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outcaststudios Samba Member
Joined: February 09, 2015 Posts: 1728 Location: Maine
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morymob Samba Member
Joined: November 09, 2007 Posts: 4683 Location: east-tn
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Posted: Fri May 22, 2015 5:01 am Post subject: |
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Recently i plugged mine to 120 4 the night, it's inside, to make sure that mode is working, only diff is the rv fan inside frig blowing air thru evap fins. Had some water bottles inside, forgot to check until late next day, working pretty good, mush ice in the bottles, now to set it outside in the sun in normal top up camped mode, in the sun to see the comparison, then try the propane mode, gonna be interesting. |
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outcaststudios Samba Member
Joined: February 09, 2015 Posts: 1728 Location: Maine
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Posted: Fri May 22, 2015 6:56 am Post subject: |
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they test a thermocouple by applying a specific heat to the tip ,the two metals when heated(or at rest) produce a different electrical potential charge between themselves ,this charge changes as the resistance changes from the addition or removal of heat. the resistance should vary in a certain zone for each different type of thermocouple. _________________ '88Doka JX td
'69 westy
(rip)couple bugs
(rip)three type III"s
(rip) '81 vanagon
a bunch of french stuff,and 9 motorcycles.
https://www.thesamba.com/vw/classifieds/detail.php?id=2573791 |
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Merian Samba Member
Joined: January 04, 2014 Posts: 5212 Location: Orygun
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Posted: Fri May 22, 2015 12:16 pm Post subject: |
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I may have a type K reader lying around somewhere - makes sense it would be a K.
Last edited by Merian on Tue May 26, 2015 12:17 pm; edited 1 time in total |
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Merian Samba Member
Joined: January 04, 2014 Posts: 5212 Location: Orygun
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Posted: Sat May 23, 2015 11:26 am Post subject: |
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also my piezo igniter is lower on the slotted propane gas burner head than is shown in that guys video (but it is for older units) and is also lower than shown in one of the Dometic manuals
it is actually just below the last slot - anyone know if I should move it upwards to the middle of the slots or if it is ok where it is???
(both manuals are silent on this) |
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Merian Samba Member
Joined: January 04, 2014 Posts: 5212 Location: Orygun
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Posted: Tue May 26, 2015 12:18 pm Post subject: |
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2 more Questions:
1. "Gauze in burner head clogged" is one reason listed for not lighting on propane. But what do they mean by "gauze"??
2. how do you remove the small metal one way air valve from the hard metal tube (after the pump) - mine is on there real solid... |
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wyldryce Samba Member
Joined: August 14, 2011 Posts: 83 Location: Annapolis, MD
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Posted: Sun Jul 26, 2015 10:28 am Post subject: Got mine finally running on propane... |
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Have had the 1985 Westy since last fall, and was intrigued/stoked on the possibility of a working fridge as my 1971 Riviera is ice-box only. Have been thwarted on multiple trips though, having it cool well on 120v only to quickly come up to ambient temp running on propane. Always lit easily enough after I tried the tips of blowing out the vent tube and vacuuming out the flue with the shop vac, but still no dice. On hot days this summer it would even get hot enough to trip the stock internal fan, but would never cool.
Yesterday it became to take the tiger by the tail. Yarded out the Dometic, and stumbled upon the "city water fan" idea expressed in multiple threads. Called up the local computer recycler and went and snagged a 21cfm 12v fan for $3. Cut up my go-westy city water door with the dremel, grabbed a aluminum screen patch, and epoxied the whole thing together. I wired it into the switch controlling in the internal muffin fan a prior owner had added.
Combined with a partially clogged jet, which I soaked in a dish of carb cleaner for a half hour then blew out with compressed air, things are finally working as designed!
As an experiment, I lit it on propane, threw a thermometer sensor in there and waited...It was about 7:30pm when I finished last night with a ambient temp of 70. It had knocked off 10 degrees in the first 45min. A good sign. It was about 34 degrees when I went to bed. When I woke this morning, the ambient temp outside was about 55deg and the fridge temp was 55. It's now 3 hours later and the fridge is holding steady at 26 deg.
