12v Shoreline fridge

[nicknorman]

Our 12v Shoreline fridge is 10 years old now, but as leisure boaters its probably only been used for an equivalent of 3 years. And very expensive it was too!

Over the last year or so I've noticed its been running a lot, so I did some investigations:

 

After we had been on the boat for a few days (so the fridge was cold and stocked with cold food) I connected an hour meter to the fan output to check the actual running time. Over 3 days (72 hours) it ran for 56.8 hours, so an average duty cycle of 79% which seems high bearing in mind average ambient cabin temperature around 18-22C.

 

Door seals seem fine and there is not an excess of ice formation inside. There is an adequate ventilation air gap all round and above the outside of the fridge, and anyway the casing doesn't  get warm (its the type with no visible radiator at the back).

 

The thermostat is on setting 3 and the fridge temperature in the middle is 4C, in the ice box it is -21C, so the fridge is cooling adequately but at the expense of the compressor running for most of the time (and obviously using electrical power when it does so). I'm sure it never used to run this much.

 

So it seems to me that either the compressor is ineffective, or there is a lack of refrigerant or a blockage. Bearing in mind that although the fridge is now 10 years old, we only use the boat for leisure and so at the most the fridge has been switched on for perhaps the equivalent of 3 years, I would hope the compressor isn't worn out.

 

Any thoughts? Does it just need re-gassing?

[Alan de Enfield]

Just for a comparison - when I installed my (new) Waeco 12v fridge, on temperature 'setting 3' it ran approximately 20 minutes in the hour, but was very dependant on the number of times the door was opened.

[Tracy D'arth]

It may well be short of gas.

The ones with no condenser on the back do not inspire confidence in me. Unless there is a large air gap at the sides they tend to heat the cavity rather than the circulating air outside.

They are also impossible to repair if the leak, no matter how small, is in the insulated sides.

 

[nicknorman]

5 minutes ago, Alan de Enfield said:

Just for a comparison - when I installed my (new) Waeco 12v fridge, on temperature 'setting 3' it ran approximately 20 minutes in the hour, but was very dependant on the number of times the door was opened.

Thanks. 33% duty cycle is what I would expect. I think we don’t open the door excessively, and certainly it remains closed for around 12 hours over night between dinner and breakfast.

Just now, Tracy D'arth said:

It may well be short of gas.

The ones with no condenser on the back do not inspire confidence in me. Unless there is a large air gap at the sides they tend to heat the cavity rather than the circulating air outside.

They are also impossible to repair if the leak, no matter how small, is in the insulated sides.

 

I presume the condensed (radiator thingy) is thermally connected to the side of the fridge casing. There is at least 15mm clearance at the sides and loads at the top. When I pull the fridge out the casing doesn’t feel at all warm, it is at ambient temperature as close as a hand can judge.

[BEngo]

The ice box is getting  too cold.  It should be only -18C for a 4* freezer and -16 C for a 2* (which I think is what Shoreline  claim it is).

I think if you can get the icebox that cold you must be OK for gas.  Shortage of refrigerant would give you a high temperature in the icebox.

 

The cold icebox/correct fridge  temps  indicates the stat is Ok but the cold cupboard bit is not getting good internal air circulation from the evaporator/icebox.  Have you got the variety with the plastic tray under the ice box and a flappy bit at the back of the tray?  If so fold the flap into the tray to let more cold air fall off the evaporator and try again.

Also try to arrange the tinnies etc. so that the cold air can drop easily away from the icebox.

 

You could ask Shoreline their opinion.  Last time I sent them  a tech query I had a useful and fairly detailed reply within the hour.

 

N

[TheBiscuits]

My fridge did exactly that then went to 100% running and no cold.

 

A regas fixed it back to running 20 minutes in the hour and cold again.  

[Tracy D'arth]

Failing to defrost leads to extended run times.

[nicknorman]

Just now, Tracy D'arth said:

Failing to defrost leads to extended run times.

True, but the fridge was only switched on a week ago.

[WotEver]

I guess at 10 years old a teeny tiny hole would allow just enough gas to escape to lengthen the run time.  Having said that, @BEngo's post appears to have a lot of merit, and it's free to experiment with the loading of the contents.

[Tracy D'arth]

3 minutes ago, nicknorman said:

True, but the fridge was only switched on a week ago.

Its been a bit damp this week!   Possible not then, I know that if I fail to defrost mine every 2 weeks, it runs longer.

Edited August 28, 2020 by Tracy D'arth

[Rob-M]

Our Shoreline fridge seemed to run excessively when we were out in June but it was during the hot spell. This last week it doesn't appear to be running as often or as long. It does seem to run more when there is a lot of food in the fridge.

[OldGoat]

These ex-Lec (or equivalent cases that Shoreline now use) are not the most efficient devices around, being built down to a price, rather than for efficiency. 

The atmosphere inside a boat has more water vapour than in domestic premises - and that means the inside is more prone to icing up.

