Greenhouse boiler question

Joebif

I have a aquaponic greenhouse that I am building, I am am now putting in a hot water heater and boiler set up.



In the setup I am using TACO Z075C2 zone valves, TACO

ZVC406-EXP-2 controllers and TACO 0013 variable speed pump. I have several fish tanks that will have aqua stats on them as well as Plant troughs along with 1 radiant floor in the Utility room. I am using a home made wood boiler for the hot water source and a 50 gallon hot water heater for backup.



I was thinking of having the wood boiler plumbed in series so if the wood boiler got to low on temps the propane boiler would kick in and take care of everything.



I understand that a wood boiler like I have will just put out heat until the fire goes out and want to know the best way to use it.  I have read about water storage tanks that the boiler heats and then the main system gets its heat from it.  I have also read about boiler dumps. 



I can use a dump in a way of having a fan coil heat exchanger set up in the greenhouse so if the boiler gets too hot it will turn this on and let go of the extra heat (which will help keep the plants warm).



The boiler I want to make is a 55 gallon barrel on its side with copper coils in it. So I know I need a way to get the heat out of it if nothing is calling for heat so I will not burst pipes.  I have a relief valve on the main system so this will help but would rater learn how to set up the dump.  The boiler will be in the greenhouse so it will also add to the heat needed at night.



What do I need to get and learn about to be able to use a dump valve with my ideas?

Al Letellier_21

greenhouse heat

Based on the insurance work I do, I have to ask you these questions:

--Where is this located?

---Is this private or commercial use?

---Is it legal (let alone safe) to build your own boiler?

You find find it tough to get advise here due to these questions. What you ask about a dump zone would be easy to answer, but the liability door is wide open if you are building your own boiler.

Just my two cents worth !!! Please be careful and check with your local authority and insurance carrier before you proceed. I"ve seen claims denied because of DIY boilers or improperly installed equipment by unlicensed or untrained personnel. Thank God I haven't seen any serious injuries but have seen a lot of property lost and claims denied for reasons like this.

I don't want to discourage you as it sounds like a great project and I wish you well with it....just be careful!!!

lchmb

recommendations

I would like to add that your project sounds like a rather important under taking to you. With that said, I think you would be better off to  purchase a manufactured wood boiler for use in this project. If something were to fail on your own home made system and fail in January do you really want to be out there trying to fix it before it freezes solid?

Let alone the liability factor that Al pointed out...Scary stuff nowadays...

Joebif

Boiler/wood stove

First to answer AL.



This is located in the country outside Denver.

It is private.

It is a wood stove made out of a 55 gallon barrel. It is legal to build a wood stove.



I have plans to add a pool heater to it that will have copper tubing placed inside of it.  This wood stove is in a greenhouse that will be used to heat the greenhouse with the radiant heat it provides along with the water running through  the copper tubes. The copper tubes are going to be hooked up to an existing hot water propane boiler set up and has the proper pressure relive valves that a boiler has.



The idea then is to have a aqua stat on the copper pipes to read the temperature of the water running through the wood stove so when it gets to hot would open a dump zone(preferable a fan/coil in the greenhouse to just give it more heat). This wood stove would be running at night only. No one lives in or around the greenhouse so the liability issue would not be there. I could loose some plants if the copper pipes broke due to a boiling condition. I may also just wrap the copper pipes on the outside of the wood stove several inches away from the body to help in not getting the water that hot.  I only need 120-125 degrees from it to use it in a radiant floor and fish tanks.



I want to also add a battery back up to the system so in case the power fails I still have a pump that would continue to work to keep the system working. If there was anything else to do or use to help in this I will. I heard of a normally open zone valve that is closed when the power is on and then opens when the power is off but want to get more info on how they work.



I do not have 5 or 10K right now to put into a wood boiler and a storage tank so this will really help. The propane system is there so if something freezes up it still works with out it because the boiler will feed the propane system and if the water temperature is not 120 the propane system does what it needs to to keep everything going. The propane system is right now the main system so I am just adding free heat to my greenhouse because I have a lot of wood all around me. I just have to cut it and bring it to the greenhouse.

lchmb

legal

It's legal to build a wood stove, but how about a boiler? And of course as Al pointed out, if something (hope it never does) goes bad will your insurance company accept any claims against you? Sorry to say liability is scary nowadays. Best of luck in your project, it sounds fun in some ways...

Jean-David Beyer

Legal wood stove?

I do not know the codes for stoves, or any others for that matter.



My brother in law had a commercially built wood stove (not a boiler) in one room in his house in Canada (Ontario). It was on a solid brick platform about one foot high above the floor of the room. The wall behind it was brick too. It had a vent that went straight up to the ceiling and on out. After 20 years or so, he was told he had to replace it because it no longer met code. Also, it needed to be further away from the brick wall, too. So he did all that, but thought the rules were pretty silly. He is not a heating contractor either (teaches  graduate computer science at the local university). He figured if it had not started a fire all the time he had it, it was not likely to start one later.



My guess is that codes vary between jurisdictions and from one inspector to another.

Mark Eatherton

Been there, done that and have the scars to prove it...

Copper, while being an excellent heat conductor, in and of itself is not a good choice as a heat exchanger for a solid fuel fired appliance. It will melt and collapse in the presence of intense energy, like is found in the combustion chamber of a barrel stove.



I've even seen them put on the outside of the stove, and still suffered some pretty serious degradation.



If you are going to jury rig something together, let me suggest a safer, but probably still not totally legal way.



