danfoss fridge, internal fan operation?

[Cactus Sailing]

having a little issues with my fridge on my boat, it cools down inside but there is no air flow as the internal fan does not operate, but I cant work out how its meant to be wired as its not on the below diagram and appears to be connected via the thermostat inside the fridge?

once the plate inside is cold the fridge switches off, but with the internal fan not running, it doesn't exactly keep the beer cold, and I think because the area around the thermostat is cold the fridge cuts out

connected to + & F is the fan on the compressor side of the fridge the 120cmx25 box fan, not the inside fridge one, but where / how should the internal fan be connected, its not currently getting 12v, so when should it run? same time as the external fan?

any help appreciated.

 

[rogerthebodger]

My Danfoss based fridge is keel cooled so no external fan. I fitted an computer fan inside my fridge and connected to the + and 5 terminal in the same way as the external fan is connected.

 

[Graham_Wright]

I fitted a computer inside my fridge and connected to the + and 5 terminal in the same way as the external fan is connected.

 

[rogerthebodger]

Typing to slow and missed the fan.

 

[Graham_Wright]

Typing to slow and missed the fan.

It's when it hits the fan you generally have problems!

 

[pcatterall]

having a little issues with my fridge on my boat, it cools down inside but there is no air flow as the internal fan does not operate, but I cant work out how its meant to be wired as its not on the below diagram and appears to be connected via the thermostat inside the fridge?

once the plate inside is cold the fridge switches off, but with the internal fan not running, it doesn't exactly keep the beer cold, and I think because the area around the thermostat is cold the fridge cuts out

connected to + & F is the fan on the compressor side of the fridge the 120cmx25 box fan, not the inside fridge one, but where / how should the internal fan be connected, its not currently getting 12v, so when should it run? same time as the external fan?

any help appreciated.

That diagram looks like the typical one for the danfos compressor operation. The motor fan may well 'run on' after the compressor cuts out but I guess your internal fan needs to run whenever the fridge is on. If you cant trace where the 12v power should really come from then Is a bodge job not feasible? like power direct from unit on off switch? I assume that the internal fan will be 12v?

 

[vyv_cox]

My fridge is once-through seawater cooled, built as a special. The pump is wired as if it was the fan in your diagram, so it switches on and off with the thermostat. I don't think there would be any point in having it (or a fan) running at any other time. The fans I have seen on Frigoboat versions of the Danfoss compressor are immediately adjacent to the condenser, not inside the fridge itself.

 

[rogerthebodger]

In the OP's diagram the two + symbles are 12 volte anf the fan is switched by the negative through the F connection.

I also have an indicator LED to show ne when the fridge motor is running and if the fan runs on a little after the motor has stopped not a problem in my view.

 

[Graham_Wright]

Perhaps a separate fan thermostat is the answer? Placed at the top of the cavity, it would stir the air when needed.

 

[Cactus Sailing]

That diagram looks like the typical one for the danfos compressor operation. The motor fan may well 'run on' after the compressor cuts out but I guess your internal fan needs to run whenever the fridge is on. If you cant trace where the 12v power should really come from then Is a bodge job not feasible? like power direct from unit on off switch? I assume that the internal fan will be 12v?

Yeah that's why I wanted to know when the internal fan should operate! I don't think the fan should be on 24/7 as with all other boats iv been on it's intermittent running.

I would assume wiring it into the external fan would be fine (yes they're both 12v) but wanted someone ideally to confirm when their internal fan runs

 

[Cactus Sailing]

That diagram looks like the typical one for the danfos compressor operation. The motor fan may well 'run on' after the compressor cuts out but I guess your internal fan needs to run whenever the fridge is on. If you cant trace where the 12v power should really come from then Is a bodge job not feasible? like power direct from unit on off switch? I assume that the internal fan will be 12v?

Yeah that's why I wanted to know when the internal fan should operate! I don't think the fan should be on 24/7 as with all other boats iv been on it's intermittent running.

I would assume wiring it into the external fan would be fine (yes they're both 12v) but wanted someone ideally to confirm when their internal fan runs

 

[GHA]

Perhaps a separate fan thermostat is the answer? Placed at the top of the cavity, it would stir the air when needed.

Somes complicated, why not just wire a little computer fan in parallel with the compressor fan across "F" & "+" ?


Should anyone be interested this is what the temps of the cold plate & a sensor at the bottom of the fridge look like, no internal fan.

 

[Graham_Wright]

Somes complicated, why not just wire a little computer fan in parallel with the compressor fan across "F" & "+" ?


Should anyone be interested this is what the temps of the cold plate & a sensor at the bottom of the fridge look like, no internal fan.

That's fascinating. A thermostat is a simple thing and, wired in series with the fan would smooth out those peaks and troughs.

 

[rogerthebodger]

Should anyone be interested this is what the temps of the cold plate & a sensor at the bottom of the fridge look like, no internal fan.

Its the temperature at the top of the fridge that is the real problem as cold air sinks.

The reason I fitted an internal circulation fan was that the temperature at the top of the fridge did not get low enough when while the items at the bottom of the fridge became frozen.

 

[Cactus Sailing]

That's fascinating. A thermostat is a simple thing and, wired in series with the fan would smooth out those peaks and troughs.

And this is how I think it's supposed to be wired in series with the thermostat, perhaps the stat switch is broke? Would the plate still get cold if the stat was broke though??? Could be onto something here

 

[Graham_Wright]

And this is how I think it's supposed to be wired in series with the thermostat, perhaps the stat switch is broke? Would the plate still get cold if the stat was broke though??? Could be onto something here

You would need the " fan stirrer" thermostat to be set to a higher temperature than that for the compressor.

 

[Cactus Sailing]

You would need the " fan stirrer" thermostat to be set to a higher temperature than that for the compressor.

what?

there is one thermostat for the fridge...

if anyone can just tell me when the internal fan needs to be on ill figure it out

 

[vyv_cox]

I have to say I have never seen an internal evaporator fan on a small fridge such as found on a boat. Modern large frost-free fridges have them but otherwise new to me. With the evaporator at the top, as most boat front opening fridges have, I don't understand why one would be needed.

 

[Graham_Wright]

what?

there is one thermostat for the fridge...

if anyone can just tell me when the internal fan needs to be on ill figure it out

If you decide to fit a fan to keep all the fridge at the same temperature, you need to fit the (a) thermostat at the top where the warmer air will rise. As Viv says, if the evaporator is at the top and the compressor thermostat is at the top, the temperature should stay reasonably the same throughout the whole interior and you don't need to "stir".

 

[Cactus Sailing]

I have to say I have never seen an internal evaporator fan on a small fridge such as found on a boat. Modern large frost-free fridges have them but otherwise new to me. With the evaporator at the top, as most boat front opening fridges have, I don't understand why one would be needed.

here is the internal part, with fan... the plate is behind the plastic cover air should be drawn in from the top and blown across the cold plate and out the bottom.

If you decide to fit a fan to keep all the fridge at the same temperature, you need to fit the (a) thermostat at the top where the warmer air will rise. As Viv says, if the evaporator is at the top and the compressor thermostat is at the top, the temperature should stay reasonably the same throughout the whole interior and you don't need to "stir".

it already has a fan attached, I just want to know how it is supposed to work so I can fix it applying 12v and it works... so could be;

a) wired wrong (its was covered in tape)
b) thermostat switch broke

unfortunately all wiring diagrams omit the internal fan...