Question About Heater hose Connections

[Red57Bird]

While winterizing my 03 SANTE with the Excal 330 engine this weekend, I noticed that my heater supply and return lines are not connected in the same manner as what I have seen in other threads. One of the lines (don't know if it is the supply or the return) is connected as in the attached pic (thanks ag4ever for posting this in your heater install thread), but the other line is connected to the starboard side engine drain plug through a fitting.

First, is there a distinction at the heater core on what is a supply and what is a return? Also, I noticed that the heater didn't pump out any hot air this year. When I winterized the boat, I removed both heater hoses and, by mouth, blew air through the hose connected to the water pump. It was blocked, but after some effort I was able to blow all the water out and the hose now seems to be clear. Obviously the hose was blocked with something.

When I get the boat out in the Spring, should I route the hose currently connected to the block drain plug over to manifold, as in the attached pic. Sorry for the long-winded post. Just want to make sure I get this done right. Thanks.

[M3Fan]

RE: Question About Heater hose Connections

Looks like the return is to the circ pump. That's not too out of the ordinary and should be fine. Techinically there is a feed and return on the heater, purely from a convection standpoint I'd imagine the feed would be the top of the heater and the return would be the bottom, but it's probably not too big a deal. The core isn't some big "S" shaped bit of tubing- it's more like a big "H" with many horizontal members going between the vertical members.

[Hollywood]

RE: Question About Heater hose Connections

I'm assuming you don't have a shower. I have a feeling the factory/dealer tapped the block drain first for a hot line, in your case for the heater. If you had a shower that would have gotten the block drain first, and the heater would be fed via the intake manifold. Either is fine. The manifold would probably give you less rust/scale/sediment therefore not clogging up the heater core again. The shower will just pump that crap right out through the system, which is another reason if you had both the shower got tapped of the block instead of the heater.

[Red57Bird]

Thanks M3 - would you recommend re-routing the other hose from the block drain, and installing it over to the manifold? I'm sure that, along with hose blockage, is the reason the heater isn't working.

[Red57Bird]

Correct Hollywood - no shower, just the heater. I figured that rust scale was likely the culprit in blocking the hose. The drain on the block is such a small opening, I'm guessing that it can restrict the flow of water. I'm really leaning towards moving that line over to the manifold.

[M3Fan]

Thanks M3 - would you recommend re-routing the other hose from the block drain, and installing it over to the manifold? I'm sure that, along with hose blockage, is the reason the heater isn't working.

It's worth a try for sure. FWIW the factory install of my heater on the GT40 Ford motor has the feed coming off the manifold and the return at the block drain. Pumps heat out like ****.