Marine Air Unit Sounds Like a Transformer…

[Traveler 45C]

Marine Air Unit Sounds Like a Transformer…

…Not Optimus Prime or the evil Decepticons, but like a power transformer.

The system is programmed to shut down the blower when the compressor shuts down.

With the system powered up and the compressor/blower off (at set point) there is a high frequency hum, like the sound of a power transformer coming from the compressor unit. I wouldn’t expect there to be any noise coming from the unit as it wasn’t doing any work but I’m not sure. There’s probably a transformer on the unit but again, I don’t know, and I wouldn’t think it should be making that much noise.

Is it normal for a Marine Air unit to sound like this? If not, what could be the problem?

 

[spcoolin]

Re: Marine Air Unit Sounds Like a Transformer…

Hmmm...No pun intended but...Typically Hatteras used Cruisair equipment, Not Marine Air.

It might help to know a bit more about what you have, What control (sounds like it must be digital if you have it set to shut off the fan with the compressor) and where the noise is coming from...I know you said compressor unit, but where...It's electrical box ? or the compressor itself ?

Steve~

 

[Traveler 45C]

Re: Marine Air Unit Sounds Like a Transformer…

Hmmm, no, its more like a buzz.

I can't tell exactly where its coming from, seems like the right side of the unit but it's hard to tell.

It's a SMX II digital control unit if I'm not mistaken.

 

[krush]

Re: Marine Air Unit Sounds Like a Transformer…

is it a heat pump or just a straight A/C unit?

Could be a transformer if it has one.

Could also be the reversing valve if it has one (heat pump). Try switching from A/C to heat or heat to A/C (whichever mode you are in) and see if the hum goes away.

 

[spcoolin]

Re: Marine Air Unit Sounds Like a Transformer…

The unit pictured is a Marine Air (likely a replacement) and should have a Marine Air "Passport" control (square in dimension) Cruisair's SMXII controls are rectangular to fit in the old manual 3 knob control cut out...

I agree that it is the reversing valve coil that is buzzing...The nut holding it on is possibly loose...
I do see the reversing valve in the picture...It's the part with 3 tubes coming out of the top (two of which are dark in color) The dark color is an indication that it has either been replaced (torch marks) or that you have some galvanic corrosion attacking that unit that will cause it to leak freon soon (if it's not already leaking) be sure it (the unit) is connected to the bonding system...
The buzz if not too loud is not really hurting anything...and yes it should go away in the cooling mode.

Steve~

 

[Traveler 45C]

Re: Marine Air Unit Sounds Like a Transformer…

Passport, couldn't remember that.

Your right about the nut. I found it lying on the chassis. I put it back on and the buzz is gone. Thanks!

I'll take a look at the corrosion issue promptly.

 

[spcoolin]

Re: Marine Air Unit Sounds Like a Transformer…

Glad it worked out Trav~

Usually if there is no bonding stud on the unit, you can just scrape off some paint on the condenser or a piece of tubing & use a hose clamp over the clean spot to clamp a piece of (end stripped) green #8 or #10 wire that you can run to the bonding system somewhere close by & tap it in.

I did see another unit next to the one in the picture (a bit of it anyway) and it wouldn't hurt to jumper all units together with green wire, and then go from the last one to the bonding system.

Steve~

 

[Brian Degulis]

Re: Marine Air Unit Sounds Like a Transformer…

I wouldn't use jumpers to bond. Each unit should have it's own green wire going down to the copper straps. The reason for that is if you jump them together and the single line going to the stips fails an internal fault in one unit could make all the units electricaly hot.

Brian

 

[spcoolin]

Re: Marine Air Unit Sounds Like a Transformer…

I wouldn't use jumpers to bond. Each unit should have it's own green wire going down to the copper straps. The reason for that is if you jump them together and the single line going to the stips fails an internal fault in one unit could make all the units electricaly hot.

Brian

I agree that individual bonding to each is best, but it's not often that I see it done that way, and they are all connected to one central bonding anyway, so that could also make one unit back feed to the others thru the bonding strap and back up the individual wires to each unit.
Not to mention that the units are tied together thru the Shore/Generator green ground buss and the same could happen thru that connection...

Yes there are also risks with bonding the units...Like if a compressor, or fan motor shorts, or leaks slightly to ground (not tripping a fuse or breaker)...The voltage will go directly into the bonding system, causing the zincs to erode rapidly and then start working on the underwater metal...

