Fridge Running Times

tgalea

tgalea

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Hi All,

This is my first summer with a BD35 and VD15 air evaporator fridge setup in our bavaria.

Temperatures in Malta right now are very hot, about 38 degrees inside the cabin and I find that our refridgerator is running for hours on end to keep the box cold. In the evening as the air temperature cools down a bit it start to cycle normally but am quite unhappy with the long running times during the day.

From your experience is this normal ? Do you experience this sort of problem or do i have a problem with my fridge ?

Another question; the fridge tech that came to check / service the unit in spring turned the condensor fan around so now it expells hot air from the condensor outwards towards the slatted vents in the cabinetry in front of it ?

Should i have the fun suck air in from the outside and blow it inwards towards the condensor ?

Your feedback would be appreciated.

Thanks
Tyrone
 
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What are you trying to get the fridge down to? You will be lucky to get a differential of more than about 25°C. Do you have any ice on the copper pipes near the compressor?

The fan should blow through the fins, preferably expelling the hot air. But is there somewhere else the cooler air can get in? I enlarged the slots in the front of the locker, and put vents between the two halves so air could get in via the other locker.
 
fridge running times

It is quite likely that the running times you are seeing are normal. However you get the same symptoms with a lack of gas so you can't be sure.
As said you may be asking too much on the thermostat. The cold plate may be iced up so insulating it from getting the cold to the fridge. Some people have reported huge improvements by fitting samll fan inside the fridge to circulate the cold. You may need more insulation on the fridge box or just be opening it too much or putting warm things into it.
You can however improve the cooling of the compressor and condensor. You need easy flow of air through the compartment and this may be improved with another fan. Old computers can be a source of low current 12v fans that work well. Or you can buy them cheaply. Don't forget the compressor itself will get hot and needs to be cooled as well as the condensor pipes and fins.
Do not just assume that the installer of the system did it in the most efficient way it is probably designed to be adequate for european summers not real summers. So you may be able to im-prove it a lot. good luck olewill
 
tgalea said:
Hi All,

This is my first summer with a BD35 and VD15 air evaporator fridge setup in our bavaria.

Temperatures in Malta right now are very hot, about 38 degrees inside the cabin and I find that our refridgerator is running for hours on end to keep the box cold. In the evening as the air temperature cools down a bit it start to cycle normally but am quite unhappy with the long running times during the day.

From your experience is this normal ? Do you experience this sort of problem or do i have a problem with my fridge ?

Another question; the fridge tech that came to check / service the unit in spring turned the condensor fan around so now it expells hot air from the condensor outwards towards the slatted vents in the cabinetry in front of it ?

Should i have the fun suck air in from the outside and blow it inwards towards the condensor ?

Your feedback would be appreciated.

Thanks
Tyrone
Click to expand...

We also have a Bavaria with a BD35 Compressor, but keel cooled, also very hot here at the moment, runs about 25% of the time in the day
 
William_H said:
Some people have reported huge improvements by fitting samll fan inside the fridge to circulate the cold...
Click to expand...

The VD-15 has a fan already. It's the same one that I have, but I've got a Waeco Series 90 unit with the larger BD-50 compressor, and I've lagged the copper pipes in the lower locker, and added 5cm of PE foam insulation in the top. On a day with an ambient temperature of over 32°C, I got the fridge down to 3°C, but I wouldn't consider running it this cold other than for testing; I consider around 10°C more than adequate.

I do have a project in mind to monitor and display the percentage run time, but it's way down the list at the moment.
 
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Different fridge but same system. As I'm in the UK we obviously have lower temps. However we were on the boat for 2 week of 30C+ temps last year and had a similar problem. We changed the compressor layout to get the maximum airflow possible over the heat exchanger. This helped but needed the door to the locker to be kept about 3cm ajar during the daytime to improve airflow further. This did the trick even on 1 day when the temp hit 35c
 
brendanbergin said:
As I'm in the UK we obviously have lower temps. However we were on the boat for 2 week of 30C+ temps last year ................... This did the trick even on 1 day when the temp hit 35c
Click to expand...

Which bit of the UK was this? :eek: You sure you didnt put C instead of F?

My boat has a similar compressor set up but with fridge and compressor all inside the galley unit so the hot air from the compressor is circulating round the outside of the insulated ( ha! ha!) box . Result - 5 amps draw when running and running about 40% of the time even in this joke of a summer.

The real answer is lots of insulation and in a factory built boat you wont get that. In my Prout cat when I had it there was more than 12 inches of foam on some sides of the box and I had the reverse problem of freezing the contents if I didnt watch out.

