Norcold 740 or 751 any good?
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SternWake
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Interesting that they have relocated the condenser to the very bottom of the fridge.
On page 7 here on the 740
http://www.thetford.com/wp-content/uploads/2015/04/NR740-NR751-Installation-Owners-Manual.pdf
The Danfoss compressor and controller also require some airflow too. Not sure how they accomplpish this.
I had an older Sawafuji de0040 Norcold. Its door seals were better than my current Vitrifrigo c51is but the VF is the hands down winner in all other regards in my opinion.
I'd compare Norcold's prices to them.
http://www.vfamerica.com/eng/classic-series.html
I bought my VF from this guy in 2012:
http://www.westyventures.com/parts.html#cart_restore
On page 7 here on the 740
http://www.thetford.com/wp-content/uploads/2015/04/NR740-NR751-Installation-Owners-Manual.pdf
The Danfoss compressor and controller also require some airflow too. Not sure how they accomplpish this.
I had an older Sawafuji de0040 Norcold. Its door seals were better than my current Vitrifrigo c51is but the VF is the hands down winner in all other regards in my opinion.
I'd compare Norcold's prices to them.
http://www.vfamerica.com/eng/classic-series.html
I bought my VF from this guy in 2012:
http://www.westyventures.com/parts.html#cart_restore
mdhg
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I read through the bottom grill it draws air in one side and exhausts out of the other. (page 8) first paragraph
Does the vitrifridgo need to be vented to the outside or outside the cabinet? how do you have your's vented?
thanks for the recommendation
Does the vitrifridgo need to be vented to the outside or outside the cabinet? how do you have your's vented?
thanks for the recommendation
SternWake
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My cooling unit is located on the top back of the 1.8 cubic foot fridge, A 120MM fan is attached to condenser of the same size, and this then blows across compressor then compressor controller.
I allowed my fan to pull filtered air from behind and below my fridge, and then it exhauset either out a louvered vent outside my conversion van sliding window behind fridge, or into the adjacent portion of the cabinet where my other electrics reside and where another exhaust fan also resides. I vent to interior in winter and exterior in summer.
Technically they only need so much passive venting to operate properly, but the better the airflow across the condenser, the shorter amount of time the compressor will need to run.
I have no idea how well the Norcol'd condenser vents its heat, but it does vent it to the floor, right next to where it pulls in the air.
My filter taps a lot of dust and lint. i fear such a condenser location as Norcold's design, would quickly get occluded and hinder performance, but is a good option for those who cannot vent the condenser in the cabinet any other way.
Back in the 90;s, Norcold developed the Nevercold moniker, as their design allowed installers to just slam them home in a cabinet without adequate ventilation to vent heat removed from box to atmosphere. My old Norcold has a passive condenser, but a certain amount of Airflow was designed into the feet and front panel so an uncaring or ignorant installer couldn't screw it up too badly.
I;d say the ability for the condenser vent heat to atmosphere is the single biggest factor in how much electricity a fridge consumes, next is the insulation and door seals.
The Norcold might be idiot proof, but a Non idiot might be able to get more efficiency by proper venting of Condenser through the design of the cabinet into which it is mounted. And if the cabinet has not yet been designed, then design it with an extra 3/4 inch of foamboard insulation, or more, all around the 5 sides of the fridge.
The Danfoss controller allows for one to power 0.5 amps of fans that come on with the compressor. the fan which came with mine consumed 0.12 amps, I replaced it with a quieter one that consumes 0.05 amps and actually performs better pushing Air into condenser, rather than pulling it as original fan did.
One can easily add another exhaust, or intake fanm to further assist airflow across condenser compressor and compressor controller for much better overall performance.
Two Noctua NF-f12 fans consume less electricity than the fan provided with my fridge did and work much better. but I only require one fan in my design, but the secondary fan is easy to add.
recent thread on this topic:
https://vanlivingforum.com/Thread-Fan-on-fridge-compressor-If-so-where
I allowed my fan to pull filtered air from behind and below my fridge, and then it exhauset either out a louvered vent outside my conversion van sliding window behind fridge, or into the adjacent portion of the cabinet where my other electrics reside and where another exhaust fan also resides. I vent to interior in winter and exterior in summer.
Technically they only need so much passive venting to operate properly, but the better the airflow across the condenser, the shorter amount of time the compressor will need to run.
