Author Topic: Propane fridge venting  (Read 788 times)

0 Members and 1 Guest are viewing this topic.

Offline Beavers

  • Senior Member
  • ****
  • Posts: 388
  • Location: Nebraska
    • 12x16 House Project
Propane fridge venting
« on: April 21, 2018, 09:10:32 PM »
Did a search for this and was surprised to not find anything on here. ???

When we lived in our cabin before kids, we just used a cooler and ice to keep a few things cold. Now that we are planning on moving back into the cabin with a couple of boys that require feeding every 30 minutes the cooler isn't going to cut itl :)

It was painful...but I picked up a Dometic 2652 propane fridge today for $1300.  It's crazy how expensive those things are.  Reading the manual and the hookup and venting is a little more involved than I thought.

I've read that they don't work very well in cold temps.  It gets cold here so I'm thinking of having the air intake draw from the enclosed area under the house where the air is warmer in the winter and cooler in the summer. I can't vent the exhaust through the roof so it's going have to be a sidewall exhaust. I was thinking of using class b pipe and having a short chimney on the exterior. How much draw do these fridges need?  Any thoughts or tips on propane fridge venting?

Offline Redoverfarm

  • Journeyman
  • *****
  • Posts: 6,760
  • Applachian Mtns, West Virginia
Re: Propane fridge venting
« Reply #1 on: April 22, 2018, 01:49:56 AM »
Maybe Mountain Don will join in but he posted information about his refrigator and the venting that he had done.  The biggest problem I have is the moisture emitted by the exhaust. They make kits for both intake and exhaust.
« Last Edit: April 22, 2018, 06:50:52 AM by Redoverfarm »

Offline MountainDon

  • Administrator
  • Journeyman
  • *****
  • Posts: 16,706
  • Jemez Mountains, NM; that's pronounced HEY-mess
    • My 15.75 x 30 Jemez Cabin
Re: Propane fridge venting
« Reply #2 on: April 22, 2018, 04:58:52 AM »
I'll get back to this. I don't like poking at a small screen for longish explanations. (At cabin for a few days. Fridge running good)
Just because something has been done and has not failed, doesn’t mean it is good design.

Offline Beavers

  • Senior Member
  • ****
  • Posts: 388
  • Location: Nebraska
    • 12x16 House Project
Re: Propane fridge venting
« Reply #3 on: April 22, 2018, 07:39:03 AM »
Red, the only vent kit I can find is for the 4 series of Dometic fridges or the plastic RV vent covers. Where did you get yours?

Offline MountainDon

  • Administrator
  • Journeyman
  • *****
  • Posts: 16,706
  • Jemez Mountains, NM; that's pronounced HEY-mess
    • My 15.75 x 30 Jemez Cabin
Re: Propane fridge venting
« Reply #4 on: April 22, 2018, 08:31:47 AM »
John & I both have Dometic / Servel RGE400's.  I see it has been redesigned with the controls up top . That would be nice!  https://www.dometic.com/en-us/us/products/food-and-beverage/refrigeration/refrigerators/dometic-servel-rge400-_-47218

I have taken a few pictures of how I built a vent system. It could be used for the fridge you have. We'll be home sometime Monday and I'll post them then.
Just because something has been done and has not failed, doesn’t mean it is good design.

Offline Redoverfarm

  • Journeyman
  • *****
  • Posts: 6,760
  • Applachian Mtns, West Virginia
Re: Propane fridge venting
« Reply #5 on: April 22, 2018, 10:02:11 AM »
Red, the only vent kit I can find is for the 4 series of Dometic fridges or the plastic RV vent covers. Where did you get yours?

I don’t have either yet.  The intake just draws off the interior.  My biggest problem is the exhaust emitting moisture.  I will just use a piece of stainless flex to come off the stack and route to the interior.  Will probably design a cover on the exterior to prevent blow back air .  Just not high on my bucket list right now.

Offline MountainDon

  • Administrator
  • Journeyman
  • *****
  • Posts: 16,706
  • Jemez Mountains, NM; that's pronounced HEY-mess
    • My 15.75 x 30 Jemez Cabin
Re: Propane fridge venting
« Reply #6 on: April 23, 2018, 02:20:23 PM »
Originally I bought the vent kit that thenaturalhome.com sells. Here's an installation drawing for reference.



I had issues with it. A sudden gust of wind from the south (the vents are in the south wall) would blow out the pilot light. We could not live with that. So I rethought what was needed and borrowed from the way propane fridges are installed in RV's.