Direction of the draught through the radiator shouldnt matter very much.
 
I think everyone has the same problems. We have a cat, which I think allows an easier solution. We could run a duct from our anchor locker straight into the locker where the fridge compressor was located, we added a fan to the end of the duct, so the fan drew air into the locker from the anchor locker and directed the air directly onto the fridge compressor. We added another fan to get the air out of the locker - as suggested 2 low power computer fans off old computers.

Think of whether you can add ducting, that spiral stuff used for kitchen hood extractors (we actually used drain pipes) from outside and get it into the locker where your compressor is located. There must be a vent in your locker, duct to get the air out and help it by adding a fan. After that, can you add extra insulation.

Good luck
 
Thank you all for your replies.

I will adjust the thermostat to a slightly warmer temperature and see what happens. I had a Carel digital thermostat installed and the sensing probe is about 1/3 down from the top.

with a cabin temperature of 35C the sensing proble is reading 12C after hours of running. Of course the bottom of the box would be cooler.

The temperature inside the box is cold enough for us, i mean the food and drinks are cold it is just the running time and hence daily amp hour consumption that is worrying me.

I know the previous owner had done the mistake of allowing a tech to connect gauges to the system, and i did a second mistake of allowing the same tech the opportunity to connect gauges once again!

I'm concerned it could either be under gassed or over gassed. I will investigate further and let you know.

thanks
Tyrone
 
vyv_cox said:
Look at http://coxengineering.sharepoint.com/Pages/Refrigeration.aspx for guidance about under and over gassing. Sorry the photos have not yet been replaced on this page but all the text is complete.
Click to expand...

Interesting:

Slightly overcharged system

Too much refrigerant in the system will result in liquid still evaporating back to a gas past the end of the evaporator and inside the tubing going back to the compressor. This means that there is still some of the refrigeration process going on inside the tubing and there will be a build-up of frost or ice on the exposed section. If additional insulation has been added, it may be concealing this symptom and should be removed. The evaporator may appear and sound normal, but will be at a higher temperature than desired, resulting in longer than expected run times.

I used to get ice on my return pipe, so I added insulation. I installed it as a pre-sealed system (and I got a leak for a second or so while I grabbed a spanner) so I don't see how it could be overcharged. Should I let some more gas out?
 
wotayottie said:
Which bit of the UK was this? :eek: You sure you didnt put C instead of F?

My boat has a similar compressor set up but with fridge and compressor all inside the galley unit so the hot air from the compressor is circulating round the outside of the insulated ( ha! ha!) box . Result - 5 amps draw when running and running about 40% of the time even in this joke of a summer.

The real answer is lots of insulation and in a factory built boat you wont get that. In my Prout cat when I had it there was more than 12 inches of foam on some sides of the box and I had the reverse problem of freezing the contents if I didnt watch out.

Direction of the draught through the radiator shouldnt matter very much.
Click to expand...

I'm telling it like it was but I do agree that good insulation made a difference. The compressor location is not in the galley area as it was too warm - we located it in a cooler locker. And also the plate is not enclosed as we do not especially want ice - I'd prefer the cold air to circulate around the whole box.
 
nigelmercier said:
Interesting:

Slightly overcharged system

Too much refrigerant in the system will result in liquid still evaporating back to a gas past the end of the evaporator and inside the tubing going back to the compressor. This means that there is still some of the refrigeration process going on inside the tubing and there will be a build-up of frost or ice on the exposed section. If additional insulation has been added, it may be concealing this symptom and should be removed. The evaporator may appear and sound normal, but will be at a higher temperature than desired, resulting in longer than expected run times.

I used to get ice on my return pipe, so I added insulation. I installed it as a pre-sealed system (and I got a leak for a second or so while I grabbed a spanner) so I don't see how it could be overcharged. Should I let some more gas out?
Click to expand...

I am no expert on the subject but my son Owen is. Suggest you PM him your question. He is going on holiday tomorrow and probably will not be reading this but he should receive PMs. Owen-Cox.
 
What age is your Bav? I have a Bav44 year 2002 and spent 5yrs in the Med with it. Had similar problems that you described. Some of the replies fit the symptoms and solutions I arrived at. I wrote a 'thesis' on the subject back then to log my work. I'd be happy to send it to you. It is a combination of improving the insulation and the internal fridge 'box' air circulation. After my mods the on time was only 25-30% even in the hottest weather.

However, no miracles promised.

Ray
 
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