Woodenboats, Feedback on Isotherm’s through
hull condenser seems to be that if is installed in
cockpit drain regular
cleaning is easy with a long bottle brush. Boater on
great lakes reported he is planning on replacing his
Isotherm through
hull condenser because keeping it clean in the lakes cold water is a problem. I wonder if boaters with these through hull units are aware of the zinc just inside the hull needs frequent
inspection. If this through hull condenser is not operated in tropical waters compressor
oil overheating failures are less likely. If operated in tropical conditions fan cooling of compressor may be required.
Cheechako, Same answers from boaters in tropical waters, disconnected Adler Barbour water pumps.
Vasco, In 2004 after receiving three water cooled EZ Kold condensing units with failed pin hole in cupronickel water tube I discussed problem with EZ Kold. I also informed many owners of water cooled E Z Kold machines as I could. Best
advice I could give was to drain water from condenser and remove
pump and hoses running system on air cooled condenser only. Once seawater is mixed with refrigerant complete system is junk. Ten years later after more condenser failures E Z Kold just before the shut down recommended pumping water from fresh tank through condenser. Although it was a little late PVC homemade water cooled condenser were fabricated and installed on units returned to factory for
repair.. The air cooled portion of E Z Kold machines could still be operated indefinitely if water cooled portion was deactivated before water mixed with refrigerant..
Rich, You are correct refrigerant control cap tube versus valves and many other design variations that compromise or improve dependability of
marine refrigeration need to be discussed. Your Cool Blue unit is simple, most energy efficient and is basic reliable refrigeration in the right application. If I get the time I will put together a variation of best design concepts for all application of
icebox conversion refrigeration for cruising
boats. Manufacturers today in all mechanical industries are over complicating their designs hopefully to achieve better results without considering after market
maintenance do it yourself support. The old response of sending it back to our shop and we will
repair it is a stupid answer for conversion refrigerators. Another manufacturer’s response is call a local repairman. We have all seen evidence on the web that when phoning manufacture doesn’t help solve refrigeration problems. The secret to a successful ice box conversion design is energy efficiency,
reliability, with
parts and
service available in most
ports around the world.
Rich and John, I am sorry but there are good reasons why capillary tube tubes are excellent refrigerant flow control devices and there are other reasons why and when Thermo Expansion Valves offer advantages. Correct refrigerant flow is important to keep liquid refrigerant phase change (superheat) to vapor while inside evaporator. Compressor manufactures set maximum and minimum refrigerant flow limits for each compressor design. Example small Danfoss BD compressor designs limits are difficult to stay within if standard TEV valves Btu limits are excessive. The main reason engineers prefer cap tubes over TXV and their refrigerant receiver
tanks is to insure compressor’s long life with more accrete refrigerant flow control. Thirty years ago I worked with an
engineer at Parker valves for six months to develop a reduction to standard wide open orifice expansion valves. Final solution was adding a fixed orifice before TXV on large holding plate systems. I used this orifice reduction method on mutable hybrid large five gallon holding plates and a
single BD2.5 compressors back then. It is true that large holding plates systems and poorly designed standard evaporator systems are more efficient with TXV refrigerant flow control.
John, Your suggestion, ["With a TXV system you don't need a
keel cooler or any other type of water cooling . You can't really just add the TXV to cap tube system they are completely different designs. You could use your compressor and controller if they are in good shape and build a system around them ."] Is a very unusually strange opinion..
Yes, Technautics use of expansion valve with large eutectic plates and aBD35 compressor running at low speed this might be the most energy efficient system available today. Cost of replacing correctly sized cap tube with a TXV and refrigerant receiver will far exceed the risks and benefit.
Jon, have you had to replace the Isotherm SP’s zinc if so how long do they last? Another question are all your boat's through hulls grounded?
My intent in this thread was to get boaters more involved in mobile
boat refrigeration a dying industry. The eighteen True and False question based on a boater experience could be answer either way maybe True or maybe False. I also wanted to hear from technicians who are attempting to support varies small confusing over designed boat refrigeration systems and problems boat owners experienced.