automag

[huffdawg]

Does the automag have some sort of function that another brand of N.O. open zone valve like the honeywell V8043 5000
doesnt have?

Huff

 

[Gooserider]

Does the automag have some sort of function that another brand of N.O. open zone valve like the honeywell V8043 5000
doesnt have?

Huff

Not sure, but I think it is supposedly more suitable for the idea of being closed all the time except for the occasional power failure - less prone to getting stuck. Also I have heard that a conventional ZV can take a couple minutes to open or close, while the automag is supposed to have more of a "snap" action...

One thing that is definite, I see on the automag website that they specifically list overheat dump loops as one of their design applications - the other valves that I've looked at don't. If you have one that is listed for a dump-zone application, I don't see any reason why one couldn't use it instead of the automag, but I'd be a little hesitant if it weren't listed...

Gooserider

 

[chuck172]

I think any N.O. zone valve would work as a dump valve. I use the honeywell, no problems.

 

[hayrack]

An automag is a normally open valve. It is powered by 24 volt dc power not ac like a zone valve. It has a coil that magnatizes a plunger so when the power is on it is closed. It is spring loaded so when the power goes out it opens with one quick action. There is no valve that works better or is safer during a power outage. Every wood boiler should have one installed to dump into a zone higher than the boiler so it will gravity feed during a power outage. You can also use them for your individual zones. They are a very well built and reputable valve.

 

[chuck172]

The honeywell may not open in one quick action, but how important is that? If it takes 5 seconds to open, so what?

 

[sbleiweiss]

Hayrack,
You gave me quite a fright with that post. My Automag is getting 24V AC power...
Automag makes several series, the RI series which is the one I use accepts 24V AC.
They also have an AA series that takes 24V DC.
(broken link removed to http://www.automagzonevalve.net/products.php?section=products)
I am sure any NO zone valve would work as long as it opens on it's own when power is lost and is rated for continuous operation in the closed position.

 

[hayrack]

Sottb, You are correct about the newer designed automag that does run off ac power. I was referring to the aa like you mention. I have seen licensed solid fuel guys try to power the aa series with ac instead of dc and it does not work.

 

[Paso]

Every wood boiler should have one installed to dump into a zone higher than the boiler so it will gravity feed during a power outage. You can also use them for your individual zones. They are a very well built and reputable valve.

How have you accomplished this ? I seem to be drawing a blank on this concept??

 

[Fred61]

Hayrack,
You gave me quite a fright with that post. My Automag is getting 24V AC power...
Automag makes several series, the RI series which is the one I use accepts 24V AC.
They also have an AA series that takes 24V DC.
(broken link removed to http://www.automagzonevalve.net/products.php?section=products)
I am sure any NO zone valve would work as long as it opens on it's own when power is lost and is rated for continuous operation in the closed position.

I was under the impression that the Automag had a larger opening, thus allowing less resistance to the flow. Most zone valves have a very small orifice in the open position. Am I wrong?

 

[Gooserider]

Every wood boiler should have one installed to dump into a zone higher than the boiler so it will gravity feed during a power outage. You can also use them for your individual zones. They are a very well built and reputable valve.

How have you accomplished this ? I seem to be drawing a blank on this concept??

It has been discussed many times, (do a search on Dump Zone) and there are many ways to do this, but essentially you set up a zone of some sort of load that can thermo-siphon and is about 10% of the boilers rated output, and has no dips or loops that would act as a heat trap, connected via the automag to the boiler output and return. Often the power to the automag runs through an "open on rise" aquastat that is set to near the overheat temperature. If the power goes out, or the boiler gets to hot, power to the automag quits, it opens and the boiler heat is partly dissipated via the dump zone to keep it from getting to hot...

Gooserider

 

[Paso]

I have read many times about the dump zone / auto mag what I was having a hard time getting my head around is the words

" Zone Higher than the boiler so it will gravity feed "

Can't visualize that

 

[chuck172]

Zone higher than the boiler. Imagine the boiler in the basement, a radiator on the next floor up. A supply line to the radiator will pull hot water from the basement boiler and push it back down to the boiler through the return line. That is gravity flow. No circulator needed.

 

[Gooserider]

I have read many times about the dump zone / auto mag what I was having a hard time getting my head around is the words

" Zone Higher than the boiler so it will gravity feed "

Can't visualize that

I suspect the issue is the term "gravity feed" and the notion of water flowing "up" to an overhead zone... This is why I like to use the term "thermosiphon" for the concept instead... In essence the idea is based on the fact that when water is heated expands, so it's density decreases, and a given volume of water will weigh less - because the water molecules bounce around more when hot, it takes fewer molecules to fill a gallon jug at 190°F than it does at 100°F... The result of this is that hot water tends to rise, and cold water sinks...

The way this works in the old fashioned "gravity feed" or thermosiphon boiler systems, or a dump zone is that the boiler needs to be located at the bottom of the system, where it heats the water so that it becomes lighter and expands. In the meantime the water in the radiation loop(s) above the boiler is giving up its heat, and becoming cooler, and therefore heavier. The hot water from the boiler pushes up one side of the loop as it attempts to expand and rise, while the cold water that is at the top of the loop sinks down the other side to the boiler return as it wants to sink. It flows into the boiler in order to replace the hot water that rose out the top... One can get into debates about whether what drives such a loop is the hot water rising, or the cold water sinking, but really both forces are equally important, and the bottom line is you end up with a circular flow.

