Controller questions

[Rigatoni]

Hi all. I have a Biasi 3wood5 wood boiler and a oil boiler as backup.
There is a Honeywell 206625a controller on the oil boiler that controls the flow pump for heating the house via baseboard heat which also regulates the domestic hot water temperature. I also have a Taco SR501-4 switching relay which controls a flow pump which heats my garage via radiant in the slab. This setup was installed for me by a local plumber.

Here's my issue:

The wood boiler does not have a very long burn capacity from what I can tell. It usually will last 4 hours max. I load the wood boiler before going to bed at night and when I get up in the morning it's completely out. I've tried getting up about half way through the night and it's still pretty much out. So anyways, in the morning I get up, the fire is out, and the garage is calling for heat which turns on the flow pump for the radiant heat in the garage slab. This is turned on even though the water temperature is pinned on the cold end of the gauge. So basically if the wood boiler dies down in the middle of the night and then the garage needs heat it starts pumping cold water through the slab and pulling any heat that might be stored in the cement back out of it. I don't like this setup and it doesn't seem right to me. The house flow pump is regulated by the Honeywell 206625A controller to not come on unless the water temperature that it is set at is achieved.

So #1: Is it common for this boiler to have such short burn times?

And #2: What are the possibilities for modifying this system to not allow flow to the garage unless the water temperature is up to temp?

Thank you.

 

[altmartion]

I am a biasi dealer and I absolutely love the support that comes with it. how ever, the wood boilers were a flop in my eyes. we have had so many problems with them I refuse to sell them anymore. yes the average burn time is around 4 hours. I have seen 6-7 but it isn't common. there are a few variables. wood makes the most difference. and I can not count how many simpson controls I have replace because of them sticking opened and shortening burn time. you can get a dual acting aquastat to control a low limit pump.

 

[Rigatoni]

so is the Honeywell 206625A controller I have an example of a dual action aquastat?

 

[altmartion]

so is the Honeywell 206625A controller I have an example of a dual action aquastat?

is that the aquastat? usually the numbers start with L

 

[Rigatoni]

it's on the oil boiler and it has two knobs on it to set two different temperatures.

 

[altmartion]

then yes it is a dual action control. does the low limit side control the pumps?

 

[Rigatoni]

so what you are saying is I need a second controller just like this one?

 

[jebatty]

For a wood boiler burning seasoned wood, burn time is simply a matter of math. Using my Tarm as an example, 140,000 Btuh rating. This does not mean that the boiler continuously puts out 140,000 Btuh, and I reasonably expect about 75% average output over a burn. This also tells me approximate burn time on a load of wood.

Assume 75 lbs of wood in a load. Available btu content of that wood is 75 x 6050 = 454,000 btu's. Average output is 140,000 x 75% = 105,000 Btuh. Burn time = 454,000 / 105,000 = 4 hours and 20 minutes. I couldn't get 6-7 hours burn time no matter what wood is burned. And I would never consider the Tarm deficient or a problem boiler because of this burn time. The Tarm is an excellent performing boiler.

You say you get a 4 hour burn time. Do the math on your boiler, and do the math on any other boiler. That will tell you about what to expect on burn time.

 

[altmartion]

For a wood boiler burning seasoned wood, burn time is simply a matter of math. Using my Tarm as an example, 140,000 Btuh rating. This does not mean that the boiler continuously puts out 140,000 Btuh, and I reasonably expect about 75% average output over a burn. This also tells me approximate burn time on a load of wood.

Assume 75 lbs of wood in a load. Available btu content of that wood is 75 x 6050 = 454,000 btu's. Average output is 140,000 x 75% = 105,000 Btuh. Burn time = 454,000 / 105,000 = 4 hours and 20 minutes. I couldn't get 6-7 hours burn time no matter what wood is burned. And I would never consider the Tarm deficient or a problem boiler because of this burn time. The Tarm is an excellent performing boiler.

You say you get a 4 hour burn time. Do the math on your boiler, and do the math on any other boiler. That will tell you about what to expect on burn time.

I am not saying the biasi is a problem boiler because of burn time. it is an issue but can be fixed. I have spent many day's riding around with mr quince, the owner at qht, diagnosing these boilers. we had problems with sand plugging the hx from the factory, section leaks, multiple control failure, sticking bottom doors and others. I remember smoke being another major issue. burn time is the #1 complaint. if I remember right the original sales brochure stated an 8-10 hour burn. you will never get 140,000 btu's out of a boiler that is rated 140,000 unless it is electric. obviously wood plays a huge factor in burn rate and burn time. plus a few other variables. these boilers when running as advertised are great. a lot of the problem was return water temp. these people were treating this unit like a wood stove. I am very disappointed with these boilers. when they came out I was so exited and pushed them extremely hard and in the end I wound up looking like an idiot. the worst part is it's mostly operator and installation error. I would love to find one cheap so I could tinker with it at home. I think if they ran the damper according to return water temp, these boilers would have been much better.

