Running wires for a/c control

SoulGravy

I’m currently replacing the stock a/c unit that came with our 342 with the marinaire unit that several others here have recommended. I’ve got the old unit out and am trying to figure out how to get the wires for the control panel and remote sensor run up to the place where the control panel is mounted. This seems like the hardest part of the whole deal. Any advice from others that have done this before?

Handymans342

Yes, easy. Go under the storage tub and work your way into the cabinet

Dude_Himself

What if I told you you didn't need to replace the wire?

The factory units came wired with Cat5e with an 8P8C (commonly mistaken to be an RJ-45, but you can typically use those two connector names interchangable - no worry). The wire was terminated as a crossover cable. The cable that came with my new unit was also a Cat5e, but wired as a standard patch cable.

So, reusing the old cable is likely as simple as reterminating one end.

SoulGravy

Dude_Himself said:

What if I told you you didn't need to replace the wire?

The factory units came wired with Cat5e with an 8P8C (commonly mistaken to be an RJ-45, but you can typically use those two connector names interchangable - no worry). The wire was terminated as a crossover cable. The cable that came with my new unit was also a Cat5e, but wired as a standard patch cable.

So, reusing the old cable is likely as simple as reterminating one end.

This would make my day.  Researching now to see how to do this.

Dude_Himself

Where in Georgia are you?

SoulGravy

Cumming

Handymans342

Is that where they make Cummins diesels??

Black_Diamond

Really easy to run a new wire. As noted above, remove the sbd storage tub. Pull the new wire with the old behind the vinyl wall covering. 

The new unit is SO much quieter. You will appreciate it!  

SoulGravy

Handymans342 said:

Is that where they make Cummins diesels??

Only thing they make here is traffic.

Michael T

Also if lucky and the present cable was not anchored between the control panel and the underside of the front berth then you can attach the new cable to it and use the old cable as a "fish line" to pull it through. I have done this with boat wiring before.

SoulGravy

Michael T said:

Also if lucky and the present cable was not anchored between the control panel and the underside of the front berth then you can attach the new cable to it and use the old cable as a "fish line" to pull it through. I have done this with boat wiring before.

Unfortunately, the existing wire is in a wire loom taped together with a bunch of other wires, so this isn't an option.  It's what I was planning on doing.  However, thanks to the Dude, I figured out I didn't need to run a new control cable.  I do, however, have to run a sensor wire because this unit's sensor isn't built into the control panel.  I'm still trying to figure out where I'm going to mount that.  I'll get back to it Thursday and hopefully wrap it up then.

raybo3

If I am not mistaken the sensor mounts at the return air duct and on my boat its right at the unit.... Very easy......

Handymans342

Your remote sensor is your thermostat

Handymans342

You don't need the other sensor. Just run the new cable and install the new thermostat

raybo3

Handymans342 said:

Your remote sensor is your thermostat

You can use both. I have a remote sensor but it is not needed.....

Black_Diamond

It was real easy to run a new t-stat wire on my 342.  

SoulGravy

Handymans342 said:

Your remote sensor is your thermostat

Not according to Marinaire.  I just reached out to them again to confirm.  The unit has a sensor on the unit itself and a remote sensor that can be mounted separate from the thermostat, but the thermostat itself does not have a sensor on it. 

If that's the case, I do need to run the remote sensor or the unit will always run based on the readings in the locker.

I wonder if they've updated the design since others here have installed.

Handymans342

Wrong. The thermostat cycles the unit based on the room temp which could be the sensor mounted on the unit

Handymans342

Mine works great as is and is nice and quiet

raybo3

That is exactly correct. It has to do with the deadband. That why the sensor is located at the return air duct. However the unit will still run without the remote sensor...

SoulGravy

Handymans342 said:

Wrong. The thermostat cycles the unit based on the room temp which could be the sensor mounted on the unit

That's what I mean.  It'll run based on the sensor mounted on the unit, but the unit will be in the locker.  I'm going to run the remote sensor so that it runs based on the readings in the cabin.

Handymans342

Well the sensor is located in the return air stream which is the air in the cabin

SoulGravy

Handymans342 said:

Well the sensor is located in the return air stream which is the air in the cabin

Got it.  That makes sense.

Dude_Himself

I'm guessing no one caught the MarinAire brand vs. Marine Air?

I have the MarinAire unit, which has two thermometers: one by the inlet and one at the remote panel (not the remote control). It'll run until both those thermometers are satisfied, not just the return air one.

SoulGravy

Thanks for the answers, comments, etc.  I buttoned this up last night!