I've left the fan running the whole time, both interior and the added city-water fan. I was amazed at how much air that thing was moving, and how warm it was, even shortly after lighting off the stove. Since the city water port is directly in front of the chimney, it seems to scavenge a nice amount of air. I did block off the square vent on the left side of the stove with a cardboard plate behind the grate, as I figure it will force air to be drawn from the bottom and top of the fridge, scavenging air from the warmest areas. Thanks again for all the great trailblazing by those on this forum...it's the best! |
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davevickery Samba Member
Joined: July 16, 2005 Posts: 2887 Location: Fort Collins, CO
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Posted: Sat Aug 29, 2015 10:49 am Post subject: |
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I wanted to add this info in case someone is testing and wondering about the wiring on their late model fridge. This relates to the 1990/91 electronic ignition fridges. I had to look it up a couple times, so I figured I would put it out here. I broke my gas switch so I had the thing apart to try fix it.
The wiring for the auto igniter switches is pretty simple. There are 3 sets of wires, 2 for each switch. They are color coded. Right side red wires are for propane operation, middle 2 brown for 12V and left 2 black wires for 120V.
Obviously I swapped mine around since i broke the gas button. Anyone got a switch I can buy/trade for??
They are simple 2 wire independent switches which is good to know if you want to test them. When depressed there should be continuity between the two respective terminals. When you look at the wires connected to the switches it is pretty obvious what it going on. But if your power is not hooked up right, you might think something is wrong with the switches.
THis is the power supply plug. Blue is 12V negative. Brown is positive and used for gas operation for the electonic igniter. Black is positive for 12 voit cooling operation. You only need the power wire connected for whatever operation you are checking.
This other connector isn't importatnt for testing and doesn't need to be hooked up. It goes to the LED panel on the stove and is powered by the millivoltage from the thermocouple to light up the bottom led under the water tank level indicator. It is just useful to know you don't have to do anything with it if you are just testing cooling modes.
The electronic sparker is not pictured but a red wire runs from the gas switch to it and the braided red wire out of it is the piezo sparker and runs down to the burner box. GW sells a replacement for that, but I see others have found cheaper sources. Here is one on amazon for only $28 if yours happens to be bad. It looks like the same one people have bought from Gunzel but it is located in the US and cheaper. http://www.amazon.com/Dometic-2931132019-Re-Igniter/dp/B00BTL7P5M
When you are testing on propane with a portable tank, as I'm sure someone mentioned above, you need a regulator on the hose. Hope this helps someone. |
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davevickery Samba Member
Joined: July 16, 2005 Posts: 2887 Location: Fort Collins, CO
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Posted: Sun Aug 30, 2015 3:50 pm Post subject: |
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So I have been testing this fridge before I decide if I want to install it. It cooled quickly. Ambient temp in the house are 75 and it is down to 40 in a couple hours. After 5 hours or so it is around 37-38 (I measure with a remote thermostat on the shelf below the fins with fridge empty).
This sounds good but I know with the cabinet will become totally heat soaked on a hot day and the fridge temps will be a lot hotter. I notice the little fan on the back didn't work, so I put a temporary CPU fan in back and ran it for an hour. Temps drop to around 30 at which point I turn the dial back and it is cycling around 37 and is still there in the morning.
I wanted to test it under stress during the heat of the day so I put 2 towels over the back of it, blocking off most of the fresh air and have it outside in the sun. It was a high around 90 today. By the afternoon it reached 62 degrees with the temp on the table at the bottom of the fridge (under the towels) reading 116. At that point, I hooked up the CPU fan again and watched the interior temp drop from 62 to 42 in an hour and a half. Here in lies the secret to Dometic fridge functioning. You have to have a way to evacuate the hot air out from behind the cabinet. I think on prior fridges that didn't work well, the little fan back there wasn't coming on. And fridges that worked well, I do recall hearing the fan sometimes.
I think an interior fan is a waste of time. I think added insulation is far less important than rear heat control and I don't think the ambient temps of 90-95 degrees are really the problem. The air behind the fridge is way above 90 degrees whenever the fridge is running (the fins are warm/hot to the touch) and I bet the compartment back there is 200 degrees or more with the exhaust stack just pouring out heat behind the fridge. From what I could find the fan is designed to come on at 130 degrees. So I think the key is to try to keep the rear of the fridge compartment under 130 degrees. I think the other mods people do is just guessing at what might make a difference and are far less important. Dometic put a fan in the back for a reason, and not one inside. I bet half the fridges out there have a frozen fan motor like this fridge did.