 

[maple1]

Just a general comment: extending burn times on a boiler comes at the expense of increased creosote production and lost efficiency. They aren't stoves. Best approach is if it just burns wide open for as long as it takes to burn the fuel load and the extra heat over what the loads are needing gets stored for later. Mine burns a load out in four hours.

 

[Orville]

I have been heating with wood in a Buderus boiler for over 30 years and it too has a shout burn time. My boiler has a Honeywell L6006A 1145 aquastat that sits on top of the boiler that controls power to the boilers. If the wood boiler is hot all the controls on the wood side is powered up if the wood boiler cools off the oil side is powered up. So if the wood boiler is not hot enough to produce heat the thermostat is not powered up so it can not call for heat. I have the oil side turned off so when we wake up in the morning the house is down a few degrees and it takes a while to get the house back up to temperature. I would rather not buy the oil so we endure a little discomfort in the morning.

Your garage slab is already in so this is a little late for you, but this is what I did over thirty years ago before in floor heat took off in this country, In my basement bathroom in the area from the bath tub to the door and from the vanity to the wall I dug a hole one foot deep and three by seven foot rectangular. On the bottom of the hole is two inches of Styrofoam. on the sides of the hole is Styrofoam. I put six inches of sand in the hole. This bathroom is the last room of the basement zone to get heat. But after the base board piping radiator the pipe leaving the baseboard makes a loop in the sand so there are two runs of three quarter K copper in the sand. The hole was then filled with sand to the bottom of slab level. The baseboard in that room was never installed, there is just a piece of three quarter copper in it's place.

That bathroom has no exterior house walls it sits towards the center of the house. We leave that bathroom door closed in the day and at night in the heating season. When we go to bed at night the house can be seventy degrees. After the fire dies out in the middle of the night we wake up to sixty- two or four degrees in the house. That bathroom is still seventy or better and the floor is as warm as toast.. For the last couple of days with that door being closed and the rest of the basement maintaining seventy degrees during the day that bathroom is seventy-five right now. I like how the sand stores the heat after the fire dies out and has enough heat in it to keep the room warm until the wood boiler is fired the next morning.

Here is a a picture of my primitive system that I want to re-plumb and tweak the electrical a little.
The second picture is a new picture after I had the sheet metal painted

 

[altmartion]

sand has great heat transfer characteristics until it gets wet. I installed an old buerus wood boiler a year ago. the customer told me he was building a shed around it. well turns out he and I have total different ideas of what a shed is. the front and back of this "shed" are ide opened. this thing runs like crap. and it is all my fault. lol. he wants to sue me but he knows he can't.

 

[maple1]

Orville, if you had room for it, adding a storage tank would improve your situation a lot. If you go to bed with the tank up to temp, your house would still be warm when you woke up in the morning. Depending on size, it might even carry you far enough that you wouldn't have to worry about making a fire on until later in the morning or into the afternoon. Plus you'd reduce creosoting by reducing idling. If you hadn't considered it before, that is.

And welcome.

 

[Orville]

maple 1, I thought about that years ago. I just do not have room for a pressure vessel in the boiler room. I clean the stove pipe and chimney once a month. Right now my controls are shot (zone valves) so the boiler does non run dampered down unless there is too much fire than what is needed to keep the house up to temp.

 

[Orville]

sand has great heat transfer characteristics until it gets wet. I installed an old buderus wood boiler a year ago. the customer told me he was building a shed around it. well turns out he and I have total different ideas of what a shed is. the front and back of this "shed" are wide opened. this thing runs like crap. and it is all my fault. lol. he wants to sue me but he knows he can't.

I feel the Buderus boiler like I have are not made to be outside with a roof and two walls around it. They work well inside. The person I bought this one from sold it because it would not heat his house burning wet wood. He wanted to stay one stick ahead of the fire. With anything cut ahead of the fire he had to knock the snow off it.

 

[altmartion]

I feel the Buderus boiler like I have are not made to be outside with a roof and two walls around it. They work well inside. The person I bought this one from sold it because it would not heat his house burning wet wood. He wanted to stay one stick ahead of the fire. With anything cut ahead of the fire he had to knock the snow off it.

that's what I tried telling him. I didn't think it would work well because it open to the elements. it didn't even have an automatic control for the damper. I had to force him to get one. I offered to buy it but no go.

 

[Orville]

altmartion, Buderus comes with a Sampson firing controller like the one on the front of my boiler. When my controller went kaput a couple of years ago I found it terribly hard to control temperature, as you can imagine. I like my Buderus that is over thirty years old but I need to re-plumb it and change the wiring a little.

 

[Rigatoni]

Here's some pictures so everyone can see what controllers I have on my heating system. Is there any way to rewire this so the second controller won't come on unless the aqua stat on the oil boiler comes on? Or do I need a different controller to do this? If so, which one should I get?

Awoke again this morning to the wood boiler out and the garage pumping cold water through the slab.