Catch 22 here I guess...Erode the solder joints in the A/C causing freon leaks one after the other by not bonding the A/C, or take the risk that a motor might leak to ground and cause damage that way...Neither option is cheap done or not done...It's the owners choice on which risk to take...

My feeling is motor leakage is not as common as solder joints in A/C systems being eaten up by not bonding them...I do see quite a bit of that, and each system has hundreds of joints to leak....Many less motors than joints to fail.

Steve~

 

[Brian Degulis]

Re: Marine Air Unit Sounds Like a Transformer…

Yes jumping is better than no bonding at all. But still there is a right and wrong way. I've never seen an OEM hat without individual wires and I've seen surveyors reject the jumper method. So for me if your going to do it anyway it's not much more effort to do it correctly.


Brian

 

[spcoolin]

Re: Marine Air Unit Sounds Like a Transformer…

Not to beat a dead horse Brian, because I think we are in agreement here...But if a surveyor failed bonding connections just because they were jumpered from one unit to the next...

It would seem that surveyor does not know much about current flow...

Like I explained in my last post...That current could & would flow just as well thru the Shore/Gen ground and make the other units live...Bonding or No Bonding.

I still agree that individual wires are best...But not because of a "making units live" risk...Only as redundancy so that if one connection fails, not all units (or more than one) loose bond to the strip...

But then again that strip "could" loose it's connection further up the line too...Then we are in the same boat with no bonding to all units & anything else that is connected after the bad connection...

"Bonding" is as the word implies...All metal Bonded Together & tied to zinc somewhere....How & where they are connected (or bonded) is subject to fail anywhere there is a connection, and thus bond is lost downstream. (or upstream depending on how you see it)

To have it even more fail safe...You could run all individual wires directly to the zinc connection but that would be more expensive, and might not look so good with a big bundle of green wires all coming together in one location.

Steve~

 

[REBrueckner]

Re: Marine Air Unit Sounds Like a Transformer…

"Yes there are also risks with bonding the units...Like if a compressor, or fan motor shorts, or leaks slightly to ground (not tripping a fuse or breaker)...The voltage will go directly into the bonding system, causing the zincs to erode rapidly and then start working on the underwater metal..."

absolutely right on!!.....this is the catch 22 dicotomy we have discussed in other threads...it's the shock protection that makes it the recommended method.
Those interested in further information can check Calder and previous threads here....

 

[Brian Degulis]

Re: Marine Air Unit Sounds Like a Transformer…

Not to beat a dead horse Brian, because I think we are in agreement here...But if a surveyor failed bonding connections just because they were jumpered from one unit to the next...

It would seem that surveyor does not know much about current flow...

Like I explained in my last post...That current could & would flow just as well thru the Shore/Gen ground and make the other units live...Bonding or No Bonding.

I still agree that individual wires are best...But not because of a "making units live" risk...Only as redundancy so that if one connection fails, not all units (or more than one) loose bond to the strip...

But then again that strip "could" loose it's connection further up the line too...Then we are in the same boat with no bonding to all units & anything else that is connected after the bad connection...

"Bonding" is as the word implies...All metal Bonded Together & tied to zinc somewhere....How & where they are connected (or bonded) is subject to fail anywhere there is a connection, and thus bond is lost downstream. (or upstream depending on how you see it)

To have it even more fail safe...You could run all individual wires directly to the zinc connection but that would be more expensive, and might not look so good with a big bundle of green wires all coming together in one location.

Steve~

The surveyor failed it because it goes against ABYC and ABS practices. If each unit has it's own bonding wire then you would have to have a failure in the copper traps to make other units hot and since that's a loop it would actualy have to break at 2 points unlikely. If you daisy chain bonding wires the failure of just one wire causes the problem. It's the same thing in home wiring for the green safty ground. The NEC does not permit daisy chaining grounds each circuit must have it's own ground for the same reasons. Keep in mind that we've learned some older Hats Don't have a green ground in the supply circuit so the bonding circuit is the the only safty ground. On those older boats it's twice as important.

It's not a big deal and daisy chaining is better than nothing. But for me the little bit of extra effort involved to get it right I'd do it.

