Fridge replacement

Discussions regarding electronics, gear and other equipment of maintenance issues that ARE NOT SPECIFIC to a certain PDQ model yacht
User avatar
holomoku
skipper
skipper
Posts: 61
Joined: Mon Jan 18, 2010 7:37 pm
Location: PDQ 36 Grizabella

Fridge replacement

Postby holomoku » Wed Aug 18, 2010 7:34 pm

Fridge is dead on 1993 PDQ 36.
I tried recharging the system and that worked for a day or so but the compressor wont start now.
It tries, but then overloads and shuts down...
I have a Nova Kool and they sell a nice replacement unit but the price is giving me sticker shock.
right around $1000 for a compressor, cooling plate and thermostat.

Anyone have a lead on good prices for fridge replacement using the existing cooling box?

User avatar
Lady of the Lake
Site Admin
Posts: 614
Joined: Wed Dec 22, 2004 2:37 pm
Location: Punta Gorda, FL (36015)
Contact:

Re: Fridge replacement

Postby Lady of the Lake » Wed Aug 18, 2010 8:32 pm

Always liked www.rparts.com for parts and components and www.defender.com for systems.

Sam
Sam and Gina Densler
s/v Lady of the Lake
PDQ36 Hull #15
Punta Gorda, FL

User avatar
MagicDragon
skipper
skipper
Posts: 84
Joined: Mon May 19, 2008 4:37 pm
Location: east of Cleveland Ohio
Contact:

Re: Fridge replacement

Postby MagicDragon » Thu Aug 19, 2010 7:40 am

Look on EBay under RV fridge and you'll find some bargains, but make sure seller has high feedback rating (at least 99%). Also http://greatlakesskipper.com has some, though not any Nova Kool at the moment. Good luck!
http://www.MagicDragonPDQ.com
Angela Barbati
S/V Magic Dragon 36054
near Cleveland, OH

carib sailor
1st mate
1st mate
Posts: 48
Joined: Wed Jan 02, 2008 1:26 pm

Re: Fridge replacement

Postby carib sailor » Thu Aug 19, 2010 12:16 pm

Having repaired my reefer a few times....if the Nova Kool uses a 12vdc Danfoss compressor, it's probably not dead. They are very durable units.

There are quite a few things that will stop the compressor from starting, almost all are easily corrected.

User avatar
holomoku
skipper
skipper
Posts: 61
Joined: Mon Jan 18, 2010 7:37 pm
Location: PDQ 36 Grizabella

Re: Fridge replacement

Postby holomoku » Thu Aug 19, 2010 12:34 pm

carib sailor wrote:Having repaired my reefer a few times....if the Nova Kool uses a 12vdc Danfoss compressor, it's probably not dead. They are very durable units.

There are quite a few things that will stop the compressor from starting, almost all are easily corrected.


That's encouraging.....

When I flip on the breaker the compressor makes a single squeak, is drawing 5-6 amps as I recall, then after about 15 seconds, something switches off and amps drop to zero.

After about 45 seconds, it tries again with same result.....then repeats.

I checked resistances on the motor per specs I found online and all looked OK.

Any ideas appreciated
Thanks for all the responses so far

carib sailor
1st mate
1st mate
Posts: 48
Joined: Wed Jan 02, 2008 1:26 pm

Re: Fridge replacement

Postby carib sailor » Thu Aug 19, 2010 2:15 pm

Is it a Danfoss? What model is the compressor?

What model is the module?

User avatar
holomoku
skipper
skipper
Posts: 61
Joined: Mon Jan 18, 2010 7:37 pm
Location: PDQ 36 Grizabella

Re: Fridge replacement

Postby holomoku » Thu Aug 19, 2010 9:45 pm

Pretty sure it is a danfoss but I can't put my hands on the photos I took of the model plate.
I will repost when I get down to the boat tomorrow and get specific info.

Thanks,
Spencer

User avatar
maxicrom
admiral
admiral
Posts: 219
Joined: Fri Jun 06, 2008 12:29 pm
Location: II the Max (PDQ36 #12), Washington DC

Re: Fridge replacement

Postby maxicrom » Fri Aug 20, 2010 11:40 am

Spencer,

If you have to replace your unit - you may want to look at an EZ Kold unit, they are usually at the Annapolis boat show. http://www.e-zkold.com/ We are using a unit from our previous boat so it is about 8 or 9 years old now and still working fine (the unit in the boat failed shortly after we bought it).