The net result is that whatever 12/24 fridge you use is going to be relatively greedy of energy and if you have two (fridge and separate freezer under counter units )  even more greedy.

 

My Lec-Batts unit is now some 20 years old, the seals are bad and the 'internal furnishings' are rusty but as The Management says it does the job. I have a Liebherr 240V A/C replacement that is much better designed and with a high A rating should cost at least the same - if not better - battery consumption than the LEC. It might even (watch for flying pigs) be not too greedy after the inverter base running power is taken into consideration.

 

The only delay for me is getting off my 'fundament', loading it into my trailer, lugging it down to the marina and loading it through the side hatch (Liebherr say it must be upright at ALL TIMES anything else is Streich Verbotten under any circumstance...

  

[WotEver]

12 minutes ago, OldGoat said:

These ex-Lec (or equivalent cases that Shoreline now use) are not the most efficient devices around, being built down to a price, rather than for efficiency. 

I suspect Nick knows all that and has a hefty Inverter anyway, were he to change.  He's simply asking "Why has it changed?"

[nicknorman]

3 minutes ago, WotEver said:

I suspect Nick knows all that and has a hefty Inverter anyway, were he to change.  He's simply asking "Why has it changed?"

Yes, I would prefer to fix the existing fridge but if I can’t, we’ll be getting a mains fridge.

[OldGoat]

3 minutes ago, WotEver said:

I suspect Nick knows all that and has a hefty Inverter anyway, were he to change.  He's simply asking "Why has it changed?"

'Twas not an attempt to solve Nick's issue, but more pro bono for those who read through threads looking for info on 12V versus 24v refrigeration. Fred Drift rules....

[WotEver]

1 minute ago, nicknorman said:

Yes, I would prefer to fix the existing fridge but if I can’t, we’ll be getting a mains fridge.

I'll be interested to find out if rearranging the contents has any effect.

[nicknorman]

2 minutes ago, WotEver said:

I'll be interested to find out if rearranging the contents has any effect.

I can’t see that it will. Over the time that I’ve noticed the excess running (most of last year and all of this) the fridge has been loaded anywhere between virtually nothing and rammed full.

[Alan de Enfield]

8 minutes ago, OldGoat said:

looking for info on 12V versus 24v refrigeration.

 Just for those looking for comparisons in the future - are we missing a "0" ?

Edited August 28, 2020 by Alan de Enfield

[OldGoat]

14 minutes ago, Alan de Enfield said:

 Just for those looking for comparisons in the future - are we missing a "0" ?

lordy, lordy - yes - loads of missing '0' (zeros).

(grovel implied) - though I doubt if anyone (apart from your good self) would have read my submission.

 

However, 'one' has to try??

[Sea Dog]

39 minutes ago, nicknorman said:

I can’t see that it will. Over the time that I’ve noticed the excess running (most of last year and all of this) the fridge has been loaded anywhere between virtually nothing and rammed full.

Nick, I note your static +4 and -21 figures, but have you had a look at what it's doing upper and lower temperature wise with a max - min thermometer overnight when it's not being opened and closed? Could a cycle of over warming and over cooling be responsible for it having to work too hard? Just a thought.

[Tracy D'arth]

A fridge thermostat has a deliberate hysteresis tailored to the insulation value and volume of the cabinet. If this gets altered by age or damage to the phial on the thermostat it could be that the performance of the fridge will be substantially changed  adversely.

[dmr]

I believe there is only one thermostat and that does the fridge, then it hopes that there is enough running to keep the freezer section cold. This is why they defrost the freezer in winter if the boat gets too cold, just not enough running.  The fact that your freezer is very cold could be because the compressor is running too much so it does suggest that everything is working. Question is why so much running to get the fridge at its correct temperature? Are you 100% sure the door is shutting and sealing well?  I would say thermostat but if that was the case then why is the fridge not extra cold???

I was told by a (dis) reputable fridge "engineer" that the insulation degrades badly over time, but I did say dis reputable.

 

................Dave

[Tracy D'arth]

2 minutes ago, dmr said:

 

I was told by a (dis) reputable fridge "engineer" that the insulation degrades badly over time, but I did say dis reputable.

 

................Dave

Only if it gets wet. The foam does out-gas for years but the insulation U value remains fairly constant.

[Cheshire cat]

You'll have to keep it for a while Nick. I was curious regarding energy consumption on a 240 Volt fridge.  A++ rated fridges use only half the energy of A+ fridges but there's not much to be had. Mostly out of stock.  92Kwh versus 182Kwh

 

Do shoreline give any figures for their 12 volt fridges I wonder. Ours is an antique, coming up to its 21st birthday.

[johnmck]

Just replaced the thermostat in our integrated shoreline fridge and added an additional fan for hot (haha) weather running . The additional fan is switched.  The new thermostat has reduced run time, but I think the original fan is also u/s. I will try replacing this also. More a noise thing than operation, as it does operate within parameters.