Recharging CruiseAir AC

My reverse cycle AC rig is a pretty old (I am guessing original to the boat from 1986) and I think it could use a coolant recharge. We've been running the "heat" over the winter and it pretty much sucks-ass. Upon closer inspection last week, I noticed a "tank" (not sure if expansion or not) about 2"x4" oval with frost all over it. From my limited experience with HVAC, I think I recall this as a sign of low refrigerant.

I have been meaning to learn more about HVAC and this is as good a time as any. I have downloaded and printed the manual for the unit (at least I think so) and want to buy AC pressure gauges to add to the tool "collection".

I'd be most appreciative for any helpful tips you all could give on the process. TBH, and I can't believe I am going to say this, a new Webasco unit is only $1700 for 16k BTU, and with just two hoses and a few electrical connections to replace (and a strong back), if I should screw this one up, replacement would be the worst tragedy.

Thanks y'all,
Tom-

A buddy charged mine last year for a few beer credits without a manual, I know mine is from the 80s as well. There is a wiring schematic under the cover and the pressures are stamped on top. I know it is hard to read but here is what my 16,000 115 volt unit reads.

Refrig R22
Test Low side -150 PSI
High Side PSI 300 PSI
Charge 1#-7oz

NICE! Thanks!!! I will take a peek.

A pro will have the tools and knowledge to tell if you need a recharge and if you have one or more leaks.

rwidman said:

A pro will have the tools and knowledge to tell if you need a recharge and if you have one or more leaks.

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Where is the fun in that? That means I don't learn anything.

Tom.B said:

Where is the fun in that? That means I don't learn anything.

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You could take a class. Physically doing the work is not usually hard but knowing exactly what to do is the problem. When I worked in a large public school maintenance division, HVAC mechanics were the highest paid trade.

Replacing your existing unit is a DIY job for a moderately skilled DIY person.

Tom: I took my A/C classes from the Army Corps of Engineers over at Ft. Meade, MD. as a civilian. The classes were attached to Anne Arundel Community College, and I understand still is. Most of the course is really about electric, but was good enough to help me do my own A/C repair and maintenance. Check out your local Community College.

I'm looking at moving the unit I have now from a closet to the genset space below the galley, and installing another one for pilothouse only. The integrated A/C units are pretty simple to work with, but with the laws about gas releases and such, I think it's better to have a local tech do the vac and charge.

Tom, there is a young guy in New Bern who used to be a lead tech at Jarrett Bay and did a lot of AC work for me while there. He is trying to set up shop as an independent and just got done doing a bunch of work on my boat (non-AC this time, mostly helping on an exhaust system project and some electrical). He has got the equipment and can get the gas and is also great at electrical and plumbing. He could teach you the basics and you guys could do the project together. The price is very right. The bad news is he is off to crew a boat in the Bahamas for a month. PM me if you want contact info.

make sure that your return air filter and evaporator coil is clean. Anything that reduces the airflow across the evaporator coil can cause frosting (in cooling mode). You can also use an amp probe and check the amperage the unit is pulling. Check against the units FLA amperage. This can only serve as a guide as the current will vary with loading. I would look for amperage around 2/3 of FLA. If you acquire a gauge you can place it on the suction side of the compressor (the larger of the two lines). For r-22 you should see suction pressures from about 60 to 80 psi depending on load. Lower readings than that could be due to low refrigerant or restricted airflow across the evaporator. I guess in reverse cycle you could have low water flow which would cause frosting too. Visually check for leaks by looking for oil as it usually comes out with the refrigerant and collects dirt.