System Planning, Odds and Ends questions

  • Active since 1995, Hearth.com is THE place on the internet for free information and advice about wood stoves, pellet stoves and other energy saving equipment.

    We strive to provide opinions, articles, discussions and history related to Hearth Products and in a more general sense, energy issues.

    We promote the EFFICIENT, RESPONSIBLE, CLEAN and SAFE use of all fuels, whether renewable or fossil.
Status
Not open for further replies.

JP11

Minister of Fire
May 15, 2011
1,452
Central Maine
I don't suppose I NEED to know how all of this stuff works, as I am going to have a real plumber install. I certainly don't like to have things in my home that I don't understand. So a few odd questions.

My wood boiler is going to be in series. I'll go from the boiler, to 1000gal of storage. From the top of that storage the tanks will feed my current oil boiler, and all of it's zones. If the storage drops below 140, the oil boiler can take over for the home. (this is the way Mark from AHONA has explained it to me. Makes sense. He says we will keep my boiler hot, because it's not worth the thermal shock to let my oil boiler cool down)

Do people use a danfoss on BOTH supply and return? I see both for sale on Mark's site. Reading about them, they certainly have two separate functions. He talks about a "throttling valve" That "I THINK" is a ball valve in the return loop line. right? So that you can shut down the return loop once everything is up to temps?

In the "simplest storage" design. There is an expansion tank at the boiler, and another for the storage. So essentially you must have an expansion tank for the water in the boiler correct? In other words.. if there is 50 gallons in the boiler.. I would need 5 gal expansion tank that's plumbed in before the supply danfoss. That's to protect expansion of the small amount of water in the boiler and return lines. So when the boiler is cold.. the danfoss valves have it essentially have it walled off from the entire system... so it needs a small expansion tank.

THEN... the large 1k gal of storage needs near 100 gal of expansion.. and that would be plumbed into the system on the lines that go from the storage feed (top of tank) that go to the circulators that supply my home.

More questions.. I planned to have a ball valve and small line at the TOP of my storage. if for nothing else to have a place to vent air during filling. But in reality.. i probably should have some sort of permanent air vent on the top. right? Some cheap float type vent right? current oil boiler has one of those expensive bubble puller units.

Sediment SHOULD fall to the bottom of storage.. and I'll have drains on both tanks for occasional purging. BUT.. I've read some about filtration. Haven't really seen and products for that.

I know that it's a whole lot of random stuff in there... appreciate any thoughts, and would love to learn from anyone's mistakes. :)

I'm planning 1.5 inch copper from the boiler to storage. Anxious to get going.

JP
 
JP11 said:
I don't suppose I NEED to know how all of this stuff works, as I am going to have a real plumber install. I certainly don't like to have things in my home that I don't understand. So a few odd questions.

My wood boiler is going to be in series. I'll go from the boiler, to 1000gal of storage. From the top of that storage the tanks will feed my current oil boiler, and all of it's zones. If the storage drops below 140, the oil boiler can take over for the home. (this is the way Mark from AHONA has explained it to me. Makes sense. He says we will keep my boiler hot, because it's not worth the thermal shock to let my oil boiler cool down)

Do people use a danfoss on BOTH supply and return? I see both for sale on Mark's site. Reading about them, they certainly have two separate functions. He talks about a "throttling valve" That "I THINK" is a ball valve in the return loop line. right? So that you can shut down the return loop once everything is up to temps?

The Danfoss is usually only used on the return to the boiler for return water protection, but they can be installed on the supply output also depending on your system configuration. Most folks here have them on the return, I think. There is also whats called a diverting valve, and that pushes your water one way or another depending on the temp (Flow in to one port, out to two ports). This is different from the mixing valve, which has flow in to two ports, out to one port. A throttling valve is the ball valve installed on the line between your boiler supply and return (aka, bypass line). You adjust this valve to help regulate the flow to where you want it. Once set, basically forget about it, but you dont want to close it entirely.