What we like about the EZ Kold is that there system uses a substantial cold plate so the box will stay cold for a few days without any power. When we ordered ours they built the cold plate to the dimensions of our box at no extra charge - luckily it fit right into the PDQ box - was a little work to mount as the plate is heavy and my shoulders don't fit into the box very well to get to the back. In hindsite I may have mounted it on the side if I were to do it again. Bottom line is that it works pretty well - I added a thru-hull for the water cooling but haven't installed it yet.

hope this helps, hopefully you can get your unit working - the EZ Kold was in the $700 - $1000 price range,

Mike
Mike & Linda
S/V II the Max

User avatar
holomoku
skipper
skipper
Posts: 61
Joined: Mon Jan 18, 2010 7:37 pm
Location: PDQ 36 Grizabella

Re: Fridge replacement

Postby holomoku » Fri Aug 20, 2010 10:00 pm

OK I got down to the boat this evening for a quick look at the fridge compressor.

It is an older Danfoss BD 2.5.

I am having troulble reading the number on the controller. It is faded but I think i can read it with a magnifier....next time.

The unit as a whole is a Nova Kool LT200.

I did some more digging and found that a bad fan or a bad controller can sometimes cause a failure to start.
I'll try disconnecting the fan next time.

Any other suggestions ?

carib sailor
1st mate
1st mate
Posts: 48
Joined: Wed Jan 02, 2008 1:26 pm

12vdc Reefer - Troubleshooting tips

Postby carib sailor » Sat Aug 21, 2010 8:04 am

I'm not a refrigeration expert. My fridge croaked a few times in the middle of nowhere and I just learned a few things about it while fixing it and while helping a couple of other people who were stuck too. When the beer gets warm I get motivated!

FWIW, in my opinion it's well worth the cost to hire a professional locally if you can find one. It's easy to damage a fridge system so proceed with caution and hire a pro if you can. I think it's worth it, especially if you can spend a few bucks and avoid the hassle and cost of replacing the whole thing.

Having said that, here are a few things that I figured out along the way that might be helpful to know.

In my experience, the most common causes of compressor no start issues (meaning the fridge tries to start but the compressor doesn't fire up) with Danfoss compressors, in order of likelihood are:

1) Bad power - Even if your batteries are showing 12.6 volts or more you could still have a power issue. You can't measure the voltage with a meter because even very short fluctuations (mili-seconds) will cause a no start. The two culprits that usually cause a no start are bad connections and "iffy" batteries. This is BY FAR the most common cause of compressor no start issues in my experience (unless someone has attempted to add refrigerant - see 3 below).

I have seen bad connections at the module and/or breaker panel cause a low voltage - no start condition. I have seen defective batteries cause it, and I once saw a defective circuit breaker cause short duration (mili-second) low power issues that lead to no start.

2) Fan drawing too much current - Temporarily disconnect the fan from the module and see if the compressor starts. The fan should be easy to change if it's the culprit. But before you replace it clean it inside. A ton of dust collects in and around the fan and if it starts to "clog" it will cause the fan to draw too much current. The module will pick up on that and shut down to prevent damage. Also, if your fridge runs but is not getting as cold as it should, clean the fins on the condenser and clean the fan too. They should be cleaned regularly. If you have water cooling, make sure that a good water flow is present as fouled thru-hulls and strainers cause the fridge to get warmer than normal. So does damaged door seals and air leaks (obviously).

3) Compressor won't come up to speed - the only times that I personally have seen this is when the fridge has been improperly "topped up" with refrigerant. Adding refrigerant should be a last resort and in my opinion should only be done if the pressure has been measured and the pressure is low. Sometimes when people add refrigerant they accidentally introduce air, moisture, or dirt into the system or the system gets overfilled. Adding refrigerant has to be done properly and of course the correct type of refrigerant must used. Using the wrong refrigerant will do damage.

"Topping up" should not be required unless there is a leak and it should not be done unless the leak has been repaired. The compressor will run continuously if there is a leak and there is no (or low) refrigerant in the system. In my experience, low refrigerant will not cause a no start situation it will just make the fridge warm instead of cold.

4) Defective Module - the only way that I know of to confirm this is to replace the module HOWEVER you should NEVER replace a module without first making sure that the resistance on the compressor pins is correct. There are four pins on the compressor on a BD2.5 and BD3. There are 3 pins on the newer BD35 and BD50 compressors. You can find the correct resistances online. If you have a defective compressor and put in a new module you are likely to blow the new module so it's a good idea to check the compressor resistances first.

Obviously a defective compressor would cause a no start issue, but I have not yet encountered a dead Danfoss compressor (except for one on a boat struck my lightning and everything was dead!). I'm sure it happens, but I personally haven't seen it as yet.

An electronic module controls the compressor. When the thermostat calls for the fridge to come on the module attempts to start the compressor and at that time the module runs a short diagnostic routine. It tries to start the fridge for about 5 seconds or so. If it doesn't start, a piezoelectric buzzer sounds briefly inside the module and then the module waits about 45 seconds or so and tries again. Depending on the model of module that you have, you can connect a diagnostic LED across two pins on the module. When the fridge tries to start and fails, the diagnostic LED flashes. The number of flashes will tell you whether you have a lower power issue, a fan overload issue, or if the compressor won't come up to speed. Again depending on the model of module you should see an LED symbol silk screened onto the module case, showing you how to connect the LED.