I built a "chase" on the interior side of the kitchen wall. The fridge stands on the floor like normal and is pushed back against the chase, or boxed in area.



The area directly behind the fridge is open fronted. I added a right side flange to the fridge back to make sealing against foam strip better. The left side is sealed more or less with a section of pipe insulation pressed into the space between the wall and the fridge side.

The exterior has an upper and a lower vent cut through the wall.




The patch just below the upper vent grill is from the experiment using the purchased vent kit. Someday I should touch up the paint. That picture shows the grills with aluminum foil under the vent screen. I did that as over the winter we generally do not use the fridge for the 2 days at a time once a month. The foil blocks wind and in my mind keeps the cabin warmer.

Next is a picture looking up the chase from the bottom vent position. I retained a short extension on the exhaust stack from the kit I tried out.



The following picture if looking down the chase from the top vent.



The exhaust extension goes as high as the condenser coil. I wanted to get the hot exhaust up past the condenser as the condenser gets hot enough as the system cools the interior of the fridge. I had to stop there as the condenser slides in under the upper boarded up section of the chase.

The first image shows a "hatch" on the side of the wood chase side. That is an access port for the on-off gas valve.





The first image also shows a hinged panel at the chase top. Here's the story behind that.  When the fridge is to be used and the exterior wall vents are not blocked off, that interior panel is left closed as pictured. A section of the pipe insulation is pushed under the lower front of the refrigerator. That seals the chase airspace from the cabin interior. Air for combustion and cooling enters from the outside lower vent and exits the upper exterior wall vent. I installed the lower vent above the height of the burner (floor level) to avoid wind gusts directly blowing on the burner box. The burner has never flamed out in the years since I made this setup.

I the winter, with the exterior wall vents closed off the upper inside panel can be flipped open. With the pipe insulation removed from under the lower front of the fridge air for combustion and cooling enters under the front edge. Exhaust then exits the chase along with the warmed air from cooling the condenser fins. That way we retain that heat inside. We have two CO monitors. They should be replaced every 5 years orso, so one is now 4 years old and the other only 2. They have digital readouts and have never 'alarmed', never shown any higher CO level than 20 ppm. That returned to zero after cleaning the burner box (a few spider webs). If left unused for a period of time spiders sometimes spin webs in the confined space. neighbors had a very close call traced to their propane fridge and spider webs.

The cabin interior stays notably cooler in warm weather when the system is set to vent to the outside. That alone could be worth the effort of making an exterior venting system. In the colder weather, it is not unusual to overheat with the wood stove than to be not warm enough so we mostly do not vent to the interior unless I block the vents to ward off the cold wind driven drafts. Those are mostly felt on the tile floor in the vicinity of the fridge, so aren't too bad.

We are blessed or cursed, depending on how one looks at it, by a low humidity environment. As a result, I can not say we have ever had a problem with too much interior humidity most of the time. High humidity comes with the short monsoon season and then usually only on days when it does rain. Winter is a struggle to maintain enough humidity for comfort.

Anyhow, there it is. Any questions, comments, just jump into the conversation.


Just because something has been done and has not failed, doesn’t mean it is good design.

Offline Beavers

  • Senior Member
  • ****
  • Posts: 388
  • Location: Nebraska
    • 12x16 House Project
Re: Propane fridge venting
« Reply #7 on: April 23, 2018, 06:04:23 PM »
Thanks for the pics and very detailed response Don.   My fridge isn't finished on the sides so I have to build a cabinet anyway. I had something vaguely in mind like what you did.

I'm sure I'll have some more questions after reading your post a few more times and digesting all the info. Thanks again [cool]

Offline MountainDon

  • Administrator
  • Journeyman
  • *****
  • Posts: 16,706
  • Jemez Mountains, NM; that's pronounced HEY-mess
    • My 15.75 x 30 Jemez Cabin
Re: Propane fridge venting
« Reply #8 on: April 24, 2018, 05:54:09 AM »
I had meant to add something but forgot.

With propane fridges, there are two different heat sources; heat that must be moved someplace. The propane burner that drives the system produces heat and possibly can also produce CO. The CO is the main reason for why a propane fridge should be vented to the exterior. Heat is also produced, or at least given off by the condenser coil/fins. That's the part located near the upper backside of the fridge. That heat of course is coming from the interior of the fridge. Electric fridges have this heat output too.

