Surface Temperature of Marine Air Compressor Units

[BroadCove]

I'm in the final stages of taking possession of a 2005 Grand Banks Eastbay 47. The sale has closed, but there is an escrow account to address any mechanical items that arise on sea trial (New England boat, sale completed over the winter, boat going in the water this week).

On the initial out of water survey, our surveyor noted that one of the three Marine Air compressor units had browned (visually). Two of the three units had been replaced within the past few years. A technician at the boatyard evaluated the three units today and found the following (with commentary):

"Two new AC units surface temps 62F and 68F, the old unit is 95F. There is no documented specification I am aware of for compressor case temperature. The older unit will likely have a different gas (R22 vs newer R410) that will operate at a different temperature. This browning is very common; the unit is functioning perfectly at this time."

With two of the three units having been replaced already, it's only a matter of time I expect before I'll need to replace this third unit. I'm guessing this is a long shot, but if anyone has experience or documentation of the normal operating temp of the compressor, or whether browning is "normal", I'd welcome your feedback!

 

[Redhook98]

Or that unit could last another 15 years. All three of my units are 30+ years old. No issues at all. Blow ice cold when needed and hot when needed. Keep up the maintenance and they should be fine. Never heard of a unit "browned" though. I would not be so quick to replace a good working system unless you just want to throw money at it.



For the record, mine all get pretty warm when operating. Either the compressor or the cooling lines. Depends on the cycle it's on.

 

[Comodave]

IMO if the unit is working now that is all you can ask. To take money from the escrow account just in case it stops working at some point in the future is not ethical. You are buying a used boat and all that is expected is that the things are working at the time of the survey and sea trial. No telling if they will stop working tomorrow or 10 years from now. Just enjoy your new boat and give us some photos of it.

 

[tiltrider1]

I have replaced all three of my heat pumps after 30 years. Two had electrical control box failures and the third had a compressor failure. The compressor gave no sign of problems until one day it started to make horrible noises which lasted 5 days before total failure. The 5 days was enough warning, I ordered its replacement on day 2 and swapped units on day 6.

 

[BroadCove]

Thanks, all. Not looking to replace a working unit, or to try to argue for money out of escrow on a working unit. Was really just wondering if the explanation for the difference made sense..(If the surveyor hadn't documented this, it wouldn't have been in my radar at all.) Appreciate the input, and putting this one to bed.

 

[BroadCove]

Thought I would follow up with "the end of the story" for any interested. On the day of sea trial - the day after my original post where the tech at the seller's location reported the a/c unit in question working "perfectly" - the a/c unit was not functioning. The control panel worked, but no blower/fan or heat. After about 10 breaker resets, we finally were able to get the fan to work, only to be quickly followed by the LPF code (low refrigerant).

Further inspection following the sea trial by a qualified marine air technician showed a long time refrigerant leak and compressor failure as a result. That technician said that the much higher operating temperature was a clue, and that the color change in the paint on the unity is evidence of being run at higher temperature for long periods of time due to low refrigerant (paint was "baked").

So the unit is being replaced, which is made more expensive by the change in refrigerant since this unit was installed, resulting in additional parts/steps in the replacement. All covered by the escrow, as this item was flagged first by my surveyor out of the water, and then of course confirmed when the unit did not function on sea trial.

Just wanted to close the loop here on this!

 

[DavidM]

It takes a very high temperature to turn white paint brown. Cummins engines are white and if the engine has been run hard for an extended period, the air coming out of the turbo will turn the paint brown. But that takes 500 or so degrees.

I suspect your A/C compressor is brown due to external environmental causes, not internal heat. Any A/C compressor that got hot enough to turn the paint brown would soon be toast.

David

 

[BroadCove]

Thanks, David. The paint color was more of a "cream" or "yellow" than actual brown. I'm no expert on these things, but it wasn't functioning, and it was running 50% hotter than the other units when it had been running due to a refrigerant leak. One way or another, it now *is* toast.

 

[danderer]

It takes a very high temperature to turn white paint brown. Cummins engines are white and if the engine has been run hard for an extended period, the air coming out of the turbo will turn the paint brown. But that takes 500 or so degrees.

I suspect your A/C compressor is brown due to external environmental causes, not internal heat. Any A/C compressor that got hot enough to turn the paint brown would soon be toast.

David

Actually I was also told about (and shown examples of) the heat-induced-paint-color-change by a well-respected marine AC tech.

I guess Cummins uses a better-quality paint.