Anode rod and Engine AC

[Secarider]

Today I checked the condition of the Anode rod and was surprised to see the bottom 2 inches of the rod nearest the install nut was down to the metal internal rod, the rest of the rod was worn but not to bad. The motorhome is less then a year old. Never put anything in tank beside well water. I guess something in well water is eating up rod quickly. No issue with my pavilion WH eating up rods in 4 years in this house.

Also took MH to dealer to check engine AC servicing. While driving home from NJ a couple weeks back temp 84 outside, the longer I drove the warmer the temp got coming out of AC vents. Even tried recirculate. Well they came back and said outside temp 83, MH inside temp was 84, output temp was 54. He also stated pressure was good. So much for thinking the Freon was low.

[Iwritecode]

Originally Posted by Secarider

Today I checked the condition of the Anode rod and was surprised to see the bottom 2 inches of the rod nearest the install nut was down to the metal internal rod, the rest of the rod was worn but not to bad. The motorhome is less then a year old. Never put anything in tank beside well water. I guess something in well water is eating up rod quickly. No issue with my pavilion WH eating up rods in 4 years in this house.

That's pretty normal. For some reason that part is always the first to go. You probably have quite a bit more use left in it.

[5picker]

I agree, not uncommon and not a reason to replace it yet.

My thoughts are... that part of the rod goes first because it is the nearest to the threaded plug portion and the bung and they are the closest metal for the electrochemical process to happen.

[MtBiker]

Mine was fine a year ago and was completely used up by this spring. Ordered up on line a couple of new ones, delivered for less than one at the local RV store.
Funny I called my brother and my buddy to ask them how often they changed the anode in their trailers. Both of them said "Huh" "Wow never thought of it."

[jimmoore13]

The anode is a "sacrificial" anode. It is designed to disintegrate INSTEAD of other things corroding. Many outboard and stern-drive boat motors also rely on sacrificial anodes to protect the (typically) aluminum housing of the drive submerged in water...salt or fresh.

Your home water heater also has a sacrificial anode that should be checked and replaced occasionally. At roughly $10 for a new anode, it's doing its job, and you can use the old one until it's pretty well all gone, then replace it.

As for the AC performance, if they tested the unit and it was delivering 54 degrees at the dash vents, it sounds as if it was performing well. You don't mention the relative humidity, but in humid conditions AC units can "freeze up." The condenser behind the grill can actually ice over because there is so much moisture in the air that is attempting to cause the "phase change" in the "freon" that the relatively cool condenser causes moisture in the ambient air to condense on the outside surface, and that moisture slowly creates a layer of ice on the condenser. Once that happens, the freon cannot change phases (liquid to gas or the reverse) and the AC stops making cold air. If this happens again, stop and check for ice on the condenser.

More on this: Car Air Conditioning Troubleshooting | DoItYourself.com

[polishapple]

Originally Posted by Secarider

Today I checked the condition of the Anode rod and was surprised to see the bottom 2 inches of the rod nearest the install nut was down to the metal internal rod, the rest of the rod was worn but not to bad. The motorhome is less then a year old. Never put anything in tank beside well water. I guess something in well water is eating up rod quickly. No issue with my pavilion WH eating up rods in 4 years in this house.

Also took MH to dealer to check engine AC servicing. While driving home from NJ a couple weeks back temp 84 outside, the longer I drove the warmer the temp got coming out of AC vents. Even tried recirculate. Well they came back and said outside temp 83, MH inside temp was 84, output temp was 54. He also stated pressure was good. So much for thinking the Freon was low.

I found by flushing every time i came back from a trip and flushing the hot water tank the rod was perfect. little our no eating away.

[jimmoore13]

When I mentioned AC Freeze-Up, I incorrectly suggested the freezing happens at the condenser in front of the radiator. The freeze-up happens on the "heat exchanger" (evaporator) inside the HVAC unit in (or near) the cab. The heat exchanger is chilled by refrigerant, and the warm, moist cabin air passes through the AC heat exchanger, and moisture in the air condenses on the surface of the heat exchanger as the air is cooled. That enables the AC to dry the air. That's why a typical air conditioner in a home has a drip pan and condensate drain.

If the amount of moisture is too much for the system, the condensation will form a layer of ice that eventually prevents air from flowing through the heat exchanger. I can't say for sure, but I believe fan-forced air is able to bypass the heat exchanger, maintaining air flow, but the air is no longer chilled. The only solution is time to allow the ice to thaw...or, depending on the design of the system, add heat from the heater to melt the ice. (This depends on whether the heater core is before or after the AC heat exchanger.)

Since you are attempting to cool the cabin area of a motor home, it's possible that you may experience a situation similar to a regular house. Like a house, there is a LOT of warm, moist air in a motor home. In the cab of a pickup or cabin of a car, there is far more limited air volume to chill and dry. If set on "recirculate", once cooled and dried, the AC doesn't struggle dealing with moisture. But, if your driving cab in the MH isn't isolated from the living quarters, the volume of air to be chilled and dried is comparatively enormous. And if the "vehicle" AC system in the MH isn't scaled to cope with this, it could be overwhelmed pretty easily.

Again, I'm assuming that you may be dealing with hot AND humid conditions...not typical hot, dry conditions found in the SouthWest. If so, as you prep for departure, with doors and storage areas wide open to the outside air, your MH may intake a huge amount of hot, humid air, and the vehicle AC may simply not be up to the task of cooling and drying it all before inevitable freeze-up.

If any of this makes any sense, perhaps you might prep the camper in advance, then close up, connect to shore power, and run the roof-top AC unit(s) full blast for a while to get a head start on cooling and, especially, drying the air before you take off on the road. And, while driving, try to avoid introducing outside air into the cabin at pit stops, etc. Keep the doors and windows shut, and plan your entry and exits to minimize "pumping" outside air into the cabin when opening and closing doors. Each time you open a door, it sucks a huge amount of cooled, dried air out the bottom of the door opening (cold air sinks) and replaces it with warm, moist air at the top. And when you close the door, it happens again.

All this yammering may not describe the source of your problems. It's just a hunch. This video shows how the AC system works, and when you look at the image of the evaporator (heat exhanger that cools the cabin), you'll see how easy it can be to have it freeze up with a coating of ice under the right circumstances.

https://www.youtube.com/watch?v=zalg5VyPvjk

[jimmoore13]

P.S. In humid conditions, go to recirculate immediately. If you are cooling outside air, it's impossible to make it dryer. But if you go to recirc immediately, you also immediately begin drying the inside air, and even in a big MH, there's just so much air in there. As it passes over the evaporator (heat exchanger), it starts drying the air immediately, and as the air dries more and more, the chance of freeze-up is minimized.