alternative kits for DIY compressor fridge

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pcatterall

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We are considering fitting an evaporator plate and compressor unit to an existing built in cold box.
Is there a cheaper alternate to the dometic range? I see that there are now Chinese alternatives to the Waeco stand alone chest coolers and wondered if there were kits around as well.
What are those special valves called that allow you to connect and disconnect the gas pipes without loosing gas?
 
pcatterall said:
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What are those special valves called that allow you to connect and disconnect the gas pipes without loosing gas? ...
Click to expand...
Leaks !

Ok a bit flippant, but self sealing couplings are just a slow leak.

It is presently unlikely that anyone will be importing ready charged equipment for boats, so even if you find a suitable item, you will still need someone to charge it for you. This means properly pressure testing, evacuating and then charging the system. All gases are becoming stupidly expensive and the regulations for who can use them (as in charge gas) are being tightened.

In my view not before time.
 
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I must be misunderstanding something then!! There are loads of DIY kits being sold ready gassed and with 'self sealing' connections. When I say 'self sealing' I may be using a wrong term they may be a 'one time' connector ( my term!) which can be 'made' once but then not reusable?
I understand that the regulations are being tightened which is great for the environment and also great for 'tradespeople' as well!
 
I've seen various adverts for a mini compressor unit (like this: https://www.alibaba.com/product-detail/Small-BLDC-Rotary-Refrigeration-Compressors_136562159.html). They look ideal for fitting to an existing cold box - most of the kits by Waeco etc. are complete overkill for what is required. Does anyone sell a complete kit incorporating these compressors? I agree with superheat6k that filling a system isn't a DIY job, and sourcing and matching evaporators and radiators and control units isn't simple, either.
 
pcatterall said:
I must be misunderstanding something then!! There are loads of DIY kits being sold ready gassed and with 'self sealing' connections. When I say 'self sealing' I may be using a wrong term they may be a 'one time' connector ( my term!) which can be 'made' once but then not reusable?
I understand that the regulations are being tightened which is great for the environment and also great for 'tradespeople' as well!
Click to expand...

As you say, there are plenty of ready charged units around and have been for many years, I installed mine about 8 years ago. The couplings have a valve and can be undone without losing gas if necessary.
 
All couplings loose a small amount of gas when split, even those with valves, more importantly they allow a small amount of air to enter when reconnected.
 
superheat6k said:
Leaks !

Ok a bit flippant, but self sealing couplings are just a slow leak.

It is presently unlikely that anyone will be importing ready charged equipment for boats, so even if you find a suitable item, you will still need someone to charge it for you. This means properly pressure testing, evacuating and then charging the system. All gases are becoming stupidly expensive and the regulations for who can use them (as in charge gas) are being tightened.

In my view not before time.
Click to expand...

My connections on my Beneteau are nearly twenty years old, the charge is still good, no leaks!
 
pcatterall said:
I must be misunderstanding something then!! There are loads of DIY kits being sold ready gassed and with 'self sealing' connections. When I say 'self sealing' I may be using a wrong term they may be a 'one time' connector ( my term!) which can be 'made' once but then not reusable?
I understand that the regulations are being tightened which is great for the environment and also great for 'tradespeople' as well!
Click to expand...
Pete
134a gas is still available occasionally on Ebay as well as mamifolds and guages, albeit at a price, not a difficult job for the DIYer to top up the system if necessary. Having said that the quick connect valves work ok, the action of joining them allows the internal pressure to keep air out of the system. Your comments about tradesmen hit the nail on the head!
 
pcatterall said:
We are considering fitting an evaporator plate and compressor unit to an existing built in cold box.
Is there a cheaper alternate to the dometic range? I see that there are now Chinese alternatives to the Waeco stand alone chest coolers and wondered if there were kits around as well.
What are those special valves called that allow you to connect and disconnect the gas pipes without loosing gas?
Click to expand...

I've not seen self-fit refrigeration kits like the online chandleries sell from China yet. There are some DC compressor units, but by the time you add an evaporator, condenser, thermostat, pipes, filter drier, fan, etc. you have not saved all that much versus a kit, and it's a lot more work, not to mention the hassle of then getting the thing filled with refrigerant . The bits for that will eat up the rest of your budget (vacuum pump, manifold, and the sometimes difficult to get refrigerant itself). More if you hire someone to do it.

The Danfoss/Secop BD35F (or larger BD50) unit is extremely common in fridges everywhere, and you can probably get a free one in fine working condition from a domestic (or boat) fridge someone threw out. Add the DC control box if it was an AC one (the compressor is the same). Still a lot of hassle to plumb your own piping, but that way at least you won't have the self-sealing connectors that seem to the cause of most boat fridge failures.

Lastly, you could possibly just get one of those standalone 12V compressor fridges from China, throw away the plastic bits and fit the rest in your ice box. Probably still involves cutting the pipes and then brazing them back together and regassing the thing though, so in the end not much saved either.

Or talk your favorite Chinese factory into making self-fit DC fridge kits for boats! :encouragement:
 
Each time you connect the o ring on the connector body seals a small amount of air in the fitting before it’s pushed fully home, unless you purge some gas out at the same time
 
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Daverw said:
Each time you connect the o ring on the connector body seals a small amount of air in the fitting before it’s pushed fully home, unless you purge some gas out at the same time
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Each time? Why would anyone want to keep disconnecting the pipework? Anyway, as pointed out above, the gas pressure is far higher than atmospheric so as the valve pin is depressed when connecting, a tiny amount of gas will purge any air from the fitting.
 
Daverw said:
Each time you connect the o ring on the connector body seals a small amount of air in the fitting before it’s pushed fully home, unless you purge some gas out at the same time
Click to expand...
Indeed.
But the system will cope with the very small amount of air involved.
 
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