I know people have explored different ways of mounting aux fans or just upgraded fans in the same location. That is my next experiment, seeing if one good CPU fan (35 cfm, .1 amps) in the stock location is enough or if a second exhaust fan is worthwhile. They only cost $5-6 on amazon so no big deal if two are necessary. http://www.amazon.com/Cooler-Master-Bearing-Coolin...r+fan+80mm
By the way, I know I am putting a lot of time into an old marginal fridge. I'm just experimenting for fun. If I have to get a truckfridge and solar, I am fine with that but I have some free time now while my van is at the shop.
It seems to have settled out at 40 degrees and 100 degrees at the bottom of the fridge under the towels. I wonder if my towels are a good simulation? But good enough I think to try it in the van with an upgraded fan.
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kamzcab86 Samba Moderator
Joined: July 26, 2008 Posts: 7893 Location: Arizona
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Posted: Sun Aug 30, 2015 6:18 pm Post subject: |
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davevickery wrote: |
At that point, I hooked up the CPU fan again and watched the interior temp drop from 62 to 42 in an hour and a half. Here in lies the secret to Dometic fridge functioning. |
That's pretty good results and am glad to hear it because... see below.
davevickery wrote: |
I think on prior fridges that didn't work well, the little fan back there wasn't coming on. And fridges that worked well, I do recall hearing the fan sometimes. |
The stock fan is definitely audible... it's especially noisy before it croaks.
davevickery wrote: |
I bet half the fridges out there have a frozen fan motor like this fridge did. |
My Dometic's fan seized up the first the night of a recent trip. I don't know about anyone else's Dometic, but because of the fan seizing, the fridge fan/faucet circuit fuse blew every time the fan was signaled to kick on. Can't say whether the OEM fuse would blow because I routed the wires through a Blue Seas panel. Thank goodness for the ARB!
davevickery wrote: |
I know people have explored different ways of mounting aux fans or just upgraded fans in the same location. That is my next experiment, seeing if one good CPU fan (35 cfm, .1 amps) in the stock location is enough or if a second exhaust fan is worthwhile. |
Ironically, I just went to Fry's Electronics today to pick up a 120mm CPU fan (pulling my fridge over Labor Day). The fan I got is on par with the one GoWesty sells, producing 81.5 cfm and drawing 0.3 amps (23 decibels). While it's relatively lightweight, I'll be making brackets like Rodknock did: http://www.thesamba.com/vw/forum/viewtopic.php?t=177258 . _________________ ~Kamz
1986 Cabriolet: www.Cabby-Info.com
1990 Vanagon Westfalia: Old Blue's Blog
2016 Golf GTI S
"Real knowledge is to know the extent of one's ignorance." - 孔子 |
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kamzcab86 Samba Moderator
Joined: July 26, 2008 Posts: 7893 Location: Arizona
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Posted: Tue Sep 15, 2015 11:38 am Post subject: |
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Follow-up to ^that post. Pulled the fridge out last week. Cleaned up the exterior (dirt, dog hair), lubed the air pump, and replaced the dead OEM fan (which also had hair wrapped around it ):
A couple of brackets were made for it. Instead of splicing wires, as GW has you do, I used a 4-slot (2 pin) Molex connector after crimping a female disconnect onto each wire (one regular size, one small size for the temp sensor) so that it plugs right into the stock wiring (plug and play for potential future fan replacements):
(Fan was rotated after the pic was taken; wiring now runs up the side of the fridge.)
The wiring was long enough to put the Molex connector near the propane line. Since Molex connectors are usually piggyback types, this allowed me to mount a second fan at the cabinet opening:
Results after running overnight on AC power:
Van interior: 89°
Fridge temp: 49°
Fridge is now 40° below ambient (with summer temps), whereas before it only got to 30° below ambient. Pretty pleased with the results.
I did not do the lay-it-on-its-side dance because my fridge still fires up without issue... i.e. I didn't care to "fix" what wasn't broken.
