Mystery water cooling pipes

[sealives]

I am sure this question has a very simple answer, but due to the construction and hidden nature of 2 water cooling pipes, I cannot figure where and what they do. So, the engine is a Westerbeke diesel M25XPBC. It is a fresh water/raw water system with a water heater option. I am quite familiar with engines, but I appear to have a mystery couple of pipes!

The attached picture shows 2 pipes going off into the rear of the picture. They are not the pipes to the water heater, I know where they are. One pipe at the engine end comes off the bottom left corner of heat exchanger. The other pipe at the engine end connects to the exhaust. I have tried to trace them but they simply disappear behind mouldings which cannot be removed. I suspect one pipe goes to a skin fitting above the water line, but I could be wrong.

As one end connects to the exhaust, then I think that is raw water being pumped into the exhaust on its way out to the sea. So what is happening where I cannot see?

The 2 pipes in the foreground are the flow/return to the heater.

The reason for needing to know, apart from curiosity, is I need to replace lots of cooling pipes and I have to understand where these go and if they are critical.

 

[barnstormer]

They go back to your heat exchanger that is built into your water heater.They allow you to heat water from the heat of the engine when you are away from the dock.

 

[sealives]

Thanks barnstormer, but as I said in the post, I have identified the pipes that go the heat exchanger - shown in the foreground of the picture, so that is not the answer. I have also identified the raw water intake as well.

 

[Stu Jackson]

Here are the manuals: http://www.c34.org/wiki/index.php?title=Manuals

The basic flow diagrams are in the manual.

Follow the pipes/hoses. I know you say they're hard to follow, but you have the raw water intake to the pump on the starboard front of the engine, pump to HX, HX out to the exhaust riser. Any other hoses are for the freshwater coolant between the engine and the HX.

Good luck.

 

[Claude L.-Auger]

.... One pipe at the engine end comes off the bottom left corner of heat exchanger. The other pipe at the engine end connects to the exhaust. I have tried to trace them but they simply disappear behind mouldings which cannot be removed. I suspect one pipe goes to a skin fitting above the water line, but I could be wrong.

As one end connects to the exhaust, then I think that is raw water being pumped into the exhaust on its way out to the sea. So what is happening where I cannot see?

As Stu says you have to follow them. I suspect that you are right, i.e. the hoses go to an anti-siphon valve loop above the water line to prevent raw water from being siphoned back into the engine when there is no exhaust pressure. One type frequently seen looks like the attached.

http://www.westerbeke.com/Accessories/antisyphon_valve_loop.jpgThe hose coming from the HX would be connected to one end, and the other going to the elbow connected to the other end. Good luck.

 

[Chris Patterson]

I'm pretty sure Mr. Auger is correct on this. Mine is that way.

 

[sealives]

I'm pretty sure Mr. Auger is correct on this. Mine is that way.

Gentleman, thank you very much. I am confident this answers the question, and now makes perfect sense. I will go in search of this valve, but to renew the pipes, I am going to have to start removing bulkheads and 'heads' - ho hum, another weekend passes.

 

[reworb]

I used to have a 1998 28 MKII. On mine at least, the siphon break (valve) was inside of of the port cockpit locker at the hull side. I had to almost climb inside the locker to get to it. the

 

[sealives]

I used to have a 1998 28 MKII. On mine at least, the siphon break (valve) was inside of of the port cockpit locker at the hull side. I had to almost climb inside the locker to get to it. the

Thanks very much - I will certainly start there. Upside down in the port locker - looking forward to it!

 

[reworb]

To clarify that's the large locker not the small opening seat at the stern .

 

[woodster]

Do you have any idea of who makes the valve pictured and if it was suitable for engine water (hot) with that plastic piece? I'm sick to death of the twice monthly maintenance my Groco valves take.

try here http://www.scotpumpmarine.com/sn/SN-890-913.pdf

they work fine for engine water they are all over the place

 

[sealives]

To clarify that's the large locker not the small opening seat at the stern .

Slipped down to the boat and yep, found the anti syphon valves in the locker (well hidden behind fenders!).

Thanks to all who helped.