Bringing boiler and storage back online

[stokes79]

So it's getting cold enough to warrant the wood boiler and last season got great results with top of storage tank temps at 200 f and bottom near 180f. With that I only have to charge storage every three or four days

My question is I have got it up to 180 and notice my pressure is higher than last season. When I started 1000 gal storage was 50 f and I have 80 gallons expansion just thinking when water was that cold all summer my auto fill might have let in more gallons to heating system if it dropped under 12lbs
Does anyone know if I have roughly 1050 gallons total and want to operate at 120 f min to 200 f max how many gallons I should remove to stay away from 30psi pop offs going pop?

 

[stokes79]

I just bled roughly three gallons off manually with pressure relief valve that was dripping a bit and it dropped to above picture

 

[maple1]

Do you have a bladder or non-bladder expansion tank?

Ideally in my world at least I'd have started when cold with an empty expansion tank and full water tanks with both pressurized to 10psi. Open the connection between them & start burning. What was your starting psi? Your expansion tank might have taken on some water in the off season, and required bleeding. The problem with just draining water off when it's hot is it might lower your psi, but won't do anything for maximizing or increasing your expansion air volume.

 

[stokes79]

They are bladder tanks and I don't know the psi. I have two tied into storage tank totaling 80 gAllons. So if I drain ten gallons and keep it above a hundred f I shouldn't have to worry about over pressure since it hopefully won't go back down to 12 psi until late spring or whenever im done burning

 

[maple1]

I can't say for sure, but 80 gallons expansion seems marginal to me for your storage.

Hard to tell what's wrong without a guage on your expansion tanks. Can you check them with a tire guage? One of your bladders could have sprung a leak. If you've got 20psi at 200f like your guage is showing (is that your boiler or storage?), you should see quite a big pressure drop when things cool off to even say 170f if you've lost expansion space to being waterlogged. You really should isolate your expansion tanks & drain all the water out of them then pre-charge with air to whatever your system psi would want to be at the temp it's at when you do that. Say if cold 10, if hot 20? But it might be hard to tell if you've got water behind your bladder from a leak by draining the water out the bottom - unless you leave the drain open for a while. If you have a valve to check air pressure with & water comes out of that, you've definitely got trouble.

 

[stokes79]

Tire gauge is reading same as boiler and no water came out I thought I read on here several places 5% expansion I put in 8% to be safe

 

[lotawood]

Is your 80 gallon acceptance or expansion tank total?
I'm trying to figure out what I would need for future storage. I got a sx-160v extrol that has 46 acceptance and 86 tank size.
I assumed the 5-8% rule was acceptance.

 

[NP ALASKA]

I agree the expansion tank sounds to be on the small side.
I am currently installing and everything I have researched over ht e past 3 years before taking the plunge and 10-12% for planning purposes. As I understand it you can not have to much expansion.

I have 1250 gallons and was planning for to sx-110's I have since up graded to sx-160's. I plan to add another 1000 gallons for a total of 2250 and will add another 160 totaling 3.

Any I have seen most folks with 1000 gallons of storage are running two SX110's

Best regards

 

[mikefrommaine]

(broken link removed to http://www.watts.com/pages/support/sizing_ET.asp)

This calculator let's you figure the size of tank needed.

 

[Clarkbug]

I would be willing to bet you are correct in your hunch, that over the summer your autofill put more water in your system, and that is causing the issue you see now. When I first filled my system I overdid it, and had my pressure relief blow off on my a few times when I had my storage fully charged. No issues since then, but over the summer the pressure was really low. I just shut off the autofill, and charge my storage before letting the house circs kick in.

 

[maple1]

I have an autofill setup on mine, but it's valved off. I just moved it over from my old boiler. My old one had been turned on all the time, but the past few years I had it turned off after I had a problem with a pressure guage one time.

I just watch my pressures - if it gets looking too low, I'd open the valve to the autofill & let it gradually let some water in.

My line of thought is, with all this large volume of water under pressure - if I have a situation develop that the autofill would suddenly need to be doing its thing, it would be the early stages of a serious flood going on, and the last thing I would want is my well pump adding to it. I think even if there did happen to be a fire going at the time.

 

[Clarkbug]

I follow the same procedures as you maple, and have my autofill turned off. I just make sure Im up above 10 PSI when my tanks are cold, and if I havent been, I add a little more water. Lately Ive been getting some air in the top of the boiler (I purge it through my overheat loop), so Ive had to add a little water now and then.

 

[JP11]

I had never thought of leaving my autofill off.

My oil and wood boiler are both located within feet of a 4" floor drain. So I guess I really shouldn't NEED to shut the autofeed off.. right?

JP

 

[maple1]

I don't have an oil boiler anymore (do have an electric), and don't have a floor drain - so situations do vary. But I do now have a 660 gallon reservoir of makeup water in case something does go seriously wrong & there's a fire on. I do think it's a real possibility for the spring to weaken in the autofill thingy and let the pressure creep up over time - or a piece of dirt to get in it & not let it close tight if it does open to let a bit in.

 

[stokes79]

Thanks everyone I will look into shutting off autofill at least during wood season!