Thanks Richard - After posting here, I found you site and repeated the
question there, but in more detail.

Low voltage is unlikely because batteries were freshly charged - could be a
bad connection somewhere - I will check. High/Low voltage is possible if an
input range of say 110-120v does not result in 24V within the cutin/out
range.

Fan circuit overload is possible - I added some insulation above unit -
maybe something dropped into fan - I will try vacuuming. I will also try
disconnecting the fan.

I will also try and get an ammeter installed - I don't like the idea of
adding more connections though - Maybe I can get a clamp on type.

Funny thing though, once unit does start, it keeps running, so you would not
think there could be an overload.

I will post this reply to your site too and perhaps we can move discussion
there?

GBM

wrote in message
oups.com...
GBM, Low voltage is the most common cause of start up problems. Low
voltage can be traced to low battery voltage or the boat's electrical
circuit. The only way to insure that it is not a voltage problem is to
connect a full charged battery directly to the electrical module with
proper sized correct polarity jumper cables. The older model BD2.5 and
BD3 compressors can indicate a low voltage fault with a LED if one is
installed between module terminals C and D. Newer compressors BD35 and
BD50 have a full function computer chip like your automobile. You can
learn more about LED trouble shooting by viewing the slide show on my
web site at http://www.kollmann-marine.com. There are several sections
on all these compressors also in my 12/24 Volt Refrigeration Manual.

The fan circuit overload will stop the compressor if the fan is faulty.
There is a separate set of 12 volt + and - terminals on the module that
powers the fan even it compressor is running on 24 volts, for cooling
when the thermostat closes. This fan circuit on older units is limited
to a maximum of one amp and ½ amp on BD35 and BD50 compressor modules.
To eliminate this circuit as a cause for a false compressor start,
disconnect the fan wires and any other units connected to these
terminals. When eliminating the fan make sure that the thermostat wire
is not removed from C terminal on the older models.

High amperage overload: The first thing to check is to see that there
is adequate air flow through the condenser coil, see if the fan is
running or could dust be blocking the coils. To test for overload
connect a 10 amp scale ammeter in series with the power wire to the
module and watch the start up and running amps. If the start amps
exceed 9 amps or the running amps are above 7 amps, when operated on 12
volts, there is an overload. An amperage overload indicates the
compressor is faulty or if recently serviced with refrigerant there is
a refrigerant problem.

The module is more likely to fail than the Compressor but WARNING, do
not install a new module on a compressor that test bad with the ohm
meter.

GBM wrote:
Thanks Richard - After posting here, I found you site and repeated the
question there, but in more detail.

Low voltage is unlikely because batteries were freshly charged - could be a
bad connection somewhere - I will check. High/Low voltage is possible if an
input range of say 110-120v does not result in 24V within the cutin/out
range.

Fan circuit overload is possible - I added some insulation above unit -
maybe something dropped into fan - I will try vacuuming. I will also try
disconnecting the fan.

I will also try and get an ammeter installed - I don't like the idea of
adding more connections though - Maybe I can get a clamp on type.

Funny thing though, once unit does start, it keeps running, so you would not
think there could be an overload.

I will post this reply to your site too and perhaps we can move discussion
there?

GBM

My site and mail is off for a couple of hours on Sundays so I will
answer your questions here.
1. If you disconnect shore power from boat the question of high voltage
will be eliminated. The BD35 Module can except voltages up to 29 volts
before it shuts down compressor.
2. I have no information on Mobiletronics's inverter or how it is
wired to the Danfoss module. If one of the safety perimeters of module
is being violated there will be a single audible beep coming from
module. Is there a beep sound when unit is turned on and unit does no
run? Does fan run even if unit does not run?
3. Terminal P on module is only used if low voltage cutout is to be
increased so if there is a wire on P terminal remove it and tape the
lose end.
4. The only wire to be connected to Module terminal D is a ground wire
from troubleshooting LED and that ground is only activated when a
module parameter is exceeded. One flash of LED indicates low voltage,
Two flashes a fan problem and so on. Low voltage on start may not be
detectable with a meter unless you have Superman's eyes. Any
resistance connection in wiring anywhere between module and battery
will signal module to abort when current starts to flow, that why I
recommend by passing all wiring.

Correction to my first post the LED on older compressors is connected
to terminals C and D but on BD35 and BD50 compressors it is connected
to the small + terminal and the D terminal.

wrote

Thanks for the reply Richard.

1. If you disconnect shore power from boat the question of high voltage
will be eliminated. The BD35 Module can except voltages up to 29 volts
before it shuts down compressor.

Yes - If battery charger is the cause this will help. Unit should run OK on
Mobitronic unit and has in past - But I need to do some detailed testing.

2. I have no information on Mobiletronics's inverter or how it is
wired to the Danfoss module.

FYI - The Waeco Mobitronic rectifier accepts 110V and puts out 24V nominal.
When AC is present, a solenoid acitivates which switches off DC battery
power. The DC power from the battery runs to this unit and then on to the
refrig unit Here are some links - I suppose it is possible that this unit
has a fault, because even DC from battery goes through it's internal switch.

http://makeashorterlink.com/?T1782437D

http://www.waeco.biz/tmp/MPS-35_B_d_gb_04.pdf

If one of the safety perimeters of module
is being violated there will be a single audible beep coming from
module. Is there a beep sound when unit is turned on and unit does no
run? Does fan run even if unit does not run?

I have not heard a beep and fan does not run. Unit just seems to go into
hibernation, but then it eventually wakes up after temperature in box has
risen 10F or more.

I see your site is back on - I will post later after I go down to boat.

GBM