I have no idea how well the Norcol'd condenser vents its heat, but it does vent it to the floor, right next to where it pulls in the air.
My filter taps a lot of dust and lint. i fear such a condenser location as Norcold's design, would quickly get occluded and hinder performance, but is a good option for those who cannot vent the condenser in the cabinet any other way.
Back in the 90;s, Norcold developed the Nevercold moniker, as their design allowed installers to just slam them home in a cabinet without adequate ventilation to vent heat removed from box to atmosphere. My old Norcold has a passive condenser, but a certain amount of Airflow was designed into the feet and front panel so an uncaring or ignorant installer couldn't screw it up too badly.
I;d say the ability for the condenser vent heat to atmosphere is the single biggest factor in how much electricity a fridge consumes, next is the insulation and door seals.
The Norcold might be idiot proof, but a Non idiot might be able to get more efficiency by proper venting of Condenser through the design of the cabinet into which it is mounted. And if the cabinet has not yet been designed, then design it with an extra 3/4 inch of foamboard insulation, or more, all around the 5 sides of the fridge.
The Danfoss controller allows for one to power 0.5 amps of fans that come on with the compressor. the fan which came with mine consumed 0.12 amps, I replaced it with a quieter one that consumes 0.05 amps and actually performs better pushing Air into condenser, rather than pulling it as original fan did.
One can easily add another exhaust, or intake fanm to further assist airflow across condenser compressor and compressor controller for much better overall performance.
Two Noctua NF-f12 fans consume less electricity than the fan provided with my fridge did and work much better. but I only require one fan in my design, but the secondary fan is easy to add.
recent thread on this topic:
https://vanlivingforum.com/Thread-Fan-on-fridge-compressor-If-so-where
mdhg
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wow stern wake your system looks very efficient, nice design! I learned a lot from your posts, thanks The norcold design looks inferior to the VF design and VF is less expensive. no contest there.
The truck fridge 49 is looking pretty good on a tight budget. Is there that large of a quality differnence between that and the VF? Is the TF49 a good fridge?
-matt
The truck fridge 49 is looking pretty good on a tight budget. Is there that large of a quality differnence between that and the VF? Is the TF49 a good fridge?
-matt
mdhg
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I emailed norcold for more info on the fridges:
TO: Norcold
Can you tell me how many amps the nr740bb and nr751bb each draw when operating? Do you have the average time the compressor is on at 80 degrees F or similar information?
Thanks,
Matt
REPLY:
Good afternoon Matt,
On AC these units draw 0.75 Amps at 70 degrees ambient temperature. On DC these units draw 3.6 Amps at 70 degrees ambient temperature. Unfortunately we do not have an average on the time the compressor runs.
If you have additional questions, please contact us.
TO: Norcold
Can you tell me how many amps the nr740bb and nr751bb each draw when operating? Do you have the average time the compressor is on at 80 degrees F or similar information?
Thanks,
Matt
REPLY:
Good afternoon Matt,
On AC these units draw 0.75 Amps at 70 degrees ambient temperature. On DC these units draw 3.6 Amps at 70 degrees ambient temperature. Unfortunately we do not have an average on the time the compressor runs.
If you have additional questions, please contact us.
SternWake
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All the fridges will be very similar in total energy consumed, in an open air space, not residing in a cabinet. The main difference is in the insulation and door seal. You will not find any meaningful information as to which fridge is more efficient
The design of the cabinet itself and how if affects the condensers ability to remove heat is a very large factor.
The latest norcold's floor mounted condenser is interesting, but is kind of like putting a lit match under an ice cube. with a little insulation in between in my opinion, but it does reduce the chance for installer error.
The Danfoss compressor rpm is controllable with a resistor inline on tstat circuit. the danfoss compressor amp draw actually decreases in the 5 minutes it runs.
Mine at 2000 rpm starts at 2.8 amps and is about 2.2 amps 5 minutes later
a 3.6 amp draw would likely be around 2750rpm is my estimation
it is said the slowest rpm which can maintain less than a 50% duty cycle is most efficient.
When my VF was running a 270 ohm resistor for 2500 rpm, compressor run times were abour 45 seconds less, but well below 50%, actually below 25%, so I removed it for 2000 rpm and slightly longer compressor run times.
Now there is so little current flowing through this t stat circuit, one could use a potentiometer and actually crank it up if loading the fridge with warm beer for that nights party, and back down once it is cold. Some of the The chest style frdges appear to control Danfoss compressor speed in this way, automatically.