In case anyone is interested, this is the fan: http://frys.com/product/8070814 . _________________ ~Kamz
1986 Cabriolet: www.Cabby-Info.com
1990 Vanagon Westfalia: Old Blue's Blog
2016 Golf GTI S
"Real knowledge is to know the extent of one's ignorance." - 孔子 |
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Merian Samba Member
Joined: January 04, 2014 Posts: 5212 Location: Orygun
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Posted: Tue Sep 15, 2015 1:32 pm Post subject: |
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Merian wrote: |
also my piezo igniter is lower on the slotted propane gas burner head than is shown in that guys video (but it is for older units) and is also lower than shown in one of the Dometic manuals
it is actually just below the last slot - anyone know if I should move it upwards to the middle of the slots or if it is ok where it is???
(both manuals are silent on this) |
any ideas? |
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davevickery Samba Member
Joined: July 16, 2005 Posts: 2887 Location: Fort Collins, CO
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Posted: Tue Sep 15, 2015 1:57 pm Post subject: |
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"The distance between the tip of the electrode and the burner, known as the spark gap should be 3/16 of an inch. A greater distance will create a slow spark causing the light to blink. A lesser distance will create a fast spark that may not light the burner."
http://www.westfaliat3.info/General_Dometic_Refr_Service_Manual.pdf |
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57 Zwitter? Samba Member
Joined: November 07, 2003 Posts: 418 Location: Boston, Mass.
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Posted: Wed Sep 16, 2015 3:50 am Post subject: |
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to kamzcab86, I understand mounting the fan below the black cooling fins on the back of the fridge, but why did you mount another fan above the outlet inside the Rh cabinet? I thought the best place for the 2nd fan was on the city water door so the heat would be pushed out of the van. Ready to order fans for my 85 westy and want to be sure I am following what has worked for others. |
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kamzcab86 Samba Moderator
Joined: July 26, 2008 Posts: 7893 Location: Arizona
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Posted: Wed Sep 16, 2015 10:58 am Post subject: |
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57 Zwitter? wrote: |
to kamzcab86, I understand mounting the fan below the black cooling fins on the back of the fridge, but why did you mount another fan above the outlet inside the Rh cabinet? I thought the best place for the 2nd fan was on the city water door so the heat would be pushed out of the van. Ready to order fans for my 85 westy and want to be sure I am following what has worked for others. |
I bought a second fan thinking I'd mount it on the back of the fridge somewhere. A second fan will fit under the upper-most set of fins, and a second L-bracket was made, but opted not to install the second fan due primarily to not having another support bracket (not that it needs one, but I prefer to go the overkill route).
Upon reinstalling the fridge, I looked at that cabinet opening and presumed it was the same size as the 120mm fan... and it was. So, as an experiment I set the fan on the stove gas line, plugged it in, and left it overnight. Seeing the 40° temp differential, I then ziptied the fan for a more "permanent" install. With the OEM fan, heat would simply rise out of the kitchen vents; now, heated air actually blows out of the vents. I don't know if anyone else has ever installed a second cooling fan, but, for my fridge, it seems to like it.
I understand the concept of turning the city hookup into an exhaust fan, but, to me, it's like my old (Windows XP-old!) desktop CPU: It came with two 80mm fans; one blows directly onto the processor, the other exhausts air out the back. Heat builds up like no one's business and the CPU starts slowing down. When I replaced the power module, I left the side panel off... heat still built up (it sits inside an open desk cabinet). I installed a 120mm fan at the bottom, blowing up, and reversed the rear 80mm fan; now, instead of exhausting a minimal amount of heat out the back and side, the cool house air is being blown in. CPU now runs cooler than it ever has and doesn't slow down after running for hours.
While exhausting heat is good, maximizing airflow seems to be a better method, especially when you understand how absorption fridges, as these Dometics are, work: "Heat is generated in the absorber by the process of absorption. This heat must be dissipated into the surrounding air. Heat must also be dissipated from the condenser in order to cool the ammonia vapor sufficiently for it to liquefy. Free air circulation is therefore necessary over the absorber and condenser." http://vintageservelrefrigerators.8k.com/HowItWorks.html
When the van is closed up and parked out in the sun, particularly in the summer, the absorption-generated heat is being dissipated into heat. This is where the exhaust fan will come into play: You're exhausting that heat build-up to the outside. So, really, two cooling fans and one exhaust fan might be the best set-up. I turned my city hookup into a solar connection, so an exhaust fan there is not possible for my van (I leave the screened kitchen window open, depending on where the van is parked).