Brian

 

[spcoolin]

Re: Marine Air Unit Sounds Like a Transformer…

The surveyor failed it because it goes against ABYC and ABS practices. If each unit has it's own bonding wire then you would have to have a failure in the copper traps to make other units hot and since that's a loop it would actualy have to break at 2 points unlikely. If you daisy chain bonding wires the failure of just one wire causes the problem. It's the same thing in home wiring for the green safty ground. The NEC does not permit daisy chaining grounds each circuit must have it's own ground for the same reasons. Keep in mind that we've learned some older Hats Don't have a green ground in the supply circuit so the bonding circuit is the the only safty ground. On those older boats it's twice as important.

It's not a big deal and daisy chaining is better than nothing. But for me the little bit of extra effort involved to get it right I'd do it.

Brian

The point I'm making is...Even with NO bonding...The units could all become "live" thru the ground since it is at a common buss. They are already tied (connected) together there (or should be) and current will flow to everything that is connected to that buss...

Bonding to zinc only protects the metal & joints of dis-similar metals (solder & copper)...And yes...It does give another path for stray current to flow, but that current would flow between units or anything connected to the ground buss...with, or without bonding.

And the older Hatts should get grounded...

Steve~

 

[Brian Degulis]

Re: Marine Air Unit Sounds Like a Transformer…

There's a big diffrence between tying them together at a single point (the ground buss) and daisy chaining. The only way one unit makes another hot is if that common buss dis conects from ground (unlikely as it's tied in at several points). Remember most Hats have Iso transformers so when on shore power your not connected to shore ground your working entirely on a sea water ground. Each unit has it's own green ground wire and is not daisy chained for the same reason your bonds should have them.Your bonding circuit does not terminate at a zinc. It terminates at a ground plate or thru the thru hull fittings that are in the system. That's a path to ground. So if you have individual bonding wires going to a common buss (ground straps) A unit thats leaking finds ground thru the system without passing thru other equiptment. Yes you could have a situation were the ground straps break in to places then everthing tied in to them between the two breaks would be hot. But that's less likely than a single wire breaking off a daisy chain ground. Again something is better than nothing but the codes do make sense for the reasons stated above.


Brian

 

[spcoolin]

Re: Marine Air Unit Sounds Like a Transformer…

There's a big diffrence between tying them together at a single point (the ground buss) and daisy chaining. The only way one unit makes another hot is if that common buss dis conects from ground (unlikely as it's tied in at several points). Remember most Hats have Iso transformers so when on shore power your not connected to shore ground your working entirely on a sea water ground. Each unit has it's own green ground wire and is not daisy chained for the same reason your bonds should have them.Your bonding circuit does not terminate at a zinc. It terminates at a ground plate or thru the thru hull fittings that are in the system. That's a path to ground. So if you have individual bonding wires going to a common buss (ground straps) A unit thats leaking finds ground thru the system without passing thru other equiptment. Yes you could have a situation were the ground straps break in to places then everthing tied in to them between the two breaks would be hot. But that's less likely than a single wire breaking off a daisy chain ground. Again something is better than nothing but the codes do make sense for the reasons stated above.


Brian

The Buss or Strap is just the common connection point...Basically a Strap is just a longer Buss, and individual wires need to be longer to get to a Buss that is further away than a centrally run strap might be.

What we are discussing here is current flow, connections & the common connection point to whatever (at least that's what I think we are discussing) and that Connections are subject to failure due to corrosion etc.

I'm not arguing against you Brian...Code...NEC, ABYC, or ABS practices...I understand the reasoning & follow them...I only suggested an easier way for Traveler to accomplish what he might want to do to protect his A/C units....It will work as we agree but yes, one connection could fail causing him to loose protection of more than one unit...My only contention here was & is that it (loss of connection) can still happen elsewhere in the system too, & suggest that neither of us know the condition, or specific routing of his particular installation.

Not all Hatt's have isolation transformers...and as you mentioned Some older Hatts don't have ground...As far as Traveler's 45C...He hasn't said either way, but I'm fairly sure his 45C does have ground at least.

Most bonding systems terminate at zinc...Usually a plate at the transom, or thru shaft brushes with shaft zincs & to rudder posts (rudders having zincs as well) or even all of the above...

