QSB HX zincs broke off, acid flush HX?

[Robert Vetrano]

Twin QSBs. Freshwater flush installed and used religiously (installed Spring 2020, after the sbmar seawater protocol which I did Summer 2019)

I was changing out pencil zincs and both the HX zincs broke off, and there’s some clogging of the HX tubes at the bottom, with the built up zinc material. Can’t get to the tubes with a rod, should I just do an acid flush of the seawater circuit to clean that up? Or leave it be? Temps have been rock solid and not creeping up.

Thx.

Topic

[Rob Schepis]

Sounds good.

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Robert Vetrano

[Robert Vetrano]

Backflushed my system. Went very smoothly using my freshwater flush setup. HXs all cleaned out now, with shortened zincs in place. Note to self: check pencil zincs more frequently, lol.

Thanks for the help all.

[Rob Schepis]

Zincs ……..

Here’s a thread on zinc installing that addresses that HX zinc bottoming out.
https://www.sbmar.com/community/topic/pencil-zinc-install/#post-31085

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Robert Vetrano

[Robert Vetrano]

I also notice the zincs hit that bolt housing. Good call on trimming it.

[Scott Lambert]

I had the same issue with my QSB. Cleaned it out as best as I could and haven’t had any further problems.
I realised that the zincs were too long and hit the bolt housing in the middle of the HX. They would then bond to the bolt housing and when they were removed the brass cap would come out leaving the remaining zinc in place. Obviously whoever was changing the zincs before I owned the boat left them there to build up. Now I cut about 1/4 inch off the end of the new zinc with a hacksaw before I put it in. No more problems

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Robert Vetrano

[Robert Vetrano]

Tony, I bench serviced all seawater components summer of ‘19 per your protocols. I installed the fwf setup a few months after that service. I did pull the hx endcaps off to remove the broken zinc remnants…..that’s when I saw the zinc “residue”
or whatever it is, sitting in the bottom of the hx. I vacuumed out most of it but saw some of it blocking the lower tubes of the HX.

Just not sure if I should leave it? Or do a flush to get rid of it.

[Tony Athens]

1)—————History of “on the bench”, off engine aftercooler servicing” ?

2)————-If you are worried about the HX, what not just pull the end caps and clean out the zinc pieces you are concerned about?

Tony

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Robert Vetrano

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