While I have an affinity for manual control of fan speed or LED light intensity or charge voltage via potentiometers, I have not bothered with this modification for my fridge.
As far as the TF49 goes. Its plumbing is different, as is the Condenser and Fan. The VF has the compressor and condenser mounted on the same plate isolated on rubber feet from the fridge box, and uses a 120MM fan on the condenser. The TF49 has the condenser screwed to the fridge box directly, separately than the condenser. This means the copper lines have to flex a bit more with compressor vibration. Also the fan used by the TF appeared, at least 5 years ago, to be a 92MM fan which only covered a smaller portion of the condenser, and is reported to be a higher speed fan, meaning louder.
My VF, I relocated the fan to the other side of condenser to push Air, but the TF has some copper plumbing in the way which would have prevented this fan relocation.
While I do now have a filter on my air intake, this was not always the case, and if I could not have relocated the fan, then leaving it in place would make cleaning the fan blades extremely difficult. Even with the filter, the fan blades and condenser fins do accumulate a much finer dust on the leading edges. I suspect many compressor fridge demises are not just the Ciggy plugs failing, but also due to accuulation of dust on fan and condenser which will increase compressor run times and wear on the compressor, and Battery powering it.
So When designing the cabinet for the fridge, do not make it so difficult to remove and access the condenser for a little maintenance. Mine is just one anderson powerpole electrical connector, and 4 screws and I can slide it out, but my third chair makes it a tight fit and it is easier to remove the 4 nuts holding the chair portion in place first.
I Should do so today. It has been a long while since I last cleaned the fridge fan.
This photo was taken pre filter:
The design of the cabinet itself and how if affects the condensers ability to remove heat is a very large factor.
The latest norcold's floor mounted condenser is interesting, but is kind of like putting a lit match under an ice cube. with a little insulation in between in my opinion, but it does reduce the chance for installer error.
The Danfoss compressor rpm is controllable with a resistor inline on tstat circuit. the danfoss compressor amp draw actually decreases in the 5 minutes it runs.
Mine at 2000 rpm starts at 2.8 amps and is about 2.2 amps 5 minutes later
a 3.6 amp draw would likely be around 2750rpm is my estimation
it is said the slowest rpm which can maintain less than a 50% duty cycle is most efficient.
When my VF was running a 270 ohm resistor for 2500 rpm, compressor run times were abour 45 seconds less, but well below 50%, actually below 25%, so I removed it for 2000 rpm and slightly longer compressor run times.
Now there is so little current flowing through this t stat circuit, one could use a potentiometer and actually crank it up if loading the fridge with warm beer for that nights party, and back down once it is cold. Some of the The chest style frdges appear to control Danfoss compressor speed in this way, automatically.
While I have an affinity for manual control of fan speed or LED light intensity or charge voltage via potentiometers, I have not bothered with this modification for my fridge.
As far as the TF49 goes. Its plumbing is different, as is the Condenser and Fan. The VF has the compressor and condenser mounted on the same plate isolated on rubber feet from the fridge box, and uses a 120MM fan on the condenser. The TF49 has the condenser screwed to the fridge box directly, separately than the condenser. This means the copper lines have to flex a bit more with compressor vibration. Also the fan used by the TF appeared, at least 5 years ago, to be a 92MM fan which only covered a smaller portion of the condenser, and is reported to be a higher speed fan, meaning louder.
My VF, I relocated the fan to the other side of condenser to push Air, but the TF has some copper plumbing in the way which would have prevented this fan relocation.
While I do now have a filter on my air intake, this was not always the case, and if I could not have relocated the fan, then leaving it in place would make cleaning the fan blades extremely difficult. Even with the filter, the fan blades and condenser fins do accumulate a much finer dust on the leading edges. I suspect many compressor fridge demises are not just the Ciggy plugs failing, but also due to accuulation of dust on fan and condenser which will increase compressor run times and wear on the compressor, and Battery powering it.
So When designing the cabinet for the fridge, do not make it so difficult to remove and access the condenser for a little maintenance. Mine is just one anderson powerpole electrical connector, and 4 screws and I can slide it out, but my third chair makes it a tight fit and it is easier to remove the 4 nuts holding the chair portion in place first.
I Should do so today. It has been a long while since I last cleaned the fridge fan.
This photo was taken pre filter:
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