High refrigerator power draw

[crayiii]

We have a top loading vitrifigo freezer with a BD50F compressor that has been in the boat since 2017.

In the past, it's used about 5 amps when running.

We recently purchased a Engel portable unit and use that as our freezer. We turned the thermostat on the built in as low (warm) as it will go and have been using that as a second refrigerator.

Since we've done that, it seems to take a lot more amps when running. I've seen 8-10 amps when placing a clamp on it.

Is that a byproduct of having it at the lowest setting it is something else going on with it?

Do I need to replace the compressor and thermostat if we want to o use it as a refrigerator long term?

[capt jgw]

Could you have been reading startup load? On "freeze" it's probably running most of the time, so once it's running you'll only see the continuous load. On the warmer setting it will start and stop often, and a startup load can be twice the continuous. There's two or three motors in these things and they take a lot of power to get rolling.

[Lepke]

The entire freezer, coils, compressor, etc., was designed to freeze. If it maintains the temp you want then it would do no good to replace parts until they fail. And then you'd be better off to buy a reefer that fits in the space. The load on the existing components should be less than when used as a freezer, but it will not be as efficient.

Motors draw more amps when the load is increased, bearings are failing, causing a drag the motor must overcome, or low voltage. Lower the voltage, higher the amps.

[crayiii]

Originally Posted by Lepke

The entire freezer, coils, compressor, etc., was designed to freeze. If it maintains the temp you want then it would do no good to replace parts until they fail. And then you'd be better off to buy a reefer that fits in the space. The load on the existing components should be less than when used as a freezer, but it will not be as efficient.

Motors draw more amps when the load is increased, bearings are failing, causing a drag the motor must overcome, or low voltage. Lower the voltage, higher the amps.

Voltage was over 13 at the unit when I checked today. It is making a growling sound though...

[Richard Kollmann]

[QUOTE=crayiii;3251499]We have a top loading vitrifigo freezer with a BD50F compressor that has been in the boat since 2017.

In the past, it's used about 5 amps when running.

We recently purchased a Engel portable unit and use that as our freezer. We turned the thermostat on the built in as low (warm) as it will go and have been using that as a second refrigerator.

Since we've done that, it seems to take a lot more amps when running. I've seen 8-10 amps when placing a clamp on it.

Is that a byproduct of having it at the lowest setting it is something else going on with it?

Do I need to replace the compressor and thermostat if we want to o use it as a refrigerator long term?[/QUOTE
If you are sure you are using clamp on Ammeter correctly then 8 amps ten minutes after compressor is running is excessive. A properly cooled BD50 compressor under normal loads will draw at most 6.5 amps and much less just before thermostat cycles compressor off. If no one has tampered with refrigerant I would suggest you see if condenser cooling is free of dust and other material and take steps to increase condensing unit's cooling.

[Junk Viking]

Originally Posted by crayiii

. . .

Since we've done that, it seems to take a lot more amps when running. I've seen 8-10 amps when placing a clamp on it.

Is that a byproduct of having it at the lowest setting it is something else going on with it?

Do I need to replace the compressor and thermostat if we want to o use it as a refrigerator long term?

NO
Nothing is (likely) wrong with your compressor.

The increase follows normal physics, as compressor capacity goes up when it has to handle a lower temperature difference.
Capacity has gone up, and so did efficiency while running time has dropped significantly.
Thus total energy consumption has also gone down.
Check the spec sheet, and you can see for your self:
https://assets.danfoss.com/documents...5586436530.pdf

You may be able to reduce energy consumption even further, depending on your installation.
The aim is to reduce compressor speed and increase % running time.

A well designed appliance will do this by it self.
A simple installation may have a resistor on the Electronic unit that sets the speed.

This is all described on the spec sheet.
Basically you can try detaching the resistor - that should drop the speed to 2000RPM - the lowest possible.

Good luck

Peter
Spent 5 years designing cold appliances including using the DB series.

[Richard Kollmann]

Continuing to run compressor at those condenser high temperatures will cause module failures and possible refrigerant contamination system failures. Lowering compressor speed is only a ban dad solution unless that unit uses an expansion valve refrigerant flow control device instead of a capillary tube.

[crayiii]

I tracked it yesterday and it ran for 22 minutes and didn't run for 2 hours. That cycle continued throughout the day. We're anchored waiting for weather to head south around Hatteras so I'm bored. ��

The draw starts at 8-10 amps but then gradually decreases to 6 before it shuts off.

[crayiii]

I removed this board from between the thermostat and the T connector and now the unit only took 3.8 amps when I plugged it back in (it's been unplugged for a couple of days. The resistor says 122 on it and the multimeter showed 1.2

Did this fix it or by having the unit off for a few days make this change?

[Bycrick]

A resistor marked "122" should have a nominal resistance of 12 followed by 2 zeros, or 1200 ohms. A reading of 1.2 on a digital meter mean that the meter is reading in Kohms, or thousands of ohms, so 1.2 Kohms = 1200 ohms.

[Richard Kollmann]

The resistance between module terminals C and T will determine compressor running speed, NO resistance compressor speed is 1,000 Rpm drawing 3 plus amps. Maximum design speed of this compressor is 3,500 Rpm with thermostat wiring resistance in the circuit of 1,500 ohms.
Best energy Coefficient Of Performance (COP) for your unit would be when compressor runs less than 50% of the time and still satisfies desired box temperatures. Compressor may run longer at a slower speed but at a greater efficiency.

[crayiii]

After running it this way, it used much less power while running but it never turned off because the thermostat is for a freezer.

I just replaced the freezer thermostat for a refrigerator thermostat but the capillary tube on the new thermostat was much shorter.

The original tube went from the thermostat mounting location on the inside too of the box, out a hole down the outside and into a small copper tube at the bottom of the box. Presumably, where the plate is.

Since the new one was much shorter, I have coiled it up inside the box.

Is this going to work okay?

[crayiii]

Fixed