Disabling under voltage protection on Danfoss BD35F

[owen-cox]

Steve
I'm having the exact same problem.
But I have taken apart my thermostat (Waeco CR50 fridge) as you suggest but I don't understand the part about disconnecting the yellow cable because when I do this the fridge doesn't work!

Surely I need this yellow wire to connect somewhere to complete the circuit?

Please could you clarify what I should do. Thanks.

What I believe he means is that Waeco install a resistor with a two spade connectors on a male and female with yellow shrink wrap around it. this goes in line with the thermostat. this lifts the cut out voltage. you simply un plug it at both ends and replace the wire that it came of to the free terminal you unplugged the resistor from. thsi will give you the standard voltage cut out.

 

[GHA]

What I believe he means is that Waeco install a resistor with a two spade connectors on a male and female with yellow shrink wrap around it. this goes in line with the thermostat. this lifts the cut out voltage.

Not so I'm afraid, putting a resistor in line with the thermostat between c & t changes the speed of the compressor, not the cut off voltage. As stated further up it's changed by a resistor between c & p.

 

[vas]

Not so I'm afraid, putting a resistor in line with the thermostat between c & t changes the speed of the compressor, not the cut off voltage. As stated further up it's changed by a resistor between c & p.

Apologies for reviving yet again a thread but there are a couple of things still not clear.

diagram is slightly clearer on a page first linked back at the start of the thread on 2013
http://www.penguinfrigo.co.uk/assets/assets/BD35 Info with 101N0210.pdf

So, first of all a "short" intro:
I have 2 fridges onboard both with BD35F compressors.
A Waeco RPD110 with the 101N0220 and
a Frigo-something 80lt with the 101N0210

I've had problems with the Waeco throughout the season, running very little, stopping soon after I'd stop motoring, not a single day did it manage to run for the whole night, food (or rather drinks after I threw away the first lot...) was lukewarm in the morning. OK ambient was circa 40C...

The Frigo thing was fine.

A lot of headscratching didn't help, but a couple of weeks ago I found by accident that I stupidly had connected the Frigo to 12V through the 24->12 dropper. Explains that throughout the season I had an annoying message on all N2K gauges saying low voltage every 10-15mins. Dropper is a little thing that says 20A and obviously cycling on the fridge was sucking all juice from the poor thing dropping everything else to 9V...

So today rerooted a thick gauge cable from an unused breaker the whole 2.5m to the fridge, brand new spades, connected, tried nada.
Tried the Waeco (on another breaker) light inside on (notice just connects to the power) compressor wont work.
Batteries reasonably charged analogue V on the panel showed 25V or so, digital voltometer showed 24.6 or something like that.

Just for the hell of it, I replugged the Frigo to 12V and surely it fired up!
Run the genny, Waeco started up as well. Took the genny 15mins for the Victron to drop 220V demand to 1A (from 8A) so not fully charged, but charged.

Nice!

Now, my batteries 4X180Ah wet cell service designated (extra Ca on them...) are reasonably new (one 14m) and next month I'll install 500W of solar panels on a f/b hardtop so should really be fine charge wise.
However, I'd expect to be able to run my fridge with 24.6V or so, is it too low, doubt it!

Going to the actual controllers on the BD35Fs and time for questions:

NONE has a wire to the P terminal.
The Frigo one has a 265Ω (says my 20euro digital meter) resistance on the T terminal. Yes I know diagram shows that on C but I doubt it makes any difference... This means the motor will only do 2500rpm. Being in high ambient temps, is that OK, or should I go up in revs (1.5KΩ maxes out the compressor). Will getting the compressor up to 3500rpm reduce its life expectancy or not?
The Waeco has an embedded socket that may incorporate a resistor, I'll check tomorrow.

It's tempting to get a 10KΩ between C and P and see what's going to happen.
Before I do, anyone tried a plain wire or any resistance there?

Also on my Frigo the thermostat is not an easy thing to open up, so I wont go hunting the yellow wire. Anyone had success with that other than the person that recommended it back in 2013?

Enough questions for now!

cheers

V.

 

[nigelmercier]

The position of R8 makes no difference.

Once you realise the terminals are Common, Temperature and Protection they make more sense.

 

[vas]

Once you realise the terminals are Common, Temperature and Protection they make more sense.

v.smart! wouldn't have thought of that.
Will try a plain cable on the Frigo tomorrow and will report back, have it running on 12V so batteries will be a bit lower by the morning and will be a good test.

cheers

V.

PS. don't try editing from a mobile as it tends to delete rather than edit a message...

 

[vas]

an update:

Built a 26KΩ patch and a 0Ω patch.

Tried the Waeco first
The 26ΚΩ in theory should stop the fridge close to 23.8V and start again at 25.2V, Probably worked, but since I was at 25.1 when I closed the breaker it wouldn't start and by firing up the genny it started but it would take hours and hours to drop down to 23.8 to check if it actually stops then.
So tried the 0Ω and indeed it started fine and worked fine (still have it there running to check later) with around 25V on the contacts.

Then went to the Vertifrigo
To start with, it wont work no matter what with the 24V, 12V is fine, but not 24V
Tried both patches, nada.
So seems like I have a problem to solve there. Undid the controller by the side of the compressor (that's where all the spades terminals are) and there's no jumper or anything that I could tune there. Just the board rather tired and very very dark brown, possibly from heat and the years, dunno...
Will probably built a led testbed to check the errorcodes.

Any ideas on why the Vertifrigo wont start at 24V (not even 27.something when the genny fires up!) but is happy on 12 (13.3V actually as it's from the dropper which does keep a constant current going)???

cheers

V.

 

[nigelmercier]

Are you sure both units can run on 24V?

 

[vas]

Are you sure both units can run on 24V?

yep both danfoss BD35F say 12/24V on the side controller thing where the spade terminals are, so I assume both are 24V compatible

V.