Community Forums

Mudfrog · 04-06-2021, 12:29 PM

Our older rig has a Norcold mounted in the slide. It's always worked well but I figured it wouldn't hurt to add an auxiliary fan to help circulate air across the condenser tubing. I know most people install the fan(s) above but I decided to just install inside the lower hatch and let it push air upwards. It's a very low volume pc case type fan.

My question. The oem built in fan is thermostatically controlled. I wired the new fan to run anytime the refrigerator is turned on. Besides the obvious wear tear on the little fan, is there any problem letting it run continuously?

TXiceman · 04-06-2021, 12:32 PM

In cold weather, you should turn off the extra fan.

Ken

ttavasc · 04-06-2021, 12:38 PM

It's easy to add a thermostat switch when you wire the new fan in. This is what I did when I added a fan to the fridge vent on our previous Jayco unit. You can find them on Amazon for ~$15.

Old-Biscuit · 04-06-2021, 12:49 PM

Reason OEM is mounted above the absorber tube bundle and thermostat controlled is fans pull air in 'thru' the tube bundle and then directly push the air flow up thru the condenser fins
Thermostat senses condenser FIN temps....turn on when FIN temp reaches 130*F and back off when FIN temp drops to 115*F
*Temps above 130*F and less condensing of hot ammonia vapor
*Temps below 115*F and natural air flow is sufficient for condensing the hot ammonia vapor

When ambient air temps drop below 50*F enhanced airflow is not needed.........at that temp a 'heat load' can help (LAT/Low Ambient Temp System IE: some fridges have a switch that turns on the interior light to cause heat load so duration of cooling cycles is extended)

Although not the best location for additional fans you should install a on/off switch OR another thermostat on condenser fin
Either case....should have an in-line fuse (1A) close to where you tied into the DC Power

Thermostat -----Norcold 618093 (works on ANY Brand fridge)
$14 on-line

Mudfrog · 04-06-2021, 01:53 PM

For now, I inserted the small fan wires into the existing spade connections that lead to the oem fan. They're only hot when the frig is switched on. I realized I would need to de-energize the fan in cooler temps so have it to where it's easy to do just that. My initial thinking was that it would be ok to just let it run when outside air temperatures were above, say 75°.

Controlling the fan with a thermostat or snap disc is something I originally thought about. To maybe help with wear and tear on the oem fan, I thought it might be good if it closed before the oem fan snap disc closed. I wasn't exactly sure how to accomplish that.

Again, the frig works fine as is. My thinking is the little extra air flow might just help the old 19 year old go another 19 years.

litzdog911 · 04-07-2021, 10:47 AM

We added an ARP Fridge Defend to our Norcold, along with stack fans and interior refrigerator fans. Check out the resources at their web site.

Mudfrog · 04-24-2021, 12:20 PM

Thought I'd throw in an update. Note, there are variables and this was not a real accurate test.

Had initially installed the fan without any kind of thermostat. Left it unpowered until temps got hot enough for the oem fan to come on. Outside temp was around to 80°F with the sun hitting the side. Powered up the fan, checked an hour or two later, and found that the oem fan had stopped running. Outside temp about the same. Next day, wired up the fan to run before the oem fan came on. Air temp about the same as the day before. Monitored off and on, oem fan never came on.

Went 7 more days, powering on only when temps got to above 70°, and never heard the oem fan come on.

Got home and ended up ordering a cheapy thermostat. Installed but i have not had a chance to see how well it works. The the stat's specs show a wide differential (hysteresis) of around 7°C which may make it difficult to make work with my application. Will trial and error it with different settings the next time we go out. My attempt is to use it to measure air temp inside the cavity, not the refrigerant tubing temperature. May have to try something else if that doesn't work sufficiently.

Here's an image of my installation. Fan is mounted at the top, thermostat is the little box at the bottom left. Wired into existing oem fan wiring.

Edited to add: Didn't have a thermometer but did note that the ice cream was not as soft as usual.

jacknife · 04-24-2021, 02:30 PM

Quote:

Originally Posted by Mudfrog

Thought I'd throw in an update. Note, there are variables and this was not a real accurate test.

Had initially installed the fan without any kind of thermostat. Left it unpowered until temps got hot enough for the oem fan to come on. Outside temp was around to 80°F with the sun hitting the side. Powered up the fan, checked an hour or two later, and found that the oem fan had stopped running. Outside temp about the same. Next day, wired up the fan to run before the oem fan came on. Air temp about the same as the day before. Monitored off and on, oem fan never came on.

