Remote Pressure Tank and Expansion Tanks.

jviss

.
Feb 5, 2004
4,627
Tartan 3800 Westport, MA
This is interesting. I have a Westerbeke with a remote coolant pressure tank because the water heater is higher-up than the engine. The Westerbeke part naming and explanations are a bit misleading, and not entirely correct, in my opinion; but I'm open to learning. They call it an expansion tank. I always thought "expansion tank" was synonymous with "coolant recovery tank." Maybe I'm wrong about that. But anyway, I have one, part number 24177, "Metal tank used when the hot water tank (heated by coolant water) is located at or above the top of the engine. **When adding a tank to the cooling system change out the cap with that on the manifold."
I have coolant recovery tanks at both locations, at the exhaust manifold tank near the engine, and also at the remote tank. I found this in the engine manual:

"NOTE: When the remote expansion tank #24177 is used, the plastic coolant recovery tank
should be removed and discarded and its connection point on the exhaust manifold plugged
with a 1/8 NPT fitting."

So, should I do that, eliminate the coolant recovery tank near the engine?

Note that the pressure cap on the remote tank is rated at a lower pressure than that on the exhaust manifold, per Hansen Marine Engineering, and the manual, which has the note by the remote expansion tank "Pressure cap is rated lower than manifold cap."
 

dmax

.
Jul 29, 2018
493
O'Day 35 Buzzards Bay
I have a remote coolant tank as well - there is no recovery tank attached to the manifold (the outlet is sealed). My boat came that way so I don't know if it's original or not but it seems to make sense.
 

jviss

.
Feb 5, 2004
4,627
Tartan 3800 Westport, MA
I have a remote coolant tank as well - there is no recovery tank attached to the manifold (the outlet is sealed). My boat came that way so I don't know if it's original or not but it seems to make sense.
Thanks for your reply. Yes, mine has two recovery tanks. I'm tempted to eliminate the one by the manifold, per Westerbeke. I'll have to find the right size plug.
 

jviss

.
Feb 5, 2004
4,627
Tartan 3800 Westport, MA
By the way, today I might replace my damaged and leaking "radiator" hose, hose from thermostat housing to heat exchanger. Wish I had that plug in hand!
 

dmax

.
Jul 29, 2018
493
O'Day 35 Buzzards Bay
I need to find a better plug as well - mine has a rubber "cap" held on by a hose clamp.
 
Feb 21, 2013
3,779
Hunter 46 Point Richmond, CA
........................So, should I do that, eliminate the coolant recovery tank near the engine?..........
So you have this set up with 2 expansion tanks with one pressurized and the other one not? Rather than make a recommendation based on my engineering experience I would consult Westerbeke directly for that answer to be safe.

Part 24177 Installation Note: "Metal tank used when the hot water tank (heated by coolant water) is located at or above the top of the engine. **When adding a tank to the cooling system change out the cap with that on the manifold."

1597415222573.png
 

Attachments

dmax

.
Jul 29, 2018
493
O'Day 35 Buzzards Bay
Can't double clamp, not enough room. I'm more worried about the rubber bursting, it doesn't look as tough as normal water hose.
 

jviss

.
Feb 5, 2004
4,627
Tartan 3800 Westport, MA
So you have this set up with 2 expansion tanks with one pressurized and the other one not? Rather than make a recommendation based on my engineering experience I would consult Westerbeke directly for that answer to be safe.

Part 24177 Installation Note: "Metal tank used when the hot water tank (heated by coolant water) is located at or above the top of the engine. **When adding a tank to the cooling system change out the cap with that on the manifold."

View attachment 183811
Both tanks are pressurized, and the "pressurized remote expansion tank" has a 13 psi cap while the manifold has a 15 psi cap, per the recommendation of Hansen Marine Engineering, and the note in the Westerbeke manual.
 
  • Like
Likes: sail sfbay
Feb 21, 2013
3,779
Hunter 46 Point Richmond, CA
Sounds like you have a well engineered system with 2 tanks unless Westerbeke advises otherwise.

I assume you have read this: Westerbeke, recommends "if any portion of the heating circuit rises above the engine's closed cooling system pressure cap, then a pressurized (aluminum) remote expansion tank must be installed in the circuit to become the highest point."

Interesting article on coolant recovery tanks: Understand Your Coolant Recovery Tank