Also, FWIW here's some stuff to think about if your fridge isn't even attempting to start.

I have encountered situations where the fridge doesn't even try to come on and it's sometimes caused by a dead thermostat. The Thermostat on a BD2.5 or BD3 system closes (shorts) to run and opens to turn off the fridge. If the fridge doesn't even try to run, disconnect the thermostat and short the wires at the thermostat. All of the thermostats that I have seen fail have failed in the OPEN mode, so the fridge won't even try to start when it gets warm. Note: With newer BD35 and BD50 variable speed compressors, there is a resistor in line with the thermostat. The value of that resistor sets the compressor speed (RPM). If you want to short out the thermostat to see if it works or not and you have a BD35 or BD50 compressor, make sure that you don't bypass the resistor. You can also easily check the thermostat by pulling the wires off of it (they are spade type connectors) and connecting an ohm meter to the thermostat and rotating the knob, checking to see if it opens and closes continuity appropriately. The module also contains a fuse. If the fridge doesn't even try to start, check the fuse and obviously check power too.

As I said, I am not a reefer expert at all I just figured out a few things that worked for me.

Best of luck!

CS
Last edited by carib sailor on Sun Aug 29, 2010 7:32 am, edited 1 time in total.

User avatar
maxicrom
admiral
admiral
Posts: 219
Joined: Fri Jun 06, 2008 12:29 pm
Location: II the Max (PDQ36 #12), Washington DC

Re: Fridge replacement

Postby maxicrom » Mon Aug 23, 2010 8:32 am

Along the same thread as CS,

A few weeks ago I heard our fridge clicking and not sounding normal - I did a quick check of my battery voltages on the panel and two of our batteries were showing 10.5 - 12v. A few weeks earlier I had noticed that our charger was running very warm and the locker was really warm, figuring it was due to the summer heat (it had been averaging 95 - 100 degrees every day over that time) I installed a heavy duty appliance timer to keep the charger off from 10am - 5pm during the heat of the day. The low voltage situation did not really show until an overcast day when the solar panels could not add the little extra to keep the fridge from making the noise. Anyway realizing that the issue was not heat, but my batteries, checking the electrolite with a meter showed that my main house batteries both had dead cells (I was hoping for corroded connections). The worst thing you can do to an electric motor is run it in a low voltage condition - with the cold plate system our house bank should run the fridge cycles for 7 hrs without issue. When I replaced the batteries I upgraded from group 24 to group 29 for a little more power, amazing the charger is not running hot anymore.

FYI: Our boat has two battery banks the STD 12v system and a secondary 24v system to power our Torqedo outboard (Stbd motor) - the timers seem to work well to provide a solid overnight charge to the house system and short maintenance cycle to the 24v system before the heat of the day. Both chargers are in the same STBD locker. I'm hoping the shorter high charge cycles will make for longer battery life.

good luck,

Mike
Mike & Linda
S/V II the Max

User avatar
holomoku
skipper
skipper
Posts: 61
Joined: Mon Jan 18, 2010 7:37 pm
Location: PDQ 36 Grizabella

Re: Fridge replacement

Postby holomoku » Mon Aug 23, 2010 1:28 pm

This has turned out to be a great resource....thanks all.

I plan to do some more troubleshooting this weekend.
I hope it turns out to be a bad fan.
I will check voltage as well and see what is going on there.
I installed new batteries in February this year so I'm hopeful that is not the issue.

If it looks like a bad controller, does anyone have a source for one?
The compressor is a Danfoss BD 2.5 (older unit, no longer produced)

Spencer

User avatar
holomoku
skipper
skipper
Posts: 61
Joined: Mon Jan 18, 2010 7:37 pm
Location: PDQ 36 Grizabella

Re: Fridge replacement

Postby holomoku » Sat Aug 28, 2010 5:53 pm

Well no simple fix here.

Tested voltage at the input to the controller. With batteries on charge (shore power) 13.4 v.
When the controller tries to start the compressor and beeps, voltage drops to 12.89v.
Fridge circuit is drawing 6 amps when trying to start.

Tried removing the fan and that had no effect.
I removed the connector from the compressor on the cable between the controller and compressor.
That eliminates the beep and current draw.
Fan performs erratically, never really spinning, but short turns every few seconds.

I'm guessing I have a controller failure or a compresor failure.
Either way, I'm inclined to upgrade rather that dump money into this old unit.
Thanks everyone for you advice and help.

James if you're out there give me a shout.

Thanks,
Spencer


Return to “Gear / Equipment / Maintenance”

Who is online

Users browsing this forum: No registered users and 2 guests