E30+ more fuel tank and water heater questions.

[mherrcat]

Just removed the hot water heater on my E30+ in preparation for replacing the fuel tank.

In the engine coolant supply/return lines to the water heater there is an accumulation tank. After removing the water heater I just closed the circuit so coolant would continue to run through the accumulation tank and back to the engine. This should work, right? I want to be able to continue to use the engine until the new fuel tank is ready to drop in.

Anyone have any tips on removing the plywood deck over the fuel tank that the water heater sits on? The five screws on the port side are easily accessible, but of the three on the starboard side, two are under a vertical panel with only about 1” of clearance. Any ideas how to access those screws without having to cut out part of the vertical panel?

 

[mherrcat]

Any thoughts on looping the coolant supply back to the engine after removing the water heater? Doesn't seem like it should be a problem, I'm just wondering about the accumulation tank.

 

[footrope]

I can't think of a reason for coolant to be plumbed into an accumulator tank, if that is really what you have. Usually the fresh water would be plumbed there so that the fresh water pump can pressurize the system and cycle less frequently. Is there more to this system than you've told us so far?

 

[Loren Beach]

I do not know that reasoning behind it, but on the M25 (21 hp) diesel engine on a friend's Ericson the stock engine coolant system had a separate tank mounted out from the engine. It was metal, and seemed to function like a reservoir, with its own pressure cap (I may have cap part wrong, since it's been years since I looked at it).
Not sure if the owner still has this same system in place.

Loren

 

[mherrcat]

What Loren describes is exactly what I have. It is shown on the E30 System Plan drawings available in the "Specs & Documents" section of this forum as an "accumulation" tank. There is also a note on the drawing that reads "Universal only" which I take to indicate its use with the Universal engine only.

When the water heater is taken out of the system you're left with two disconnected engine coolant hoses. So I figured in order to run the engine without the water heater installed I could just connect those two hoses together, thereby closing the system again. What I'm not sure about is how that affects the "accumulation tank" which is still part of the system. Probably not at all, but I was hoping someone else had a definitve answer.

 

[Meanolddad]

Hi
My 30+ does not have a hot water system. Regalus is a pretty basic boat. The accumulation tank is there, so I am pretty sure you can run without the water heater.
Hope this helps
Greg

 

[Brookelise]

Header tank

The tank could be a header tank. It's there to help prevent the engine from overheating if there's any blockage in the cooling system at the water heater. The blockage can be caused by air trapped in the water heater when the heater is mounted higher than the engine. The header tank helps remove air from the coolant system. You can do a search on "coolant header tank diesel" to read more about it. If you bypass the heater -- "closing the circuit" in the coolant system, as you wrote -- you can run the engine. The only difference is that you're no longer running coolant through the water heater to heat the water in it.

You can also winterize the boat by bypassing the heater and draining it, and you can buy a kit with valves and hoses to do this each winter easily without disconnecting hoses. (It's in the West Marine catalog under Water Heater Bypass Winterizing kit.)

All the best,

Brooke

 

[mherrcat]

The accumulation/header tank is actually located about level with where the upper coolant connection was near the top of the water heater. The water heater itself was located higher than the engine. (It's a Raritan water heater, if that makes any difference.) I refilled the coolant (it wasn't completely empty) via the pressure cap on the engine and the pressure cap on the accumulation/header tank. Should I be concerned about air in the system when I start the engine?

I'm going to check Calder's book to see if there is any mention of the header tank you describe.

Thanks for the info!

 

[mherrcat]

Did a Google search on "coolant header tank diesel" and came up with this from a Beta Marine dealer site:


Beta Marine now offers a remote mounted engine coolant tank, made of heavy cast aluminum, that is primarily designed to be used when a separate hot water tank is installed in the boat. The hot water tank will heat and store domestic fresh water for showers and cooking whenever the engine is running. In many water heater installations, the hot water tank is mounted higher than the engine, resulting in air being trapped in the tank. This can lead to the engine overheating since the trapped air acts as a blockage in the engine's cooling system. This new "header tank" is equipped with a pressure cap, just as is your car's radiator, to regulate engine cooling system pressure. The pressure cap also works as a valve to bleed air from the cooling system. It can be mounted in any convenient location on a bulkhead that is higher than the domestic hot water tank. Catalina 30 sailboat owners will want to install this header tank in the port cockpit locker where it can be easily reached for checking the engine coolant level.

This header tank can also be used when the engine's standard pressure cap is inaccessible, as it can be on some boats that use a V drive transmission. The Pearson 323 is one such design that can benefit by mounting the header tank in a cockpit locker. The header tank also increases the capacity of the engine cooling system.

Dimensions - 8" long, 7.5" tall, protrudes 4.3" from the bulkhead. Is easily attached to the bulkhead with 4 screws. The addition of a separate coolant recovery tank will ensure that the header tank remains completely filled with coolant and will also purge the engine cooling system of air pockets.

Here's how the system works -

As the engine warms to operating temperature, the fresh water coolant expands and pressurizes the cooling system. When the pressure reaches 15 psi, the pressure cap valve opens, maintaining the correct system pressure. As the engine is operated and coolant freely circulates, trapped air will find it's way to the high point of the cooling system, which is this header tank. The air will be bled off when the pressure cap valve opens. This occurs periodically while the engine is running. If a separate coolant recovery tank is installed, any coolant that's expelled from the header tank will accumulate there. When the engine is shut off, it slowly cools down creating a partial vacuum in the engine's cooling system. The pressure cap valve now opens under this vacuum which causes coolant to be sucked from the recovery tank into the header tank.

The net effect of this action is to purge all air pockets from the engine cooling system which otherwise may cause localized engine overheating. Having the engine cooling system completely full and purged of all air, helps maximize engine life and reliability. To check for the correct coolant level just look at the coolant recovery tank, as it's made of translucent plastic. This refinement is highly recommended for any fresh water cooled engine.


Thanks again!

 

[Brookelise]

Header tank

The header tank is designed to remove air from the coolant system. Your coolant system might have a valve to let air out of the system, on a coolant hose near the engine, but with the header tank, you don't need it -- and shouldn't need to use it.

Do you have a separate coolant overflow tank next to the header tank or near the engine? It's a clear, square plastic tank with screw-on metal cap. That's where the coolant should be added when you're topping it off. When you first fill the coolant system with coolant after the system's been drained, though, you'll have to add coolant where you said, at the manifold (with the pressure cap) and header tank (with the other pressure cap).

You should monitor the coolant overflow tank (the plastic tank) for the coolant level. You should keep the coolant at a level from a third to halfway up in the overflow tank.

Just so there's no confusion, there's the metal header tank with the pressure cap, and then there's the clear plastic overflow tank with a screw-on cap (not a pressure cap, but an ordinary screw-on cap). Once your coolant system is filled, you shouldn't have to add coolant anywhere but at the plastic overflow tank. (You might need to add some from time to time.)

-- Brooke

 

[mherrcat]

Thanks for the further clarification.

The plastic overflow tank is located next to the engine. It is located higher than the engine; does its position really matter? The hoses from the pressure caps enter the overflow tank at the bottom, so it seems like being higher than the engine would be fine.

The overflow tank is the same system found on most cars. Once the system is full and "closed" coolant only needs to be added via the overflow tank.

Some final questions; why the need for two pressure caps? And should they both be rated for the same pressure?