JP11 said:
In the "simplest storage" design. There is an expansion tank at the boiler, and another for the storage. So essentially you must have an expansion tank for the water in the boiler correct? In other words.. if there is 50 gallons in the boiler.. I would need 5 gal expansion tank that's plumbed in before the supply danfoss. That's to protect expansion of the small amount of water in the boiler and return lines. So when the boiler is cold.. the danfoss valves have it essentially have it walled off from the entire system... so it needs a small expansion tank.

THEN... the large 1k gal of storage needs near 100 gal of expansion.. and that would be plumbed into the system on the lines that go from the storage feed (top of tank) that go to the circulators that supply my home.

You dont need multiple tie-ins for expansion. All of your piping is connected, and a pressure change in one part of the system will also appear in the other. So you can have one set of expansion tanks sized to handle all of the water volume in your boilers, storage, and piping. No need to have multiple tanks. The Danfoss doesnt isolate your boiler, since its only going to be on the return side. the supply side will be open to storage (Im assuming, havent seen your schematic), and as a result any expansion, contraction can happen there. If you have zone valves anywhere that isolate parts of the system entirely, thats a different story.

JP11 said:
More questions.. I planned to have a ball valve and small line at the TOP of my storage. if for nothing else to have a place to vent air during filling. But in reality.. i probably should have some sort of permanent air vent on the top. right? Some cheap float type vent right? current oil boiler has one of those expensive bubble puller units.

Sediment SHOULD fall to the bottom of storage.. and I'll have drains on both tanks for occasional purging. BUT.. I've read some about filtration. Haven't really seen and products for that.

I know that it's a whole lot of random stuff in there... appreciate any thoughts, and would love to learn from anyone's mistakes. :)

I'm planning 1.5 inch copper from the boiler to storage. Anxious to get going.

JP

Ball Valve at the top for venting during filling is a good idea. I suggest putting in a Tee at the top with a ball valve on the side leg, and a coin type vent on the top. You can manually actuate this when there is air at the top, and then close it entirely when all the air is purged. This way no chance of a leak or the auto-vent failing and sucking air on you.

Will all of your water flow through the "bubble puller" (aka spirovent)? If not, you want one on the outlet of your new boiler also. All your water should flow through one, just to be on the safe side.

I cant help you on the filtration thing, other than it cant hurt to have a Y strainer in there for system startup.

What size is your boiler? 1.5" copper can handle a lot of BTUs to storage.

Good luck, keep us posted!
 
Thanks

Yeah.. spirovent.. that's what it's called. A friend who is in the know saw mine and said.. wow.. you got a top of the line expensive one. Can't say I had any input in that.. but I did like the job my plumber did. Yes, all the water would pass that on the way to loads.

60kw boiler. My house at -10 was running about 100k per hour of load. At least that's my guess from using a hourmeter on my boiler.

So in theory.. half the output to storage, and half to heat the home if it's -10 outside. I can live with that. I wanted a large enough boiler to "catch up" if I'm down on storage and the house is calling at the same time. The big unknown is how much my wife will use it. I go away a week at a time. The payback is gonna be long if she doesn't like it.

I'm winning her over slowly.. she's helping gather and split.. I'm up to about 30 minutes of "help" at a time. She was raised that heating with wood is "dirty" and inferior. I'll keep working on her.

She's into the environment and animals.. and we have 70 acres of woods. Should be easy to show her once it's all running.

JP
 
My wife uses our boiler all the time when I travel for work, and she hasnt had any trouble at all. We are still working the kinks out of it, but its pretty bombproof so far. She is on board since she knows we can raise the temp in the house when we are on wood and not oil :)
 
Sounds like you plan to use as little oil as possible. If so I would have the boilers pumped in parallel rather than series. On mine the oil boiler has not been on all winter, so no thermal shock to worry about.

But if you plan to have the oil boiler running some every day or you have a tankless coil series might be the way to go.
 