Take a Buderus (or other equal brand of cast iron 3 pass boiler) and take the exhaust gasses from the oil drum heater, and plug it into the combustion chamber of said cast iron 3 pass boiler. You will have to have a Tjernlund draft inducer on the outlet of the cast iron boiler, but it should have the ability to overcome the pressure drop of the flue gas passages on the cast iron boiler. And the cast iron can certainly withstand the intense energy from the drum heater. Buderus actually manufacturers a solid fuel wood boiler.



With you being in the Denver area, I just happen to know a guy who has a used version of this very boiler available for sale. And I am fairly certain that for a fee, he will deliver it to its final resting place. Heck, you might even be able to convince him to pipe it up for you... (You owe me lunch Dave :0))



Regardless, using wood is a labor intensive, dirty job. Cutting, chopping, hauling, stacking, hauling, stoking, hauling and disposing of ashes. I don't think most people realize this until it is too late.



I plan on doing this in Heeney on my cabin, but I don't (won't) live there full time. Only on weekends, and everything dirty is being kept outside, where it was meant to be.



Contact me off line if you want more information on the Buderus boiler.



ME

Joebif

Valid points

You all have valid points.

I am in a greenhouse not a home but I will take this as a sign that I should not go down this road and build this then. I will save up and purchase something else like maybe a outside pellet stove boiler or wood biomass boiler so I can burn it all outside.



I will monitor this post and see if there are any other comments but it looks like for now it is not a good thing to do.

Joebif

Building Inspector

I just got off the phone with my building inspector and he said what are you guys talking about.  He said that my propane hot water heater is all set up just to heat water and that it has what it needs to be safe. I am running it at 120 degrees. I also have all the necessary boiler safety features on my system but do not have a boiler in it.



He said that I am not building a high pressure boiler with the wood stove and that it is a low pressure system.  I am just running water through it with no high pressure and that my pump will probably run all night long in the winter and the aqua stat on the fan coil set at 180 to make sure it would not boil over would for sure keep the pump running all night.  He said that the worst thing that could happen if I had a power failure would be that my pipe in the stove would bust and the wood fire would go out and I would have a mess to clean up. If I had a power back up that would not be an issue.



IS HE WRONG?

Al Letellier_21

greenhouse "boiler"

Don't know your inspector or his qualifications or experience but if he thinks that's the worse thing that can happen....I'd be looking for advice somewhere else. Please listen to the pros, especially someone like Mark and those of us who have been there and seen the results.

All I can and will say from here is good luck. Your decision, your results, your possible consequences.

lchmb

do yourself a favor

Look into the pellet stove..Look online for any deals..i know of one customer who had a pellet stove installed and decided against using it. He's looking to sell it at a loss. It happens all the time and would be far safer for you in your endevor. Someone in your area may have one for sale cheap and just be a matter of installing.

Research boiler failure's and see some of the nightmares that have happened over the years...You dont want to make that list.

Joebif

boiler or a woodstove

Is my idea a boiler? Or is it a wood stove with a heat exchanger?



You are are all saying that I am making a boiler but is it? I can see that if I were to make a boiler and have made something incorrectly then it will be a major problem.



The people that are selling wood stoves on-line with heat exchangers running through them with pipes in them coming out the back or the guys selling U style pipes to retrofit a wood stove to heat water are all wrong and illegal and should not be doing this?



Maybe I used the first topic "Greenhouse boiler question" was incorrect and it should have been "Greenhouse wood stove question" instead.

Joebif

To Mark

Mark you mentioned a safer way to do this and not use copper. I have, like I said in the post above, seen heat exchanger pipes for sale made out of stainless steel . This would be safer than copper. 



The only reason I was looking at copper is because I saw a website on-line where they are selling pool heater plans using this to add heat to a pool. It was a wood barrel stove with copper running through it.



There is also another website where they are selling wood stoves that look like they have 4 black pipes running through them to be used as a heat exchanger with connections on the back to make warm water.



Even the old stoves that were used in the home to cook on and heat the home and are still being made to this day have the same thing were water flows through it and warms the water. Are theses boilers or heat exchangers?



This is all I want to do is pass water through a heated wood stove and utilize the warmth I get from its passing to go to my hot water heater so it does not have to heat all of the water.

Rod

A Boiler is an Enclosed Vessel in which You Heat Water

I think you're getting hung up on the word boiler and thinking of a boiler as being  a train locomotive boiler or the type you would find in a ship like the Titanic. By definition, a boiler is any enclosed vessel in which you heat a liquid, normally water. This can be a pot on the stove (pressure cooker), or a stove with a enclosed heating coil, or a tank for domestic hot water or a hot water/ steam boiler for heating.

Keep in mind that when water turns to steam it increases in volume 1700 times. (1 cubic inch of water makes 1 cubic foot of steam)    In some situations this can happen instantly, if this happens in a confined space without a proper safety outlet,  "burst" is probably too mild a word to describe what can happen then.

My home is heated with a steam boiler that runs at a maximum of 1 1/2 PSI.  It has a pressure control that shuts off the burner (heat) when the pressure reaches 1 1/2 psi. If for any reason the pressure controller fails ( on some systems there is a second "back up" controller) there is a safety valve which will open at 15 psi. If the boiler runs low on water (a very dangerous condition) there is a Low Water Cut Off device that shuts off the burner (heat). I mention all this so you can see there are (need to be) multiple layers of safety designed into the modern boiler system. 

In the days of wood/coal fired boiler there were a lot more boiler explosions as there wasn't a way to quickly shut off the heat when an emergency situation occurred.

Do a search on this website for "Boiler Explosions" and you'll find a lot of interesting info.

The other people who have replied to you are VERY experienced pros in both hot water and steam heating. They are politely telling you to be very careful as there are genuine safety concerns involved which need to be addressed.    "Mickey Mousing" a boiler of any type is sure way to become a candidate for the Darwin Award.

- Rod