Moyer heat exchanger emptying

[ArtJ]

How full should the Moyer heat exchanger reservoir tank stay `normally?


My new heat exchanger has been refilled several times and is currently
nearly 2/3 empty. I believe the loss is going to the plastic overflow bottle.
I resealed the fitting on it with 5200 a couple weeks ago. Maybe it did not
seal correctly

I am thinking that the overflow plastic bottle is setting up a siphon and
I am thinking of temporarily removing the hose and simply letting overflow
go directly into the bilge. I have seen stains from the area of the overflow
so I know some antifreeze was going there and leaking out.

I am limited as to where I can place the plastic bottle. Currently it is
a about 3 ft outboard of the heat exchanger and at the appox. same
height. It can't be placed closer to center line as it would wet switch
panels. I wonder when boat heels if I siphon is being set up

There are no other leaks that I can find .

Comments and suggestions appreciated.

Art

[hanleyclifford]

Overflow bottle

Art - My overflow bottle is over a foot above the exchangers. I believe the bottle must be the highest component in the system. Regards, Hanley

[ArtJ]

Thanks Hanley

I will see if I can mount it a little higher.

I will also experiment with having no overflow plastic bottle and see if
less antifreeze is lost.

What is normal level in your reservoir? ( you may have mentioned this in
another posting)

[ArtJ]

Another possibility might be if the plastic bottle is totally sealed, top and
bottom, then if a siphon setup, it would only be effective until plastic bottle
totally filled, then when engine cooled,and boat righted or tacked antifreeze simply would flow back into reservoir , assuming
boat is "on the level" and seals are water tight ? (probably not totally feasible)

[ndutton]

Art,

If you're actually losing coolant it's definitely going somewhere. If it were simply going to the plastic recovery bottle, the bottle would be full. If the bottle is overflowing, the coolant would be in the bilge. Your post suggests neither.

You did say the exchanger was new. Is here any chance air in the system is burping itself to the exchanger, like from a water heater loop? If so, your falling coolant level should stabilize over time.

So, do you have a water heater? Is it or its connecting hoses above or below the heat exchanger fill cap? Do the hoses run in a continuous uphill path to the exchanger or is it more like a roller coaster path?

[rigspelt]

Art, I think the idea is that the heat exchanger should be full when cold, to avoid air bubbles circulating in the closed antifreeze system. When warm, expansion causes antifreeze to back up into the reservoir.

When I was installing our FWC system, I found these tips:

From Don at MMI: The very top of the fill neck of the heat exchanger itself should be an inch or so above the highest point in the engine's cooling system, simply to avoid water spilling out of the exchanger when you remove the fill cap.

From Tom at Indigo: The overflow bottle can be plus/minus one foot relative to the top of the heat exchanger.

I placed the reservoir so its bottom is just above the heat exchanger.

I filled the heat exchanger to the top and put the cap on. What I am not sure about is whether to add more antifreeze to the reservoir so there is always antifreeze in the reservoir. I can't find low-high marks on the plastic reservoir. Maybe I should add more antifreeze to the reservoir so there is about an inch in it and see what happens. Would be easier to check antifreeze level and top up antifreeze using the reservoir than by waiting for the engine to cool and removing the pressure cap on the heat exchanger. But if I do that, then when I remove the pressure cap for some reason, antifreeze will spill out of the heat exchanger.

[ndutton]

This recent thread might be of help, specifically posts 86 through 95.

http://www.moyermarine.com/forums/showthread.php?t=4016&page=2

Also, I would avoid mounting the recovery bottle above the exchanger reservoir. With the bottle above, opening the exchanger cap would gravity drain the bottle contents and potentially overflow the exchanger resulting in a coolant mess.

The coolant in the recovery bottle is drawn into the exchanger reservoir as it cools and develops a negative pressure gradient so a gravity flow mounting position is unnecessary.

[ArtJ]

Art,

If you're actually losing coolant it's definitely going somewhere. If it were simply going to the plastic recovery bottle, the bottle would be full. If the bottle is overflowing, the coolant would be in the bilge. Your post suggests neither.

You did say the exchanger was new. Is here any chance air in the system is burping itself to the exchanger, like from a water heater loop? If so, your falling coolant level should stabilize over time.