I agree. I think with the lambda boiler and a good wood supply.. there shouldn't be too much to deal with. It's just the mental part for her I think. I'm going to eventually get her over to the dealer's to fire his setup. It's going in regardless! :) but I think she'll run it once it's in there and going. I go away about 15 days a month. With the larger boiler, and the storage.. I could have it fired when I leave, and plan to catch up when I get home.. she won't have to use it a lot. Dead of winter.. it's gonna need two fires a day.

JP
 
Sounds like you need about 3,000 gallon of storage. Just fire when your home and let it coast till your back.
I've been telling my wife I need to show her how to run our boiler in event I can't for some reason, but she
don't seem to interested in learning so I havn't pushed the issue. I don't do some jobs (womans work) and she don't do
others. (manly work) I'd never ask her to cut or split wood, but if she wanted to that would be fine.
 
  • Like
Reactions: Tennman
JP11 said:
Thanks

Yeah.. spirovent.. that's what it's called. A friend who is in the know saw mine and said.. wow.. you got a top of the line expensive one. Can't say I had any input in that.. but I did like the job my plumber did. Yes, all the water would pass that on the way to loads.

60kw boiler. My house at -10 was running about 100k per hour of load. At least that's my guess from using a hourmeter on my boiler.

So in theory.. half the output to storage, and half to heat the home if it's -10 outside. I can live with that. I wanted a large enough boiler to "catch up" if I'm down on storage and the house is calling at the same time. The big unknown is how much my wife will use it. I go away a week at a time. The payback is gonna be long if she doesn't like it.

I'm winning her over slowly.. she's helping gather and split.. I'm up to about 30 minutes of "help" at a time. She was raised that heating with wood is "dirty" and inferior. I'll keep working on her.

She's into the environment and animals.. and we have 70 acres of woods. Should be easy to show her once it's all running.

JP

How big is your home? 100k btu/hr would be a very high load for most residential installations. If your load is truly that high I don't think you're going to be happy with anything less than the largest boilers available (80KW) and substantially more than 1,000 gallons of storage. Unless, of course, your plan is to burn 24/7.

For reference I heat 3200 square feet and my load is on average 20,000 btu/hr +/-. My peak loads (below zero all day, zero sun) will approach 50k btu/hr +/- but I only have a handfull of these days in a normal year (zero so far this year). I'm heating with a 40kw boiler and 1,000 gallons of storage. On an average day I burn for 6-8 hours to heat for 24 hours.
 
My wife fires the Garn more than I do. As long as it is simple, I think you'll have no concerns. As the complication grows, needing to notice this or that and do X so it will work, it might have more growing pains.

Regarding plumbing the oil boiler in series.....do you think you will ever run it? I have my Buderus in series now, but I haven't burned a drop of oil since NOV10....and when I rework my piping to get the addition hooked up, I'm going to set things up so I can either go through the boiler in series or shut a few valves and then be in parallel. That way, I don't keep it warm, and whatever loss I have there, I won't. I likely will have to put another control on it for freeze protection....it sits outside in its own boiller shed. BUt then I have the option. The oil boiler will be piped as secondary feed into the primary loop. So, if the Garn gets cool, the oil can fire just fine to provide heat....and NOT heat up the 1500 gallons in the Garn! Just a thought.
 
I think it's realistic that I will still use the oil. Either DHW in the summer, or if the wife doesn't like to burn.

I'm not confident on the 100k per hour.. but the boiler ran 24 hours a day when it was -10

I'm figuring on .9gal/hr of my biodiesel mix (straight bio is about 118k btu per gallon) So I'm right up there.

heating 6k SF with about 1200 of that garage/utility room that's only 60deg. The rest 70. Lot of glass. All radiant heat.

Boiler was a bit dirty then.. so some loss in transfer.

JP
 
Well, I enjoyed re-reading it.... Necro'd.... Lol... Is that millennial speak for raised from the dead?
 
Status
Not open for further replies.