the discharge pipe gets hot but still no cooling. i assume there has been a leak of some form but is it the hydrogen or ammonia or if one then both????

2nd if leaked how do i go about repairing???

and 3rd anyone know of a really good site involving info on this topic and diagnostics

any help much appreciated

bloody family jobs

[Tiger93rsl]

Thats funny you posted this I was just telling a coworker about an old absorbsorption system I riped out about 5 years ago and replaced it with a split system. Do the same, nobody workes on thoses types of systems any more. In the 15 years I've been doing this I've only seen 2 of these systems still in use.

[ptrck]

hi hows it goin, i used to work on a lot of arkla servel and dometic products,any way this might sound weird what i am going to tell you to do,but it will proboaly work if you do not have a leak which you probaly dont.take the unit and turn it up side down for 24 hrs, this will allow the ammonia to remix with the solution [hexaventalant]. you generator is weak on ammonia,then after 24 hours turn it back up right and let stand for about 4 hours.these systems do not have solution pumps so when it seperates this is the only wat to combine the 2 again. so if you are gas firing it slow fire it so not to boil off the ammonia to fast,if it is eletric heaters plug it in and warm it then un plug for a min or so and repeat for 10 min and then plug it in and hope for the best. ley me know how it goes. good luck pat

[mcr]

hi hows it goin, i used to work on a lot of arkla servel and dometic products,any way this might sound weird what i am going to tell you to do,but it will proboaly work if you do not have a leak which you probaly dont.take the unit and turn it up side down for 24 hrs, this will allow the ammonia to remix with the solution [hexaventalant]. you generator is weak on ammonia,then after 24 hours turn it back up right and let stand for about 4 hours.these systems do not have solution pumps so when it seperates this is the only wat to combine the 2 again. so if you are gas firing it slow fire it so not to boil off the ammonia to fast,if it is eletric heaters plug it in and warm it then un plug for a min or so and repeat for 10 min and then plug it in and hope for the best. ley me know how it goes. good luck pat

I was going to tell him the same thing. Had a guy with one of those Dometics with the same symptoms. Told him he had to get it out of his RV and turn it upside down to remix the ammonia. He asked me if he shook it real hard would it come back faster. He was ready to leave on a trip. I told him I didn't think so and asked him how he would shake it. He said his wife had one of those old stomach vibrators with the belt thingy.

[Tiger93rsl]

The thing with those older systems the generator may become slighly porious in spots over time allowing the Hydrogen in the amonia to seep out of the system. Effecting the cooling capacity of the system.

[hydrocarbons]

i love that, will it work faster if i shake it... hah

thanks guys im going out to flip it over now!!

ill keep u posted

[DougO]

If there is a yellow stain around the boiler ( discharge pipe ) there is a very good chance that it is cracked and is leaking. Also if you happen to open the fridge and smell ammonia that is also a telltale sign of a leak.

There are replacement cooling systems available, do a search on some of the RV sites. There is a place that has refurbed units available or check with your local RV dealer.

You might check for RV surplus dealers and see if they have any scratch and dents units available for a discount. New RV fridges are not cheap, the sratch and dent ones are a little less. If you RV fridge is more than a few years old it may not be worth the $$ the repair.

Always make sure that the fridge is level when ran, if it is more than a little bit off center it will over heat the boiler and crack it.

Trust me been there done that.. Stupid thing is still not fixed/replaced.

But yes do the turn it over procedure, hopefully it can be salvaged.

[hydrocarbons]

followed your instructions to the letter pat,

thought we were on to a winner too, turned the right way up let it sit and continued with your start up procedure, evaporator started to get cold and i was rapped, walked away and came back an hour latter expecting it to be frosty and it wasn't, and i could also smell the ammonia this time, so it definitely let the ammonia mix up again but also reviled that it must be leaking

thanks for your help any other ideas on how to repair??

is he ammonia the only media leaking???

if it is replaced will it work again???

is there any system access???

[Tiger93rsl]

followed your instructions to the letter pat,

thought we were on to a winner too, turned the right way up let it sit and continued with your start up procedure, evaporator started to get cold and i was rapped, walked away and came back an hour latter expecting it to be frosty and it wasn't, and i could also smell the ammonia this time, so it definitely let the ammonia mix up again but also reviled that it must be leaking

thanks for your help any other ideas on how to repair??

is he ammonia the only media leaking???

if it is replaced will it work again???

is there any system access???

The ammonia is the only refrigerant in the system. because of leak you have in the refrigeration circuit you have lost enough refrigerant in the system to adequately cool the cabinet. Because the refigeration circuit is sealed and this as an ammonia system there is no way to add refrigerant. At this point you are stuck with two options either go to a RV dealer and find you a rebuild fridge. Or take that one out and go to walmat and get you a small 110V fidge they will fit perfect in the hole and it will only run you a little over $100.

[ptrck]

i half to agree with tiger, i mean i you have the experience level to weld in a steel acess valve on your sca or solution cooled asorber tank and then go and find a chemical supplier for your nh3/ammonia.it can be done but the hassel of out weighs the heart ache. so put the old girl to sleep and move on--sorry about that chief.--pat

[hydrocarbons]

Understood. i have the same trouble explaining that to customers all the time.

what about these replacement systems iv seen

http://cgi.ebay.ca/DOMETIC-NORCOLD-R...QQcmdZViewItem

bit expensive there. do you know of any any where they can be purchased????