So, do you have a water heater? Is it or its connecting hoses above or below the heat exchanger fill cap? Do the hoses run in a continuous uphill path to the exchanger or is it more like a roller coaster path?

I have actually seen the stains from the coolant leaking from the plastic bottle That is why I recently sealed it with 5200. I see the coolant in the
bilge.
The Plastic bottle's bottom fitting didn't
really seal well was partially stripped. It may still be leaking.

More details of the cooling system are a newlly installed oil cooler from
Indigo, also a early style indigo mixing valve is installed.

[hanleyclifford]

Neil is right about opening the fill cap and spilling antifreeze via a drawdown from the the overflow tank. However, this is the price I don't mind paying in order to keep the system free of air pockets. If you want to get fancy, put a small shut off valve between cap and overflow tank - then very little antifreeze will be lost.

[ArtJ]

This recent thread might be of help, specifically posts 86 through 95.

http://www.moyermarine.com/forums/showthread.php?t=4016&page=2

Also, I would avoid mounting the recovery bottle above the exchanger reservoir. With the bottle above, opening the exchanger cap would gravity drain the bottle contents and potentially overflow the exchanger resulting in a coolant mess.

The coolant in the recovery bottle is drawn into the exchanger reservoir as it cools and develops a negative pressure gradient so a gravity flow mounting position is unnecessary.

Neil
The bottle is mounted probably a foot more or less above the
Heat exchange reservoir. The plastic line goes down near the
bottom of the engine( this is a tartan 34c with the engine mounted
in the centroid of theboat cabin partially down in the keel.
The plastic line then travels outboard thru battery compartment and then
thru a bulk head into the electrical console where it the bottle is mounted
outboard about 3 feet from exchanger and less than a foot above it.
I used this exchanger last fall without indigo regulator and oil heater.
At the time I could mount bottle somewhat lower than heat exchanger
inside battery compartment. Because of adding more batteries I had
to relocate inside electrical console (away from components for sure)

I have bleed the regulator per Indigo instructions. Again this is the
style of mixing valve Tom sold 10 years ago, which I never installed till last
fall.

Thanks

Art
PS I take it you bottom line is to mount it at the same level as reservoir

[ArtJ]

IF mounted at the same level, isn't a siphon setup when boat heels? Especially since bottle is 3 ft outboad of exchanger?

[hanleyclifford]

To get back to the questions in your original post. Yes, the exchanger should always be chock full of antifreeze. Yes, the overflow bottle should always have antifreeze in it but NOT be full. The overflow line under the bottle should always be full of antifreeze and must not leak. The only way I know to accomplish this is to mount the over flow tank at the high point of the system and make sure the line going from the overflow tank to the exchanger runs downhill without any uphill deviations. This configuration will allow the system to "burp" especially if you have heaters or other remote accessories. It is true that automobile systems have overflow tanks at the same level as radiator caps and do rely on pressure gradient to maintain a tight, full, air free system. If you can make that work for you, so much the better. Of course as you have already pointed out, sailboats heel and (hopefully) autos do not.

[rigspelt]

PS I take it your bottom line is to mount it at the same level as reservoir

Neil and Art, thanks for getting me to revisit this again. I really struggled with trying to figure out where to mount the exchanger and reservoir when I upgraded to FWC. Hanley, we posted simultaneously, and I revised this post given your thoughts. You favour option A for a boat, Neil favours option B. I'd like to make B work, but for now I have A.

I like the idea of mounting the reservoir so the bottom of the reservoir is below the top of the heat exchanger pressure cap. Maybe some day I'll move the heat exchanger down and inboard on the bulkhead, which will give me room to mount the reservoir lower so that I can remove the heat exchanger pressure cap without spilling antifreeze, but allow me to watch the antifreeze level through the translucent wall of the reservoir, and top up via the reservoir not the pressure cap. This will free up space and shorten the hose runs too. But, as Hanley points out, this has disadvantages, and maybe I'll leave this as they are.

I made up this little drawing to give us a frame of reference for this recurring discussion about where to mount the heat exchanger and reservoir.

[hanleyclifford]

Rigspelt - That system looks fine assuming the levels shown are the cold positions. Just make sure the level in the plastic tank is above the cap on the exchanger.

[hanleyclifford]

Rigspelt - Option "A" is superior to "B".