Norcold Fridge Model N305R not cooling bottom

[mtnman1989]

My 2017 Norcold Fridge Model N305R is not cooling the bottom of the fridge. The freezer is below zero but the bottom of fridge is not getting cold. Same on Electric or LP gas. I have a thermostor that is factor set and not removable. I think I might could pry it loose though. The fridge has worked fine until this past week. Are there any recommendations on how to fix the problem?

[mtnman1989]

Sunday July 23rd, 4 days later. Turn fridge on LP yesterday and it was 33 degrees this morning, still working!

[mtnman1989]

Wed July 19th 5:30 am 15 hours later and the fridge is 30 degrees, FIXED! I think the compressed air was all it needed.

[mtnman1989]

Update:
I turn the 120 electric off and did the non scientific regulator test, it did fine. I left the fridge on LP gas after the LP regulator test. It has been on LP gas for 5 hours and the fridge temperature increased just 3 degrees from 27 degrees to 30 degrees! I think it is fine, what's your opinion?

[mtnman1989]

I figured you were a tech, lucky to have someone like you on the forum!

[dougrainer]

mtnman1989 wrote:
How did you learn all this fridge info, were you a tech or do like I do and learn from personal experience?

I am a Master Certified RV technician with 44 years experience. TRUST ME when I tell you the details on how to troubleshoot and measure temp. You call up RVP(Coleman)/Dometic/Norcold and tell them an IR measurement, they will laugh at you. I do NOT know the difference between the 3 model numbers. There IS a difference between the 3 way and 2 way by the letter at the end of the N305. You NEED a LP pressure test. You will be spinning your wheels if it works fine on 120 but you have a problem with the LP without the pressure test. A not scientific way to test your LP regulator is to turn of the refer on LP. Then light the range burners on full. LIGHT the water Heater and furnace. Watch the Range burners. If the flames pulsate or diminish when you run the water heater and furnace your LP regulator is bad and needs replaced. You can also remove the LP burner and remove the orifice and blow it out. Is the refer in a slide room? Doug

[mtnman1989]

How did you learn all this fridge info, were you a tech or do like I do and learn from personal experience?

[mtnman1989]

I forgot to mention that the black pipe going into the tube temp is just under 200 degrees.

[mtnman1989]

There is NO WAY a RV refer will get to -10 degrees.

That was the temp on the back wall of refer with the IR THERMOMETER. We only have one refer THERMOMETER and it is in the food compartment.

The THERMOMETER in the food, lower fridge compartment has staying dead even on 28 degrees all day!

I don't know if it matters but our Norcold Model number is N306R instead of the N305R I posted earlier. Do you know what the difference is between the two models?

I did blow out the flue tube earlier with the air hose, compressed air.

I don't have anything to measure the LP pressure(11.5), but the range burners are working as usual.

I am about ready to try the fridge on LP again?

Anything else I need to do?

[dougrainer]

There is NO WAY a RV refer will get to -10 degrees. -10 would be 10 degrees BELOW 0. WILL NEVER HAPPEN. YES, a BAD cooling unit will freeze water to ice. Freezing is 32 degrees and below. This type problem is common when a seller is selling his RV with a BAD refer. They show a cup of water frozen in the freezer, but it is NOT at 10 degrees or below. The buyer thinks the refer is OK but in reality it is a bad cooling unit. I use a standard digital thermometer laying in the freezer to get the correct temp of the freezer and then a same type thermometer in the glass of water in the lower refer to get THAT temp. So, when dry camping make sure the refer vents are on the backside of the daily sun. Doug

PS, depending on your answers, your cooling unit appears to be fine

[dougrainer]

LP pressure is suspect if you have those temps on 120. Also dirty burner flue tube. Blow out with compressed air. You do operate the LP on HI setting? The service manual is adamant. NO FLAME change height unlike bypass LP tstats. So, if you get a flame height change, your LP tstat may be bad after verifying LP pressure(11.5). YES, an IR will work for the freezer wall temp. Your 30 degrees, was that with the IR and what did you point it at when you took that 30 degree temp? Doug

[mtnman1989]

OK, here is an update.

When we got home from dry camping yesterday morning, we plugged the camper into 110 outlet and turn the refer on. This morning everything is working perfect, the freezer is minus 10 degrees and the cooling bottom is 30 degrees.

What do you want me to check next?

Do you think it could be the tstat for LP?

I assume that I have an LP problem only? I was thinking about turning off the LP tanks and disconnecting my LP line at both ends and blowing it out. If that don't fix it, I may need to replace my regulator?

We looked for a cooling fan and there is no cooling fan nor has there every been one. Which is a good thing since 90% of our camping is dry camping without electric.

Just so you know, while dry camping last week I disconnected my 12 volt batteries and the LP to the refer stayed on.
Thanks!

[mtnman1989]

If after 24 hours the refer is NOT below 38 degrees and the freezer is NOT below 10 degrees, your cooling unit is BAD.

We were actually freezing ice in our freezer to put in a cooler for our food while dry camping on LP. Could the unit be bad and still freeze water?

[mtnman1989]

Thanks Doug!

You should have HI -MED-- LO settings on the gas knob.
Thats correct and I saw the flame go from LO to Med and Hi as wife turned the knob through each setting.

I actually put a small cordless fan inside the lower vent while we were dry camping last week and it didn't help.

With The upper vent off I see an angled piece of wood to divert air toward the cooling unit, I will have to remove it to look for a fan.

We are back home now and hooked up to 110 AC power so I can try more things. By the way, my IR THERMOMETER seems to work on the back side of the freezer showing minus .01 degrees. It registered -8 dry on LP while camping.

[dougrainer]

1. The Thermister is NOT a Thermister. It is a silver capillary tube that runs from the 120 Tstat to the fins on the evaporator.
2. Your Gas tstat selector IS the tstat for the Gas side. You should have HI -MED-- LO settings on the gas knob. Unlike older BYPASS gas tstats, this system does NOT alter the flame height when temp is reached. HI is the coldest setting.
3. Your model SHOULD have a 12 volt cooling fan on the backside between the outer wall and the back of the cooling unit. You may not see it, you may have to remove the upper outside vent/door to see it. IT MUST BE RUNNING FOR COOLING TO HAPPEN. Some models do not have this fan(roof top venting), but for your type of install they are required, especially if NO roof top vent and the cooling air has to come in the bottom vent and then come out the top side vent.
4. WHILE YOUR MODEL IS not 3 WAY (dc BEING THE 3RD heat supply) you should have a 12 volt and neg wire connected to supply power to the cooling fan.
5. Your Tstat sensor tube connects to the 120 Thermostat and then goes to the evap fins. You have 2 separate tstats on your refer. A GAS tstat and a 120 Tstat.
6. The BEST way to test is to connect the 120 element direct to an 120 extension cord for 24 hours. Level the RV and this bypasses all controls. If after 24 hours the refer is NOT below 38 degrees and the freezer is NOT below 10 degrees, your cooling unit is BAD.
32 to 38 is the refer temps and 0 to 10 is the freezer temps. Use a cup of water after 24 hours to measure the refer temp.
DO NOT USE A IR THERMOMETER. They do NOT work for refer temps. Doug