Finding and changing anode on HX?

Rortega46 · November 28, 2015, 07:53:59 AM

Please help me find and change the sacraficial zinc anode on the heat exchanger. From prior posts on this site, I understand it's difficult to get to but I can't even find it. I've searched from every access point and felt around the underside of the HX and still can't find it. If and when I find it how do I change it? Type of tool, size, steps, tips and best access point? I know the 2nd time changing wil be easier than finding it. Thanks in advance for your help.

Stu Jackson · November 28, 2015, 09:19:23 AM

Randy, this link has a lot of HX pictures:

http://c34.org/bbs/index.php/topic,6920.msg46266.html#msg46266

It's usually on the back (aft) end, facing down from the horizontal. If it's a 3 inch HX, the head of the nut takes an 11/16" wrench or socket.

tonywright · November 29, 2015, 07:46:49 AM

You will find it easier to access the heat exchanger if you first remove the box around the back of the engine in the aft cabin (there are tips elsewhere in how to do this: involves removal of six screws). The anode is on the lower part of the HX, but faces slightly forward as I recall.

Tony

Ron Hill · November 29, 2015, 11:20:30 AM

Randy : Just feel along the bottom the HX.

It is usually near the starboard end of the 3" HX on a M35BC engine!!

Stu Jackson · November 29, 2015, 01:18:14 PM

Mine's on the port side.

Golly, folks, open up the aft cabin hole and simply look. If you don't wanna get down there, then try a mirror from the top. I've been servicing our HXs for 17 years without taking the "furniture" out of the aft cabin, but that's a good idea, too.

Good luck.

tonywright · November 29, 2015, 07:04:34 PM

Stu

Maybe the larger engine and slightly larger HX fill up the available space a little more on the Mark II? Just a possibility: I have not seen a MK I to compare. There is certainly very little space to work on mine without removing the furniture. But then I do like to see what I am doing!

Tony

Stu Jackson · November 29, 2015, 07:06:35 PM

Tony, I was down in the back of a friend's Mark II and space below the aft cabin on his boat is palatial compared to my Mark I.

It's a ballroom down there.

tonywright · November 30, 2015, 07:34:59 AM

Then I stand corrected.

Tony

Stu Jackson · November 30, 2015, 10:44:00 AM

Tony, what I found on his boat, as on yours, is that the wider cockpit makes the space down below the aft cabin really different. That and the fact that the muffler is moved aft on the Mark IIs whereas it is under the head sink on the Mark Is. Lotsa little differences all add up.

Rortega46 · December 01, 2015, 06:50:06 PM

Thanks everyone for your comments and suggestions. I'll take another look when I get to the boat this weekend. It will be something to do when it's too cold to go for a sail.

Rortega46 · December 27, 2015, 08:20:45 AM

Ok everyone, two more trips to the boat to search for the zinc anode without success. I have a new theory and would appreciate feedback. The M35B parts manual shows both a zinc anode and petcock in the same location on the HX. My theory is that there is one or the other, but not both. Does anyone know if there is either a petcock or a zinc anode? Anyone have both? Should I remove the petcock and put an anode in its place?

It's 78 degrees today and I'm going for a sail. It's a great day down south.

Jon W · December 27, 2015, 03:48:39 PM

A dock neighbor of mine is a new owner of a Tartan 3700. He was going to replace his HX zinc. He couldn't find one either. His mechanic told him he has a SST HX so doesn't need a zinc in the system. Any chance you have a SST HX?

Jon W.

KWKloeber · December 28, 2015, 12:43:30 PM

Quote from: Rortega46 on December 27, 2015, 08:20:45 AM
Ok everyone, two more trips to the boat to search for the zinc anode without success. I have a new theory and would appreciate feedback. The M35B parts manual shows both a zinc anode and petcock in the same location on the HX. My theory is that there is one or the other, but not both. Does anyone know if there is either a petcock or a zinc anode? Anyone have both? Should I remove the petcock and put an anode in its place?

It's 78 degrees today and I'm going for a sail. It's a great day down south.

Pics!!

kk

Ken Juul · December 29, 2015, 05:16:14 PM

http://www.c34.org/wiki/index.php?title=3%22_heat_exchanger_mounts

In the first picture the zinc screws into the fitting in the lower left of the HX

Rortega46 · December 30, 2015, 06:21:54 AM

Ken: I'll take another look when I get a chance this weekend. Attached is the diagram from the M35B parts list. Are #s 17 & 18 both there or is it one or the other? Westerbeke is closed this week and I hope to call them next week to get their thoughts.