Storage tanks in place!
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Gasifier
Minister of Fire
Very nice nrford. I am close to the same stage you are at. Just beginning my install. Good luck and keep us posted. How much storage is that man? How did you figure out how much you needed for expansion?
woodsmaster
Minister of Fire
woodsmaster
Minister of Fire
Being on top I think it should work. Do you Know how many gallons total with boiler and plumbing.
jebatty
Minister of Fire
Very nice setup. 10% should be fine with plenty of safety factor. My rule of thumb for 32F-200F has been 5%, which still is more than actual.
Gasifier
Minister of Fire
Are you doing everything with the install yourself? What did you put under your first tank on the bottom to cradle it?
ewdudley
Minister of Fire
jebatty said:
Five percent is fine for an open expansion cistern, but for a closed tank or a closed diaphragm tank it is unlikely to be enough. FWIW water's maximum density is at 4 degC / 39 degF.
--ewd
woodsmaster
Minister of Fire
I would listen to mr dudley who is a very smart man. I have a 125 gallon expanshion tank on my system of around 1,100 gallon total and wouldn't want any smaller. If open expanshion disregard statement.
Gasifier said:
Used tank legs plus a 8" I beam. I will do all the plumbing myself as designed by Engineer and salesman Brian. Going with an Effecta 35kw lambdz controled boiler.
jebatty
Minister of Fire
Need to be a bit careful in mixing apples, bananas, and oranges, errr, open expansion tank, closed tank with air space, and bladder pressurized tank. 50 gallons (5%) expansion for a 1000 gallon system still is enough if the expansion tank will accept 50 gallons, so the 100 gallon recommendation for nrford leaves plenty of safety factor. I have 46 gallons acceptance in my pressurzed bladder expansion tank on my 1060 gallon system, and it is enough. I'm not sure we know whether the 100 gallon expansion tank of nrford is an open tank or a closed tank with air space; for sure it is not a pressurized bladder tank. Either way it should be more than adequate for a 1000 gallon system. If I'm missing something, let me know.
ewdudley
Minister of Fire
jebatty said:
Acceptance volume (the apple) must enough to accommodate the maximum expansion, about four percent would normally be sufficient. But while adequate acceptance volume is necessary, it is not sufficient; the tank volume (the orange) itself must be large enough as well.
For instance, Amtrol offers the SX-90V, SX-110V, and SX-130V, all of which spec an acceptance volume of 34 gallons, but they are not interchangeable just because they share the same diaphragm subassembly.
https://www.hearth.com/econtent/index.php/forums/viewthread/56576/
The OP with his expansion tank at the top of the system would likely only need seven percent, assuming a couple psi of pre-charge.
--ewd
woodsmaster
Minister of Fire
I'm sure brian Knows what he's doing. On my system I have the fill valve set at 12 psi. I filled my tanks with 55 deg F water and when I heat them up to 195 I have around 28psi. Thats why I was thinking a hundred gallon might be a little small.
jebatty
Minister of Fire
I'm planning a new install with roughly 2000 gal. storage, so this is of interest to me.
The only reason to precharge that top expansion tank is to balance against an automatic fill valve set at 12psi correct? Would it not be better to run the precharge and auto fill at as low a pressure as possible - like 5 psi? Your effective useable volume in the exp. tank is going to be greater with a 5 - 30 psi min/max than it will with a 12/30 min/max.
Under normal operating ranges ( 140 - 180* ) the system pressure should still land in the teens or low 20's which is plenty to prevent any pump cavitation issues.
It would seem the key to a non-bladder closed tank is a sight gauge so you can see that your water level is right at the bottom of the tank with a cold system.
Also - why would one want an automatic fill valve at all on a system with large storage volume? Assuming the feed to the boiler is off the bottom of the tanks, if you had a leak you would have to lose all 500, 1000 or 2000 gallons of water before you ended up with a dry boiler. Personally after the first 2000 gallons of water dumps into my basement, I'm not excited to have much more added....... even if it does mean my boiler is shot.
The only reason to precharge that top expansion tank is to balance against an automatic fill valve set at 12psi correct? Would it not be better to run the precharge and auto fill at as low a pressure as possible - like 5 psi? Your effective useable volume in the exp. tank is going to be greater with a 5 - 30 psi min/max than it will with a 12/30 min/max.
Under normal operating ranges ( 140 - 180* ) the system pressure should still land in the teens or low 20's which is plenty to prevent any pump cavitation issues.
It would seem the key to a non-bladder closed tank is a sight gauge so you can see that your water level is right at the bottom of the tank with a cold system.
Also - why would one want an automatic fill valve at all on a system with large storage volume? Assuming the feed to the boiler is off the bottom of the tanks, if you had a leak you would have to lose all 500, 1000 or 2000 gallons of water before you ended up with a dry boiler. Personally after the first 2000 gallons of water dumps into my basement, I'm not excited to have much more added....... even if it does mean my boiler is shot.
woodsmaster
Minister of Fire
700renegade said:
Yes you could start at a lower psi to possibly use a smaller tank. A sight glass would about be a must. I use the original float gauge in the 124 propane tank. I have the fill valve becouse it was a relief valve/ fill valve combo I got for the price of just a relief valve. I'm not worried about it flooding my basement becouse its in a shed 100' from the house. I suppose If a line in the house broke it would still flood the house with or without the fill valve. After 2000 gallon in your basement a little more wont hurt anything lol.
woodsmaster
Minister of Fire
The pressure in a system also helps the water get to the second and third floors. Not certain on the requirements but know it is needed.
Will
Will
My system with storage will be around 1100 gal and I plan to use a 250 gal propane tank mounted vertical for expansion. My thought was water level would be about a 1/4 high when cold and about 3/4 at hottest worst case (ie. about 125 gal acceptance). Isn't an air bubble necessary? Going to read EWDUDLEY's link on this stuff again.
woodsmaster
Minister of Fire
huskers said:
250 is more than enough. When cold you only need a little water in the bottom, but with a tank that big you could fill it 1/4 of the way and still have plenty of room for exp. You could precharge to 12 or whatever you need and not gain a lot pressure becouse of the size of the tank. It would never get over 1/2 full of water. Yes you do need some air bubble. There are a couple old threads on this subject that go into more detail.
Was pondering the size of my expansion tank. Using measurements of tank and being conservative it comes out to at least 125 gal.
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