"Coaxing" the heat exchanger core

[Bob Bradley]

Well, at 10:30 last night, I finally finished flushing the Cascade out of the F/W side, and removing the side plates from my heat exchanger. I believe it was Genesis in an earlier thread who told me that I had to "coax" the core out. Well, the core is in there pretty solid. I let it be, as I was fairly shot by this point, but I do need to get back in there and finish the job.

Any tips on the "coaxing" process. The only thing that comes to mind for me is tapping a block of wood against the opposite end of the core. Is there a better way? It simply would not budge or wiggle.

[Genesis]

Both flanges are off?

You can CAREFULLY use a chisel between the flange and the tank on the INLET side to break the seal on the gasket.

Be careful with hammering on the other end - if you deform that big outlet tube the gland will not seal and then you're screwed.

[Bob Bradley]

Both flanges are off. I had presumed that it had to come out from the gland (outlet) end of the H/E. Is that correct? Can it come out either end?

[MikeP]

The HE will ONLY come out from the input side, where the HE flange is located.

After it's out, be sure you check the flange for warpage and true it as necessary. Otherwise you risk leaks.

[Genesis]

Both flanges are off. I had presumed that it had to come out from the gland (outlet) end of the H/E. Is that correct? Can it come out either end?

No, it has to come out from the INLET side. There's a flange there that is holding it in place.

You're trying to push it the wrong way.

[Bob Bradley]

I thought that the "flange" was the outside cover, the one held in place by the 1/4" bolts. Is there a seperate flange beside this? (It was rather late when I finally got that far last night.)

[Genesis]

Two flanges, one on each side.

You have one on the input side (where raw water goes in) and one on the outlet side. The outlet side has O-ring seals in the gland (there's a cast iron plate that goes on, then the exit flange.

The inlet side just has a flange which accepts the inlet hose.

Once you remove those plates (THREE pieces) the core itself is visible.

The outlet side just has a big round tube that fits into the gland. The INLET side is constructed with a flange which is up against the tank. There is a gasket on both sides of that flange - one between the core's flange and the tank, and a second between the core's flange and the mating inlet flange.

You push the core out from the OUTLET side towards the INLET side.

[Will]

I missed the types of engines you have. However, my J&T 6-71TIBs have identical heat exchangers. The heat exchangers do not mirror each other. Therefore, the input side of the heat exchanger for the port engine is the side with the "O" ring. The HE zinc is on the output side. On the Stbd engine, the "O" ring is on the output side and the HE zinc is on the input side. In both cases, the core is removed from the side with the zinc.
Will

[SereneWarrior]

I just did this job over the weekend and experienced the same issue with convincing the core to come out. I used a small wood block resting against the outlet side that I lightly tapped with a hammer. I was very consciousl of not wanting to deform the soft metal. Anyway, it was enough to break the core loose from the housing and then I could pull it out the inlet side. After that the job was routine.

[Bob Bradley]

Two flanges, one on each side.

You have one on the input side (where raw water goes in) and one on the outlet side. The outlet side has O-ring seals in the gland (there's a cast iron plate that goes on, then the exit flange.

The inlet side just has a flange which accepts the inlet hose.

Once you remove those plates (THREE pieces) the core itself is visible.

The outlet side just has a big round tube that fits into the gland. The INLET side is constructed with a flange which is up against the tank. There is a gasket on both sides of that flange - one between the core's flange and the tank, and a second between the core's flange and the mating inlet flange.

You push the core out from the OUTLET side towards the INLET side.

So there are FOUR gaskets per heat exchanger? Well that's great. I took an hour round trip last week to Atlantic DD to pick up the parts I needed, and they only gave me three gaskets per exchanger.