1995 Catalina 42 Adler Barbour fridge advice

[JlewCat42]

Hi,
I’m new to the forum and looking for some advice. I’ve a Catalina 42 Mk II and I’m having problems with my fridge. The compressor runs file, but the cold plate is not getting cold. It is getting some condensation on the plate which makes me feel that its operating but its a coolant issue. The systems takes R-134a. I’ve looked at the compressor and researched adding coolant to the system. Advice talks about adding through the suchion / low pressure port. However, I can’t find a description / diagram to identify which is the low pressure port. One value is at the end of a short pipe coming out of the main ‘flask’ of the compressor, the other seems to be between the ‘grill’ and one of the pipes leading to the cold plate. This second one is on a ‘T’ joint . At the bottom end of the ‘T’ joint is a white canister. I’ve also read about purchasing a recharge host & gauge (+ can of 134a) from an auto parts store.

Any suggestions please ?

Thanks in advance

 

[Stu Jackson]

The first place to go is here:

http://www.kollmann-marine.com/

You can ask there, too. Good luck.

 

[justsomeguy]

I’ve also read about purchasing a recharge host & gauge (+ can of 134a) from an auto parts store.

That's how it's done.
Loosely attach the connector to the Schraeder valve, purge the hose and valve of air and then tighten the connector to the valve. Keeping the can of 134a upright, squirt a bit in, wait awhile and check the evap plate for a higher level of frosting. It took me a couple of hours to incrementally top off my AB Super Cold to where the evaporator was almost totally frosted over.
Too much coolant is a no-no. You don't want frost forming on the supply tubes leading to the evaporator plate.
Kollman's site is excellent.

 

[JlewCat42]

The first place to go is here:

http://www.kollmann-marine.com/

You can ask there, too. Good luck.

Thank you for post.. will try there.

 

[JlewCat42]

That's how it's done.
Loosely attach the connector to the Schraeder valve, purge the hose and valve of air and then tighten the connector to the valve. Keeping the can of 134a upright, squirt a bit in, wait awhile and check the evap plate for a higher level of frosting. It took me a couple of hours to incrementally top off my AB Super Cold to where the evaporator was almost totally frosted over.
Too much coolant is a no-no. You don't want frost forming on the supply tubes leading to the evaporator plate.
Kollman's site is excellent.

Great thanks... pulling it all together
I’d read about greadually introducing the 134a and letting the system settle down and especially not adding too much.. thanks..

 

[JimInPB]

The "cold plate" is on the low pressure side. That is where you add refrigerant.

Somewhere in the system, there is probably some sort of canister that can be removed. It is often just after the high pressure "grill". That canister is going to be the receiver/drier. Normally, if you need to add refrigerant, it is prudent to also consider replacing the drier canister. Moisture in the system will eventually become part of a chemical reaction that results in "the black death", which is a corrosive event that ruins all the major components in the whole system. The drier removes moisture from the system & suspends it in a descant. The descant has a limited capacity to hold moisture. Once it is saturated, it stops working. If the resting pressure in the system was down past about 20-40psi (depending on the system) at any time, there is a good chance that moisture got sucked in through the leak. Technically, you are supposed to draw the whole system down to perfect vacuum & hold it there for a while before recharging, to be sure that moisture is not present. That requires the use of a vacuum pump that most DIY guys don't have.

Adding too much refrigerant is worse than not having enough. In addition to causing poor performance, an overcharge also leaves you at risk of an over-pressure situation causing acute mechanical damage.

 

[JlewCat42]

The "cold plate" is on the low pressure side. That is where you add refrigerant.

Somewhere in the system, there is probably some sort of canister that can be removed. It is often just after the high pressure "grill". That canister is going to be the receiver/drier. Normally, if you need to add refrigerant, it is prudent to also consider replacing the drier canister. Moisture in the system will eventually become part of a chemical reaction that results in "the black death", which is a corrosive event that ruins all the major components in the whole system. The drier removes moisture from the system & suspends it in a descant. The descant has a limited capacity to hold moisture. Once it is saturated, it stops working. If the resting pressure in the system was down past about 20-40psi (depending on the system) at any time, there is a good chance that moisture got sucked in through the leak. Technically, you are supposed to draw the whole system down to perfect vacuum & hold it there for a while before recharging, to be sure that moisture is not present. That requires the use of a vacuum pump that most DIY guys don't have.

Adding too much refrigerant is worse than not having enough. In addition to causing poor performance, an overcharge also leaves you at risk of an over-pressure situation causing acute mechanical damage.

Found it .. thanks. Yes its just after the grill on the ‘T’ joint. Not sure what the pressure has dropped to in the past. It is likely that the entire system is on its last legs .. visually it looks like it might be the original (so 20 yrs +).. so I’m trying to extend as much as I can whilst other major jobs are done. Will search out drier canisters for the system too.
Appreciate your advice.