Went 7 more days, powering on only when temps got to above 70°, and never heard the oem fan come on.

Got home and ended up ordering a cheapy thermostat. Installed but i have not had a chance to see how well it works. The the stat's specs show a wide differential (hysteresis) of around 7°C which may make it difficult to make work with my application. Will trial and error it with different settings the next time we go out. My attempt is to use it to measure air temp inside the cavity, not the refrigerant tubing temperature. May have to try something else if that doesn't work sufficiently.

Here's an image of my installation. Fan is mounted at the top, thermostat is the little box at the bottom left. Wired into existing oem fan wiring.

Edited to add: Didn't have a thermometer but did note that the ice cream was not as soft as usual.

If you cannot adjust the temp and it is a Dometic . Go on line and look up thermistor for Dometic . There is a thermostat for sale about 25 real easy to install in fridge . It has a small dial it will freeze your fridge . Been using it for theee years no problem .

Mudfrog · 04-24-2021, 04:07 PM

Quote:

Originally Posted by jacknife

If you cannot adjust the temp and it is a Dometic . Go on line and look up thermistor for Dometic . There is a thermostat for sale about 25 real easy to install in fridge . It has a small dial it will freeze your fridge . Been using it for theee years no problem .

Have no trouble adjusting the cooling temp inside the frig, that's always worked well. My attempt here was to maybe make the cooling/heating exchange process on the condenser side of the frig more efficient on those warmer days. Maybe even save some wear and tear on the oem fan.

Also thinking that the new fan might provide enough air flow to keep things running if the oem ever died.

tankcj · 04-27-2021, 01:51 PM

Quote:

Originally Posted by Mudfrog

Have no trouble adjusting the cooling temp inside the frig, that's always worked well. My attempt here was to maybe make the cooling/heating exchange process on the condenser side of the frig more efficient on those warmer days. Maybe even save some wear and tear on the oem fan.

Also thinking that the new fan might provide enough air flow to keep things running if the oem ever died.

I added fans for the same reason and also determined that while I had OEM fans, the thermostat wasn't working. Thanks to Old-Biscuit, I ended up with this...

https://www.irv2.com/forums/f54/dome...ns-443726.html

cletesingler · 04-27-2021, 06:50 PM

Being in TX in the summer, with normal temps 100 degF and more, I also added a fan in the upper area and control it manually - and it does help, but not enough. So I added 2 JRRefrigeration clip-on fans to the inside fins, and that was the answer. My big problem now is during non-summer days the fridge is freezing with inside fans ON! But in summer, I'm lucky to keep the fridge at or below 40 degF. Once you open one of the doors, there goes the temp.....

Mudfrog · 04-27-2021, 08:07 PM

Quote:

Originally Posted by tankcj

I added fans for the same reason and also determined that while I had OEM fans, the thermostat wasn't working. Thanks to Old-Biscuit, I ended up with this...

https://www.irv2.com/forums/f54/dome...ns-443726.html

I like the looks of your installation, and yes, Old Biscuit knows his stuff!

For mine, I knew beforehand that the fan would probably be more efficient pulling air across the coil. But since this was just meant to aid air flow in the hotter months, I went ahead and installed to push air upwards,, (easier to do with power available close by).

You stated that you were letting ambient air temperature control the fans. Has this worked out well, and if so, what kind of thermostat are you using? Asking because I'm not all that confident the one I installed is going to control the fan the way I want it to.

Thanks!

tankcj · 04-27-2021, 08:19 PM

Quote:

Originally Posted by Mudfrog

I like the looks of your installation, and yes, Old Biscuit knows his stuff!

For mine, I knew beforehand that the fan would probably be more efficient pulling air across the coil. But since this was just meant to aid air flow in the hotter months, I went ahead and installed to push air upwards,, (easier to do with power available close by).

You stated that you were letting ambient air temperature control the fans. Has this worked out well, and if so, what kind of thermostat are you using? Asking because I'm not all that confident the one I installed is going to control the fan the way I want it to.

Thanks!

85 deg thermostat from RV Cooling Unit Warehouse. It’s mounted near the coil but not on it like the OEM. The original fans are mounted about midway on the back of the fridge pushing air up over the coils. The fans I installed are pulling air up over the coils and out the top side vent.