Right or wrong, ^^that's my amateur scientific reasoning. _________________ ~Kamz
1986 Cabriolet: www.Cabby-Info.com
1990 Vanagon Westfalia: Old Blue's Blog
2016 Golf GTI S
"Real knowledge is to know the extent of one's ignorance." - 孔子 |
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spitsnrovers Samba Member
Joined: December 17, 2005 Posts: 924 Location: Calgary, Canada
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Posted: Wed Sep 16, 2015 11:29 am Post subject: |
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Re your comment about not using two fans - here is my version of that. Sort opf the city water hookup but different.
http://www.griffco.ca/interest/vw/vwfridgevent.htm _________________ '88 VW Westfalia
'75 Triumph Spitfire 1500 |
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davevickery Samba Member
Joined: July 16, 2005 Posts: 2887 Location: Fort Collins, CO
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Posted: Wed Sep 16, 2015 11:31 am Post subject: |
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kamzcab86 wrote: |
While exhausting heat is good, maximizing airflow seems to be a better method, especially when you understand how absorption fridges, as these Dometics are, work: "Heat is generated in the absorber by the process of absorption. This heat must be dissipated into the surrounding air. Heat must also be dissipated from the condenser in order to cool the ammonia vapor sufficiently for it to liquefy. Free air circulation is therefore necessary over the absorber and condenser." http://vintageservelrefrigerators.8k.com/HowItWorks.html
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I think this might be a key point. I had said previously that I thought getting the heat out from behind the cabinet seemed to be the key, but it is possible that just getting the heat away from the lower fins and condenser is the most important thing. I think there needs to be a temperature differential to keep the asborption process going and a big fan blowing right on the lower coils may be the best improvement. On a prior nearly mint condition fridge, when the fan was broken, the fridge seemed to all but stop working in the hot afternoon sun.
After looking at Kamz fan, I decided to buy a better one and went with a 120mm 74 cfm unit (SilenX brand). In the past I glued a smaller 80mm fan right onto the vent on the left side of the fridge with a separate switch. I had it set to blow in. It helped just by itself during those brutal afternoons, but I can't compare it to anything. It made a fridge I was considering removing into an acceptable summer fridge again. If I add a second fan it would be in that same spot with a manual switch.
BTW, nice job on those brackets. I used silicone and a couple random bent pieces of metal, but only I know what it looks like. |
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kamzcab86 Samba Moderator
Joined: July 26, 2008 Posts: 7893 Location: Arizona
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Posted: Wed Sep 16, 2015 1:52 pm Post subject: |
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davevickery wrote: |
I think this might be a key point. I had said previously that I thought getting the heat out from behind the cabinet seemed to be the key, but it is possible that just getting the heat away from the lower fins and condenser is the most important thing. I think there needs to be a temperature differential to keep the asborption process going and a big fan blowing right on the lower coils may be the best improvement. |
Exactly. Another quote from the link: "Air circulating over the fins of the condenser removes heat from the ammonia vapor to cause it to condense to liquid ammonia in which state it flows into the evaporator."
No doubt the exhaust fan mods are doing their jobs at removing heat, but for the fridge to work at peak efficiency, especially in an enclosed space, max airflow over the fins is, IMHO, what you're after (simply replacing the anemic stock fan with a high cfm computer fan is a big improvement). That's the reason I added the second cooling fan. I may add a switch to it so I can easily shut if off during winter trips. _________________ ~Kamz
1986 Cabriolet: www.Cabby-Info.com
1990 Vanagon Westfalia: Old Blue's Blog
2016 Golf GTI S
"Real knowledge is to know the extent of one's ignorance." - 孔子 |
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57 Zwitter? Samba Member
Joined: November 07, 2003 Posts: 418 Location: Boston, Mass.
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Posted: Thu Sep 17, 2015 10:15 am Post subject: |
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Where do I find the propane "JET" that was mentioned needing cleaning? I disconnected my propane lines on top of the fridge and just found big copper pipes, no reducer at all. |
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dobryan Samba Member
Joined: March 24, 2006 Posts: 16474 Location: Brookeville, MD
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