Vented vs Non-vented system

[veggie]

Hi Guys,

I'm getting ready to tie in my steel heat storage tank.
Can I get some opinions regarding the use of a vented vs. non-vented system?
In one case I use a standard vented overflow bottle.
In the other case I use a non-vented fill cap and an accumulator bottle.

In both cases the system is not pressurized (other than the natural expansion of the fluid and blanket gases).
System temp will be maintained at 180f max.

I suspect a non-vented system would be better at reducing oxygen contamination (corrosion), but the vented system is easy and cheaper to build because I don't have to buy a $90 accumulator tank.

Or perhaps it doesn't matter either way ?

two options shown below....

thanks,
veggie

[mobile_bob]

do a search on ebay for "amtrol"
there should be several tanks to choose from, and they are usually very inexpensive

bob g

[veggie]

do a search on ebay for "amtrol"
there should be several tanks to choose from, and they are usually very inexpensive

bob g

Can do Bob,

What's your opinion on vented vs Non-vented ??

[LowGear]

I've read a couple of threads about Lister (oids) not being very friendly to water jacket / head gasket pressure.  I'm guessing the non-vented systems is going to 15 psi with little trouble as the water temperature climbs from ambient to 180 degrees.

Casey

[mobile_bob]

i like a closed system, and a 7lb pressure cap, with recovery tank, just like your car

now for a heating system, i would use one of those little amtrol tanks and a pressure relief
set to the same 7psi.

the listeroids should handle 7lbs, the two orings are good enough for that and more, the liner protrusion
will have to be kept under .005" so that the head gskt doesn't weep all over the floor though.

and i would treat the coolant with dca fluid and use the little test strips to monitor the condition of the coolant.
especially given the variety of dissimilar metals involved, castiron block, steel pipe, copper/brass fittings, stainless or aluminum
heat exchangers etc.

fwiw, that is likely what i would do at the very least

bob g

[Lloyd]

Electrolysis...from the dissimilar metals is  the least of your worries, in an open sys.

Oxygen is the big bad boy...in a cast iron sys..by at least 10 times elec....

Especially in hydronic sys, that also use a cast iron boiler...that's why  no warranties unless you use copper or alum/pex.

As Bob say,

7lb cap in a closed sys..at the very least

[mobile_bob]

as i see it the weak link in these systems, is the engine cooling system,

even a poorly designed engine, with substandard quality parts if put together correctly should handle a closed system with
a 7lb cap without worry.

my 195 is running with a closed system, 7lb cap and i have had it up to 260 degree's F "once" because of  my not checking the pump/fan circuit in testing, the system held up just fine even though it was venting live steam from the overflow tank.

that was certainly exciting, and i expected to have had a head gskt failure, but it held up just fine

don't want to do that again of course, and would rather not have done it in the first place.

and yes the automation system will have an over heat shutdown capability

as for a tank system, and boiling, i wouldn't worry much at all about that for a lister or a changfa, that is how they do a lot of cooling
phase change takes away a butt load of heat. if you cover the open top tank with a piece of plastic sheet and put a small rock on it
so that the water can condense and flow back down toward the inverted peak caused by the rock and drip back there should be little or no water loss unless the system is just too small for the engine.

i also wonder if one could simply drop a small car radiator down inside a 55gallon drum that is used for a cooling tank, and run water through the radiator to take the heat elsewhere and have a degree of separation between the two systems,
if not a car radiator, perhaps an A/C condenser core?  they are good for a couple hundred psi so as long as the water inside the
condenser was under household pressure there would be no chance of getting antifreeze into the drinking water,
any leak would be forced by city water pressure into the engine coolant drum and not visa versa.

the principle is good enough to keep sewage from entering the city water mains, so long as there is pressure nothing can enter the pipe that is under the water pressure at least.

getting back to the subject at hand,

probably the best for the engine is to follow the direction of radiator manufactures and the oem's, they in some cases spec distilled
or demineralized water for the cooling system, as well as a good antifreeze with the requisite corrosion inhibitors.

if your going to use a 55 gallon drum, it ought to be filled with rain water which is cheaper and have dca fluid added if not antifreeze
if needed for freeze protection.

next we step up to ebullient cooling systems



bob g