The boiler has to be at the bottom, or the zone has to be higher, or the water won't rise up into the zone, and you won't get any flow. If the zone was below the boiler, the water couldn't rise, as it would already be at the top of the loop... This also means that one of the design details has to be that there are no "heat trap" dips in the dump zone plumbing that would want the hot water to go down before it could go up again.

Back in "Ye Goode Olde Dayes" before circulator pumps and zone valves were invented, they designed entire heating systems to work on this principle - took very careful design and planning, only worked with certain building designs, and required large diameter (expensive) pipes and so on, but a well designed system was a wonderful thing, and some of these setups are still in use, and performing as well as they did when built... Nowadays, we mostly just use the approach with dump zones, which work the exact same way, except we stick an automag in the circuit to keep it from flowing except in an "emergency"...

Does this help you wrap your head around the concept?

Gooserider

 

[huffdawg]

I guess the automag will work as a normal zone valve in conjunction with an aquastat and a thermostat when the power is on?

Huff

 

[Gooserider]

I guess the automag will work as a normal zone valve in conjunction with an aquastat and a thermostat when the power is on?

Huff

Far as I know it should... Just need to make sure that it's wired up correctly so that it gets power shut off when the thermostat calls for heat, as it's an N.O. valve. Most ZV's are designed NC valves, and thus open when the get a call for heat, the automag is the opposite...

Gooserider

 

[webie]

I have been running an automags for my zone system since 1984 . So the question will they gravity feed if the power goes out ? Yes they will . Will they work when you have ups and downs in your pipeing , again mine does . My boiler is in the back of my garage with three bedrooms and a bath above on a single 3/4 inch loop . I am now running a solo 60 . 90 % of the time it wouldn't make a difference anyways as my boiler really only runs about 5 hours a day so that's 19 hours of big deal no power don't have to worry about an over heat . I am not sure that even as a thermosiphon that it actually could dissipate enough heat off of the boiler if say I was in the middle of a hard burn and the power went off . What we all have to hope for is that the fire dies from lack of a combustion blower and there is enough movement of water to keep it cool enough . Even that said as far as the upstairs zone opening and it starting to thermosiphon it takes some amount of time , Its not like a pump kicking in , chances are the boiler probably would heat up a lot faster than the siphon action could even start . Have I ever done a mock outage , yes I have . My storage tank was full and the boiler was in the middle of a cycle burn so it had been kicking in and out to satisfy the house , I waited till it was nearly maxed and ready for the combustion blower to kick out and shut down the breaker , In less than 15 minutes I was at 230 degrees and I got scared and turned the power back on . Now I know this was an extreme case scenario but we all have to test under these situations. I have had power outages and luckily they have never occurred under the worse case so I have actually seen the gravity feed start to work but it does take some time as the water has to be just the right temp in the loop to get it going , once it starts it seems to be pretty hot for the first couple of base boards and the end ones are barely warm. the other weird thing is it always reverses flow for me in my loop . One other thing I know is there is no way that my one loop could disapate nearly 200,000 BTU's . My actual dump zone is in my basement and it is tripped by an aguastat in the boiler set at 200 degrees and when it trips it cuts the power to my basement automag thus allowing it to open and it actuates the zone pump , this is my actual dump zone .
So as it stands I really don't worry about it all that much if the power goes out , There are times when I know we have bad weather coming . say Ice storm or very high winds , in other words higher potential of power loss , then I only burn when I am home . In the event even if I am sleeping My ups on my computer will go off . My biggest fail safe for all this is .
MY GENERATOR

I was told by my supplier that I couldn't get these anymore but after reading this thread I see the company is alive and well , Does anyone know a supply house where I can order a valve from or does a guy have to order these right from auto-mag as I will be needing to add another zone this summer and I much prefer to use these as they are nicer and easier to add then the couple of erie valves that I have .

 

[Paso]

Thanks Gooserider the light bulb went off with the words "Thermosiphoning" that I understand I just couldn't with the word Gravity as gravity is downward to me.

 

[webie]

Just wondering yet if anyone knows a place I can get a automag zone valve from , as my supplier says he cant get them ?

 

[Gooserider]

Just wondering yet if anyone knows a place I can get a automag zone valve from , as my supplier says he cant get them ?

"Google is your FRIEND"... Looks like they can be had at Amazon and EBay, probably several other places...

As to the question of how well the gravity flow works, yes it will work with some of the obstacles that webie claims, but they all will slow it down, and make it take longer to start, as you have a lot of inertia to deal with... OTOH, a "purpose built" dump zone loop is supposed to start almost instantly and flow quite fast, as the loop would be set up to optimize thermosiphon activity, rather than just "get away with it"... IMHO one of the more interesting ideas I've seen is to use the storage tank as a dump zone - as usual there are configuration requirements, but it seems like a good idea to take advantage of the existing hardware and put the heat where you can use it later... (Wouldn't work at a full burn with a fully charged tank, but you shouldn't be doing a full burn at that point to begin with...)

Gooserider