As far as making other units "live"...That would first require a motor or device to leak lower current to ground than the breaker's rating that it is powered by...(yes that can happen)
A dead short would draw more current than the breaker was rated for, and thus cause the breaker to disconnect/trip that circuit...Unless as you point out, it's connection to ground is not there...
Some Hatt's even had GFI main breakers installed that would trip with a small percentage of stray current leaking.

I have mainly been speaking of odds of connection & equipment failure...And I Agree with you Brian that there is always a Right way to do things...Also that it would depend on the individual situation given the present condition of what is existing & owners budget...Often bringing things up to code is just not in the cards...
Many of the boats we speak of here were obviously not built to current code, but Hatteras has always been the best at MEP installation/layout (most times better than code) of any production builder's boats I have worked on in my 30 some years in the Marine industry....I also suggest that thru the years a boat's original installation has likey changed somewhat from the many hands that have passed over it...

Traveler 45C~

However you do it...Please bond/ground your A/C to protect against it's solder joint deterioration...

Merry Christmas Everyone,

Steve~

 

[Traveler 45C]

Re: Marine Air Unit Sounds Like a Transformer…

Traveler 45C~

However you do it...Please bond/ground your A/C to protect against it's solder joint deterioration...

That will be taken care of soon, neither are grounded or bonded.

The PO did a number on the elec system. I recently posted a thread stating that it ‘appeared’ that Hatt used the bonding ckt as the AC green wire grounding return, but have found through much snooping around that was not the case at all. I was installing a new water heater and found only the hot and neutral wires available, no grounding, so I ran my own. I later found that the PO removed the grounding wire from the heater and ran it to a female extension cord end in which he used to power the battery charger. Horrible job, butt connectors, full of corrosion and exposed wires due to heating. I’ve had this ckt shut down since having battery charger problems. I think I’ve found the cause. Had that ckt been powered it surely would have caused a fire.

So, I don’t know what other bright ideas the PO had as far as wiring the boat but I’m slowly fixing all his fixes.

 

[spcoolin]

Re: Marine Air Unit Sounds Like a Transformer…

That will be taken care of soon, neither are grounded or bonded.

The PO did a number on the elec system. I recently posted a thread stating that it ‘appeared’ that Hatt used the bonding ckt as the AC green wire grounding return, but have found through much snooping around that was not the case at all. I was installing a new water heater and found only the hot and neutral wires available, no grounding, so I ran my own. I later found that the PO removed the grounding wire from the heater and ran it to a female extension cord end in which he used to power the battery charger. Horrible job, butt connectors, full of corrosion and exposed wires due to heating. I’ve had this ckt shut down since having battery charger problems. I think I’ve found the cause. Had that ckt been powered it surely would have caused a fire.

So, I don’t know what other bright ideas the PO had as far as wiring the boat but I’m slowly fixing all his fixes.

Trav...From what you are saying it sounds like you may have a bit of a mess...

I can't and won't begin to tell you how to start or finish...I'll leave that up to others...

What I can offer is that....Your A/C systems are built/constructed with the "LEAST Noble" metals, with the most "Dissimilar Metal" joints in the boat...Therefore the A/C shows & suffers the first & most failures...

I see it Daily.

Steve~

 

[Traveler 45C]

Re: Marine Air Unit Sounds Like a Transformer…

The grounding/bonding issues are on my pri list.

BTW, can you offer any reason why I shouldn’t program the blower to shut down with the compressor? I normally leave the blowers running in the summer to keep air circulating but in the winter, air movement feels colder.

Thanks again for your help.

 

[spcoolin]

Re: Marine Air Unit Sounds Like a Transformer…

The grounding/bonding issues are on my pri list.

BTW, can you offer any reason why I shouldn’t program the blower to shut down with the compressor? I normally leave the blowers running in the summer to keep air circulating but in the winter, air movement feels colder.

Thanks again for your help.

The only reason to Not program the fans to cycle is location of the temp sensor.

If the sensors are in the return air path then they will not get an accurate sample of cabin air when the fan shuts off...The area they are located in may change temp at a differing rate than the cabin...They will need to be out in the cabin to be accurate for that use...

Thing is finding a good spot where they don't pick up radiant heat from something else such as a window glass, warm/cold bulkhead...Changing slips & having the sun on a different side etc...They are very sensitive...

You might try programming for lower slow fan speed and see if that helps, but there can be problems with head pressure in heat if you go too low.

Steve~