Shoalwaters
Guru
- Joined
- Feb 24, 2008
- Messages
- 681
- Location
- St. Lucia, West Indies
- Vessel Name
- "Dragon Lady"
- Vessel Make
- DeFever 41
Several recent posts have mentioned installing or revitalizing a/c systems. I have recently done both and hope the following may be of use to those about to tread the same path.
My 1984 DeFever had three self-contained Cruisairs: two originals and one new Stowaway unit installed by the PO. None of them produced more than a dribble of cold air. My a/c guy found the refrigeration side of all three units to be healthy, so the problem(s) were elsewhere.
These units have squirrel-cage fans. The fan blades are narrow strips of metal bent into a shallow "V" about their long axis. Over the years, the "V" fills up with crud so that, at first glance, the blades appear flat. Cleaning and repainting the blades produced a remarkable increase in the fans’ performance.
Even with the fans working properly, there was still precious little air coming out of the vents. The ducting was the Slinky Spring type with a glass wool insulating jacket and welded boxes at the junctions. It seemed that enough run of ducting combined with plenty of changes in direction was using up all the puff that the fans were putting out. The new Stowaway unit was located under the bathroom vanity in the aft cabin and I tackled that first. I re-located the air outlet to make the run as short as possible. 4" PVC waste pipe with two layers of insulation made a nice smooth duct. The result was better than I had hoped: lots of lovely cold air, even on the lowest fan speed. Can you spell duvet?
I had bought two new Pioneer Mariner a/c units when I bought the boat, because I didn't trust the two old Cruisairs. My success with the first unit prompted me to tackle the other two. As I was going to relocate these units, I decided to install the two new ones and put the old ones up for sale. I located the new units as close as possible to the outlets and 4" PVC was again used for the ducting. Both performed beyond my expectations. In fact the unit cooling the forward cabin worked so well that the place was like a walk-in freezer. The manufacturer told me I couldn’t slow the fan down beyond its lowest setting, so I ducted some of the air into the saloon (pic). Here are a few of the things I learned along the way:
When buying new, choose models who’s squirrel-cage fan can be rotated from horizontal through to vertical. Make sure every unit has a bug screen just in front of the evaporator.
If possible locate the units where you have good access to them. Sacrifice some storage space if necessary – you will be glad you did. Leave adequate space for the air flowing into the unit.
Install self contained a/c’s at a slight angle so that the drip tray drains easily. Route the drains directly overboard if possible. If not, then shower sump or pump sump are acceptable.
Provide a separate breaker for each unit. If something electrical goes wrong with one of them it won’t stop the others from working. Fit each unit’s power supply with a GFI receptacle next to the unit and fit the unit with a matching plug. This simplifies installation and subsequent removal. The indicator light on the GFI receptacle gives confirmation of power reaching the unit.
Install a Perko (or similar) sea strainer before the raw-water pump. Locate it where it is easy to see and below the water line so it self-fills.
Small 110v centrifugal pumps make good raw-water pumps for a/c systems. They are quiet and efficient, but they don’t self-prime. Mount below the water line and close to the strainer.
Run the raw-water pump’s power supply to a junction box next to (and above) the pump. This makes changing the pump a breeze.
My pump had a trigger switch which only ran the pump when the a/c’s wanted it. I removed this and replaced it with a conventional breaker and indicator light. One less thing to go wrong – just remember to switch the pump on or off.
Replace the hoses that feed sea water to the a/c units. Make sure there is a proper manifold so that each unit gets its fair share of water.
My 1984 DeFever had three self-contained Cruisairs: two originals and one new Stowaway unit installed by the PO. None of them produced more than a dribble of cold air. My a/c guy found the refrigeration side of all three units to be healthy, so the problem(s) were elsewhere.
These units have squirrel-cage fans. The fan blades are narrow strips of metal bent into a shallow "V" about their long axis. Over the years, the "V" fills up with crud so that, at first glance, the blades appear flat. Cleaning and repainting the blades produced a remarkable increase in the fans’ performance.
Even with the fans working properly, there was still precious little air coming out of the vents. The ducting was the Slinky Spring type with a glass wool insulating jacket and welded boxes at the junctions. It seemed that enough run of ducting combined with plenty of changes in direction was using up all the puff that the fans were putting out. The new Stowaway unit was located under the bathroom vanity in the aft cabin and I tackled that first. I re-located the air outlet to make the run as short as possible. 4" PVC waste pipe with two layers of insulation made a nice smooth duct. The result was better than I had hoped: lots of lovely cold air, even on the lowest fan speed. Can you spell duvet?
I had bought two new Pioneer Mariner a/c units when I bought the boat, because I didn't trust the two old Cruisairs. My success with the first unit prompted me to tackle the other two. As I was going to relocate these units, I decided to install the two new ones and put the old ones up for sale. I located the new units as close as possible to the outlets and 4" PVC was again used for the ducting. Both performed beyond my expectations. In fact the unit cooling the forward cabin worked so well that the place was like a walk-in freezer. The manufacturer told me I couldn’t slow the fan down beyond its lowest setting, so I ducted some of the air into the saloon (pic). Here are a few of the things I learned along the way:
When buying new, choose models who’s squirrel-cage fan can be rotated from horizontal through to vertical. Make sure every unit has a bug screen just in front of the evaporator.
If possible locate the units where you have good access to them. Sacrifice some storage space if necessary – you will be glad you did. Leave adequate space for the air flowing into the unit.
Install self contained a/c’s at a slight angle so that the drip tray drains easily. Route the drains directly overboard if possible. If not, then shower sump or pump sump are acceptable.
Provide a separate breaker for each unit. If something electrical goes wrong with one of them it won’t stop the others from working. Fit each unit’s power supply with a GFI receptacle next to the unit and fit the unit with a matching plug. This simplifies installation and subsequent removal. The indicator light on the GFI receptacle gives confirmation of power reaching the unit.
Install a Perko (or similar) sea strainer before the raw-water pump. Locate it where it is easy to see and below the water line so it self-fills.
Small 110v centrifugal pumps make good raw-water pumps for a/c systems. They are quiet and efficient, but they don’t self-prime. Mount below the water line and close to the strainer.
Run the raw-water pump’s power supply to a junction box next to (and above) the pump. This makes changing the pump a breeze.
My pump had a trigger switch which only ran the pump when the a/c’s wanted it. I removed this and replaced it with a conventional breaker and indicator light. One less thing to go wrong – just remember to switch the pump on or off.
Replace the hoses that feed sea water to the a/c units. Make sure there is a proper manifold so that each unit gets its fair share of water.