Heat Exchanger cleaning for a Seakeeper Gyro

[Sdpaddler50]

My Cummins coolers go to a radiator shop for pressure testing and cleaning every 3 years, so I had always wondered how my heat exchanger for the Seakeeper Gyro heat exchanger was doing. I ended up buying a second heat exchanger that I put on, and will swap it out with the original every few years.

Overall, the tubes looked good, no blockage. I am going to cut new end cap gaskets and clean this one up.

So my question, what would you suggest to clean the internals of the raw water tube bundle?

-I was thinking of CLR?

-CLR dilution?

-How long should the solution stay inside?

Any other ideas welcome.

Photo of the new Ht Exch shown.

BTW, I realize I could have pulled the end caps and checked it, but there are other reasons why I bought a new one and they are not very $, well in boating terms that is.

[skipperpete]

Good move, that heat exchanger is mission critical in the operation of the stabilizer. You never mentioned changing the zincs, these are an “inspect regularly” item until you get a good idea of how quickly they’re sacrificing themselves. An unnoticed loss of the Zinc’s in your gyro cooling system and the subsequent failure of the heat exchanger core would be very damaging to the pumps and bearings in the gyro unit.
I haven’t worked on Seakeeper units specifically but have encountered a very similar looking type from an Australian manufacturer on large motor yachts...... ideal for keeping the water in the pool steady while at anchor apparently.

[nightowle]

My opinion is that CLR is just too weak to work in this instance.

[DougR]

To clean heat exchangers I usually source muriatic acid from a big box store, and that is normally a 20% solution of HCL. Then I dilute it with an equal amount of water , giving a 10% solution. Pour this into the salt water side of the heat exchanger and let it sit as long as it’s foaming. Flush with fresh water and check for fouling. Repeat if necessary.

[Sdpaddler50]

Doug, I got the same reply from Tony Athens a Cummins expert in CA. Will go this route. Thanks.

[wrwakefield]

Based upon this descaling article in Practical Sailor, I use CLR in case there is some aluminum in the cooling circuit.

I recirculate 50% diluted CLR - per above article- through the raw water coolant loops of the main engine and generator annually until the discharge stops foaming.

FWIW

Cheers, Bill

PS: Time elapsed between photos ~ 2 hours

[Sdpaddler50]

Thanks Bill. I already have the CLR and the build up of CAC03 is minimal so I will give it a try.