Can the gas orifice be changed on a fridge

[Outsider]

I want to give good info here in case someone needs it for reference later. Sorry for the length.


OK, folks, it appears I have proven that the problem is in the chimney/heating area. I borrowed an IR temperature gun from a friend and have been able to determine that on average the main pipe/tube coming out of the chimney runs 40 degrees cooler when on gas than when on electric. I placed a white dot on the tube at two locations about 2 & 3 inches above the chimney for spotting accuracy and found that the lower dot runs at a constant average of 243 degrees and the upper averages 210 degrees on electric but only 200 and 175 on gas. I took 12 readings over a period of 7 hours after the system had already been hot on electric for 12 hours.


Next step is to find a way to get an accurate measurement of the vacuum/pressure on the gas line just before the orifice. I found a gauge that I can purchase but am waiting on a response from someone that knows more about calculating the 11”WC value that must be achieved.

This is one of the gauges that I found: https://www.walmart.com/ip/Harupink-...ter2/634075661 but it reads in “HG and bars of atmospheric pressure.


I hope someone with accurate knowledge/experience will reply here or send me a private message. I do not have experience in gas but obviously I'm not a rookie in tools and elector/mechanical problems.


Thanks for your help.

[babock]

Originally Posted by Outsider

This is one of the gauges that I found: https://www.walmart.com/ip/Harupink-...ter2/634075661 but it reads in “HG and bars of atmospheric pressure.

You do not want that type of gauge. You need something that measures 11" WC.

https://smile.amazon.com/Manometer-R...5880201&sr=8-5

[Scrapper]

Originally Posted by babock

You do not want that type of gauge. You need something that measures 11" WC.

https://smile.amazon.com/Manometer-R...5880201&sr=8-5

Not to mention OP needs to read pressure, not vacuum which is what the gauge in his link is for.

[Bama Rambler]

As mentioned above you need a gauge that reads inches of water pressure.
You can buy traditional type gauges that read inches of water, but I'd just get the one babock linked to.

I'm surprised that the service centers didn't mention testing the system gas pressure.

[Stank Bait]

Pressure regulator may be set wrong (low). Maybe just replace the changeover regulator valve. If no change then you have a spare.



Or if brave...try this

https://youtu.be/gLb0l5a96s0

[eric1514]

Look at page 20 of the service manual that was linked, specifically the section titled 7.5 FLUE BAFFLE. Make sure you have one and that it is installed properly.

The section says "The flue baffle ( spiral baffle ) is a twisted piece of metal that hangs in the flue tube to slow the heat from the flame to the proper location on the cooling unit. If the flue baffle is too high or low the heat will not be transferred to the cooling unit properly"

[Outsider]

Thanks Eric. That's the next step. I'll have to pull the fridge completely out to check that so I'm probably going to order a meter/tester to check the gas pressure first. It will take a few days because I'll have to order the meter.

[Outsider]

Stank Bait, were you talking about the main gas line regulator right off of the tank or is there another regulator somewhere for the fridge when you said this: "Pressure regulator may be set wrong (low). Maybe just replace the changeover regulator valve."


Also, would that regulator have to come from Forest River/Coachmen?



Thanks.

[CHICKDOE]

rather than ordering meters and new regulators try to hook the refrigerator up to a tank and regulator that you 'borrow' from you barbeque. you may need an adapter but i'm sure you can get it at any hardware store. that way you will be running your refrigerator off a tank / regulator that provides the required gas pressure (assuming it worked ok on the barbeque).

[Outsider]

So you are pretty sure the regulator on my separate, free-standing backyard bbq grill is the same pressure? If so I'll take a look at trying that.


And just more info for everyone here, the furnace, 2-burner gas stove top and water heater all seem to work fine on this same camper regulator.


Thanks.

[CHICKDOE]

yes the 'standard' is 11" WC (water column) and that is what almost all regulators regulate to.

[Outsider]

Just a quick update for those following this issue. I connected my BBQ grill regulator and tank to the gas line connection for the fridge (as suggested by ChickDoe) and the difference in the heat being generated at the out-going coolant tube at the top of the chimney was significant.


Using an IR heat gun I found the following:
Temp when connected to the original gas line: 200 degrees.
Temp when connected to shore electric: 243 degrees.
Temp when connected to the BBQ regulator and tank: 260 degrees.


I am in the process of "adjusting" the original regulator to attain a "cooking" temp of approx ~243 degrees like that when connected to shore electric since that is when the fridge works best. I will post my final results later.


Thanks to everyone for their input.

[Bama Rambler]

I wouldn't adjust the RV's propane regulator based on temp produced by the fridge. It needs to be adjusted based on system pressure. By trying to adjust it based on temp from one appliance you may seriously over-pressure the system and cause other issues not the least of which may be a fire.

PLEASE DON'T DO IT.

[babock]

Originally Posted by Bama Rambler

I wouldn't adjust the RV's propane regulator based on temp produced by the fridge. It needs to be adjusted based on system pressure. By trying to adjust it based on temp from one appliance you may seriously over-pressure the system and cause other issues not the least of which may be a fire.

PLEASE DON'T DO IT.

XXXX2!!!

[Outsider]

Thanks for pointing that out guys, and of course that will be the conclusion of all this. I simply do not have a meter yet. Sorry I failed to make that clear.

[Stank Bait]

Just replace with a new regulator. Cheap and safe solution. Can just get the same one online or RV place so all fits the same.



Note that if you want to use teflon tape on the threads that there is a special teflon tape for propane connections. Lowes and HD have it.

[Outsider]

Bama Rambler, babock, RVDoctor, Scrapper, and others,


I have a manometer on order as suggested to check that the actual gas pressure at the fridge is set to 11”WC but not sure of the easiest way to accomplish that.

If you look at the pic I will attach, you will see the left-most red arrow marks the incoming gas line. That is probably the easiest access point and I’ve had this line disconnected during the testing process but what type nipple or connector do I need in order to hook up there? The end of the gas line is a female connector there, not sure of the size.

The next arrow to the right is the manual gas cut-off valve directly under the relay that has to trip in order for gas to flow.

The next arrow to the right is an access point to this assembly where something else could be attached. But, again, what type nipple or connector do I need in order to hook up there? Plus there will be no pressure here unless the relay is activated and the nozzle to the right is capped in some way. (The igniter would be firing at this point as well. That should not be a problem as it should only take 5 sec to get a reading with the manometer.)

The final arrow to the right is the nozzle/orifice/gas outlet which could also be removed and replaced with a nipple or connector as well. But again, the system would have to be calling for gas, have the relay energized and the igniter would be firing.

The first option above seems to be the best way to go but I will need a nipple or connector of some type for the manometer hose to attach to.

Am I overlooking something simpler here?

[CHICKDOE]

yes there is a simpler way! the pressure (11"wc) is constant throughout the gas system. you can measure that pressure at any convenient place. it doesn't have to be at the water heater. for example, if you have a quick disconnect you can remove it and attach the manometer in its place. or unscrew the output hose from the regulator and screw the manometer into the output side of the regulator. just measure the pressure when the system is at rest, ie no gas flowing.

[Stank Bait]

https://www.youtube.com/watch?v=i4ROWQu2Xcs

Do it yourself manometer

[Bama Rambler]

Chickdoe is correct. Any place you can access the system is fine to test the pressure.

Most of those manometers come with some plastic tubing. at no more pressure than we're talking about you can easily hold the tubing against the pressure.

I would probably remove the tubing nut on the incoming line to the fridge (leftmost arrow) and just hold the tubing against the gas line while someone turned on the gas and test the pressure there.