R-134a standard automotive fitting to 1/4 male fitting?

[msulc]

Hi, From what I have read about the frosting on the evaporator plate, I think I need to add a little R-134a to my danfoss freezer compressor.

Is there a place I can order the adapter from the standard automotive connection you can by at automotive stores to the 1/4 SAE Male flare on the danforth compressor that I need to use? Are there regular stores that stock this? Pep boys didn't seem to have what I needed.

Thanks!!!

[s/v Jedi]

The Danforth compressors come without any installed fittings, so it is the company who converts them for use on boats that install these. What brand is yours and are you sure that your service valves are SAE flare fittings?

AFAIK most Danfoss compressor solutions have the Schrader valves (look like car tire valves) that most gauge sets can directly connect to. My Frigoboat units have these too.

ciao!
Nick.

[msulc]

Hi Nick, I have the Nau-t-kol Stone Cold reefer. The manual says it has a 1/4" standard male fitting. It does look like a car tire valve.

Is there an adapter for this or do I need to get a gauge set?

Thanks!

[s/v Jedi]

Originally Posted by msulc

Hi Nick, I have the Nau-t-kol Stone Cold reefer. The manual says it has a 1/4" standard male fitting. It does look like a car tire valve.

Is there an adapter for this or do I need to get a gauge set?

Thanks!

Yes, it's a 1/4" Schrader valve. I always use a gauge set for topping up. Let me give some tips here:

- purge hoses with a little refrigerant

- an empty system: switch system off; open both high side and low side valves; open valve on refrigerant tank; let refrigerant equalize between tank and system; gauges show building pressure; when equalized, close both high and low side valves

- start system; let it run for a couple of minutes and check evaporator plate for frost. The _whole_ plate must be frosted; if not, open the low side (suction side) valve on the gauge set to allow some extra refrigerant into the system; close after 5 secs; test frosting again and repeat until fully frosted.

- as box temperature comes down, so does the pressure inside the system (refrigerant shrinks) and you must add more refrigerant to keep the evaporator fully frosted. Keep at it until the thermostat switches the system off.

- at this point (when compressor starts running again) I add some extra refrigerant so that I see frost on the copper tubing for about a foot of length from the evaporator. This provides some buffer.

- keep in mind that when you sail from tropical to moderate climate you need more refrigerant and vica versa.

So, for filling a Danfoss based system, use the frost on plate and tubing as indicator of charge, not a gauge reading.

ciao!
Nick.

[msulc]

Thanks for the tips!!! Do you think a set like this will have to correct adapters for the unit?
Mastercool 89660 R-134a Aluminum Gauge Set in Case#

[s/v Jedi]

Originally Posted by msulc

Thanks for the tips!!! Do you think a set like this will have to correct adapters for the unit?
Mastercool 89660 R-134a Aluminum Gauge Set in Case#

yes, no adapters needed; the hoses fit on the Schrader valves.

ciao!
Nick.

[AllezCat]

Actually I had to do the same thing.
The stuff they sell at the auto stores has a different fitting than the regular refrigeration fittings and gauges...
You will need an adapter - if they sell them...
I ultimately got my EPA license and bought the stuff at a refrigeration store.
(amazing they sell some gas to the general public in the auto section)

[AllezCat]

I checked that link at it does include an adapter from automotive cannisters to regular refrigeration tanks, hoses/Schroeder valves, etc...

[s/v Jedi]

Originally Posted by AllezCat

The stuff they sell at the auto stores has a different fitting than the regular refrigeration fittings and gauges...
You will need an adapter - if they sell them...

Originally Posted by AllezCat

I checked that link at it does include an adapter from automotive cannisters to regular refrigeration tanks, hoses/Schroeder valves, etc...

Ah, with "stuff" you mean the R-134a refrigerant in the small canisters! Yes, the screw & puncture valves for these have a different thread and don't fit the yellow hose of an R-134a gauge set. The kit linked has a clamp & side-puncture thinghy for these canisters. When they sell this as a kit, one can only assume the adapter comes with it :-)

ciao!
Nick.

[msulc]

Thanks again! They have this kit at advanced auto parts. I will give it a try this weekend.

What do you do with any extra refridgerant? Do you just keep it in the can with the clamp on it? Seems a little dangerous for a boat...

[meyermm]

Not sure of the system you are trying to fill but if its empty all the refrigerant systems I have worked on require evacuation via vacuum pump to purge air and moisture from the system prior to recharge. Also overcharging can cause expensive problems so knowing the system capacity (R134) would also be a good idea. Obviously the US regulators are much more lax in there ozone protecting rules and regulations than here in Oz but thats another story.

[s/v Jedi]

Originally Posted by msulc

What do you do with any extra refridgerant? Do you just keep it in the can with the clamp on it? Seems a little dangerous for a boat...

Yes, just keep that clamp on it. R-134a from that little can poses no danger to you or your boat. My Frigoboat units (Danfoss BD50 based) + keelcooler + evaporator plate take less than 1 canister each. If you have long lengths of pipe to/from the evaporators you might need more. But, this is for an empty system!

Originally Posted by meyermm

Not sure of the system you are trying to fill but if its empty all the refrigerant systems I have worked on require evacuation via vacuum pump to purge air and moisture from the system prior to recharge. Also overcharging can cause expensive problems so knowing the system capacity (R134) would also be a good idea.

A contaminated system must be evacuated yes. I believe the OP is just "topping up". If Richard Kohlman would have read this before me, he would have replied that you must find the cause of the disappeared refrigerant so that you can fix that. He is right of course. For me, it turned out to be the O-rings in the quick-connect fittings.

On overcharging: if you do it the way I described you will not overcharge the system. Checking the frost is the best way for systems without an accumulator (thank god I got rid of that old system :-)

ciao!
Nick.

[sfnz]

the fitting on the can will be acme male, you'll need a female acme> 1/4"male flare to connect,
to charge, add gas , enough to keep it around 30ishPSI when gauge is off (assume you are single port filling here) then turn compressor on, watch gauge sink to about 10PSI crack gauge to add and maintain the 10PSI and periodically turn gauge off, when it'll maintain the 10PSI mark with the gauges off and the unit running you're getting pretty close...........patience is the key here in a freezer application you'll be looking at 0>1 or2 PSI on the gauge as the unit cycles off, more for a fridge. Frigo do send units out over charged , they're also renowned for units that produce excess head pressure due to insuficient vacuum, best thing to do I've found is to bight the bullet, weld out the connectors and evacuate overnight to have a truely troublefree system

[sfnz]

one other thing to add here, those auto cans of 134a need a wipe of either grease or lanacote to keep them corrosion free particularly where the valve connects, and a spot of something to lubricate the seal when you connect is a good idea as well, you could be ultra purist and use polyolester oil but the reality is that anything'll work as long as it is a wipe and not a blob

[msulc]

I guess I am a little confused about the fitting. The fitting I saw at the store seemed to be a female acme and the fitting on my unit is a 1/4 sae male.
So the adapter should be a male acme on one end and a female 1/4 sae on the other. Right?

I am definitely going to try to figure out where a leak might be. We had issues with our refrigerator before (the second issue in 2 years) and the second guy said one of the bolts was loose that might have caused it to leak. It was pretty upsetting to pay someone a load of money to basically refill the r134a and then have to call someone a year and ½ later.

I will check the freezer and hopefully it is something similar. It is still working, just not getting as cold as it should and is now running constantly. It has been fine for the last two years since we bought the boat in hotter and cooler environments.