Propane fueled refrigerator efficiency can be increased it the heat from the burner can be kept away from the condenser. The cooler the air flowing through the condenser fins the better the heat is transferred from the fins to the air. Cooling efficiency can be enhanced by forcing the air through the fins.  If you install a baffle between the condenser fins and the wall behind the fridge that will force all the rising air behind the fridge through the fins. With no baffle much of the air that flows bottom to top behind the fridge can miss the fins.

I made the fridge in our RV work much better with such a baffle. When I made this chase for the cabin fridge I did not. Time was short and I wanted to get the exhaust out of the cabin quick. I figured I might go back and make a baffle someday. Well, that fridge has no trouble making ice or keeping ice cream frozen hard enough, too hard actually, to eat without a defrost period. So I have never had incentive enough to return to building a baffle. However, that did make a big difference with our RV fridge and the fridge in my brother in laws RV.

Just thought I'd mention that.
Just because something has been done and has not failed, doesn’t mean it is good design.

Offline DaveOrr

  • Senior Member
  • ****
  • Posts: 221
  • Living In The Land Of The Midnight Sun
    • The Arctic Angler
Re: Propane fridge venting
« Reply #9 on: April 25, 2018, 03:27:29 PM »
Unique Off-Grid Fridges are available in non-vented and direct vent models.
The DV models need to be on an outside wall for the venting.


https://propanedepot.ca/products/off-grid-fridges/
Dave's Arctic Cabin: www.anglersparadise.ca

Offline MountainDon

  • Administrator
  • Journeyman
  • *****
  • Posts: 16,706
  • Jemez Mountains, NM; that's pronounced HEY-mess
    • My 15.75 x 30 Jemez Cabin
Re: Propane fridge venting
« Reply #10 on: April 25, 2018, 04:07:02 PM »
Canada has more stringent fuel burning appliance rules than the US. Venting rules have actually gone more towards more locations allowing non vented appliances than being more restrictive. I'm not sure that is a good thing. The pessimist inside me thinks big businesses throw money at the legislators to gain influence. When we were shopping for a cabin fridge 10 years ago there were not any that came with venting.

Today though, I would install a larger solar array and go electric. There are getting to be more and more choices of very energy efficient refrigerators. The ones to look for use "digital inverter compressors". They are readily sorted out from the pack by looking for the big sticker that proclaims 10 year compressor warranty. Their compressors have no big start up surge. They run at variable sppeds, from near 0 rpm on some to maybe 4000 rpm or a little higher. They hold the set temperature much closer than the all on or all off type we are used to. In most of the balance of the world they have been commonplace for several years. LG and Samsung have them I know.
Just because something has been done and has not failed, doesn’t mean it is good design.

Offline DaveOrr

  • Senior Member
  • ****
  • Posts: 221
  • Living In The Land Of The Midnight Sun
    • The Arctic Angler
Re: Propane fridge venting
« Reply #11 on: April 27, 2018, 05:00:46 PM »
Today though, I would install a larger solar array and go electric.

That's the way I'm going.
Cost on them is way below that of a good full size propane unit.

Solar system is going to cost me in the 15-20K range for my place.
Gonna be living there full time and have all the amenities.
:)
Dave's Arctic Cabin: www.anglersparadise.ca

Offline Dave Sparks

  • Senior Member
  • ****
  • Posts: 707
  • Offgrid Solar
    • Offgrid Solar
Re: Propane fridge venting
« Reply #12 on: April 28, 2018, 05:25:01 AM »
Another thing that I suggest to clients is if you have a cabinet above the refrigerator like many kitchens do, is to build a 2" deep notch in the back, the width of the cabinet.

This space against the wall going up to the ceiling will allow the warm air from any type of refrigerator to not be trapped behind the unit as Don was writing. The notch will be hardly noticed and can really help in summer.



"we go where the power lines don't"

 

Templates: 5: index (default), Ads (default), Portal (default), Display (default), GenericControls (default).
Sub templates: 12: init, html_above, adsheaders_above, body_above, adsindex_above, portal_above, main, portal_below, adsindex_below, body_below, adsheaders_below, html_below.
Language files: 3: SPortal.english (default), index+Modifications.english (default), Ads.english (default).
Style sheets: 1: portal (default).
Files included: 38 - 1121KB. (show)
Cache hits: 13: 0.00251s for 40,609 bytes (show)
Queries used: 22.

[Show Queries]