Post 1 - Unusually Cold and Not Keeping Up

[Tennman]

What a test for our new boiler. Just to get everyone on the same page I'm running a BioMass 60. Been up for 2 months. I'm having so many issues I'm about to go out and purchase some seasoned wood so I can get a working baseline. I'm currently running propane and the boiler to keep the house warm during this very unusual cold snap. I'm getting good blue flame, but its like the transfer tubes are insulated. But that could be because of the non-seasoned wood. I feel like I'm back in Math classes where I have more variables (unknowns) than I have equations... a problem can't be solved if you have more unknowns than equations. I've been giving a bunch of thought to a wood boiler "dyno" so I can figger out what the heck is going on, i.e. temp probes and oxygen sensors, etc. I've discovered that you can't have too many temp gages in the system. Not too frustrated yet because I know I haven't begun to establish a good operating baseline.

 

[Singed Eyebrows]

I know with my Atmos the factory says that it doesn't even run as a gassification boiler with high moisture wood. It's kind of a shock that you can't keep up with that big boiler where you are. What is your flue gas temp? Do you have a loading unit on it? Laddomat or Termovar? You should get the heavy hitters chiming in soon. My knowlege is very limited, Randy

 

[Tennman]

Yeah, that's the kind of information I need. Just recently read here about guys monitoring flue temps. I'm gonna check into getting one of those. But it has been in the teens here for days. That's very unusual for us. Had to deal with some frozen pipes this morning. My first time that's happened. I see a blue flame, but the water temp just ain't there. I have a Danfoss mixing valve with a Taco 0013 in the loop. I'm pretty confident in the piping. I've got a long run (180') but when on temp (180F) I'm seeing about 8-10F loss into the HE. That seem about average. I think I need more sensors just not sure what will work with all the ash, creosote etc. thanks.... stay tuned I'm sure some of these guys will pitch in.

 

[stee6043]

What is "unusually cold" for you? You have a pretty big boiler. Give us some details of your setup. Even with less than prime wood you should be able to do "okay" for most outside temps. A properly sized boiler should not be outrun by super low temperatures. They should be sized for worst case from the get-go...you're in the right place to get some tips....

 

[stee6043]

Yeah, that's the kind of information I need. Just recently read here about guys monitoring flue temps. I'm gonna check into getting one of those. But it has been in the teens here for days. That's very unusual for us. Had to deal with some frozen pipes this morning. My first time that's happened. I see a blue flame, but the water temp just ain't there. I have a Danfoss mixing valve with a Taco 0013 in the loop. I'm pretty confident in the piping. I've got a long run (180') but when on temp (180F) I'm seeing about 8-10F loss into the HE. That seem about average. I think I need more sensors just not sure what will work with all the ash, creosote etc. thanks.... stay tuned I'm sure some of these guys will pitch in.

8-10 degrees loss over your heat exchanger is a bit on the light side. Most folks push for closer to 20 for max efficiency. That is one big pump you're running. What size thermopex? What kind of heat exchanger do you have? If you're getting 180 degrees on supply side where is it you're not seeing heat? Or is the 180 just not lasting? Are you measuring supply and return at the boiler or just in the house?

For what it's worth most of us run cheapo external flue temp gauges. They work great on single wall pipe if you have some exposed....

 

[webie]

Blue flame doesn't sound right , If you are or have been burning green or wet wood , you could have insulated your transfer tubes with a coating of creosote and ash .
I would suggest a toatal cleaning and get some dry wood and then try it .
This boiler should be enough to heat a small mansion .

 

[Mike T]

I have a problem with my system- but its not the boiler.
My Biomax had a problem with heat not getting out to the system. I believe its due to the pipe return run getting too cold.
This closes the thermostat and the boiler system only uses the loop between the boiler supply and the mixing line return.
The mixing line return does not have a feed from the return system system to mix the water- it only comes from the supply.
This bypasses the thermostat and goes to the upper feed on your Danfoss.

So having said that- is your temperature at the plate hot enought to transfer heat of are you stuck in a loop like me?
The bioler temperature will read great but there is no heat where it counts.

PS- I temporarily took out the thermostat and it runs fine until the plumber comes again. We need to put in a line to supply water from the return into this pipe to actually mix this water and cause hot water to go into the rest of the system.

 

[Duetech]

What a test for our new boiler. Just to get everyone on the same page I'm running a BioMass 60. Been up for 2 months. I'm having so many issues I'm about to go out and purchase some seasoned wood so I can get a working baseline. I'm currently running propane and the boiler to keep the house warm during this very unusual cold snap. I'm getting good blue flame, but its like the transfer tubes are insulated. But that could be because of the non-seasoned wood. I feel like I'm back in Math classes where I have more variables (unknowns) than I have equations... a problem can't be solved if you have more unknowns than equations. I've been giving a bunch of thought to a wood boiler "dyno" so I can figger out what the heck is going on, i.e. temp probes and oxygen sensors, etc. I've discovered that you can't have too many temp gages in the system. Not too frustrated yet because I know I haven't begun to establish a good operating baseline.

To get a working baseline that you know is not "ill seasoned wood" buy a couple 10# of bags of charcoal and burn it instead of "supposedly seasoned" wood. Guaranteed seasoned wood is really difficult to locate this time of year as most sellers are thinking OWB not moisture content.

Do the regular kindling build up but put the charcoal instead of wood on to burn. If you get gasification and thermal output you will know you are on the right track.

 

[in hot water]

If you know the temperature leaving the boiler, and the temperature returning, and the flow rate in GPM then you know what the boiler is putting out.

Output with water as the transfer fluid Output= 500 X flowrate gpm ( Δ T)

So 10 gpm of flow with 180 supply-172 return= 40,000 BTU/hr.

Try 10 gpm with a 20 degree Δ T 500 X 10 X 20= 100,000 BTU/hr.

You need to determine the actual flow rate either with a flowmeter in the circuit or the pressure drop across the pump. A pressure gauge on either side of the pump gives you the psi difference. Then use the pump curve for that circulator read the pressure drop across to the flow to see what the pump is actually doing in your system.

The output of the coil in the duct is a bit more involved to calculate. You need to know the entering water temperature, flow rate through the coil, entering air temperature, and air flow rate through the coil. The manufacture of the coil will have the output curve to indicate coil output based on those numbers.

Either the boiler is not transfering the BTUs, the distribution piping is constipated, or the coil is undersized. Or a combo of those.

Fluid could be blocked by a plugged strainer, piping or pump undersized, airflow blocked through the coil or wrong fan speed.

Regardless you need some gauges and data to calculate where the shortfall is.

Better wood will not help if the system cannot move the energy and distribute it.

Does the boiler come up to temperature and ramp back? This is a simple way to determine if the boiler is not producing or moving the energy.


hr

 

[Tennman]

Excellent.... House is 4800sqft very old poorly insulated including many original 150 yr old windows. Boiler is about 180' one way from boiler house to heat exchanger in the root cellar. I put in 1.25 PEX. The Taco pump was sized based on the Taco TD10 Sizing Datasheet which I used to estimate my head losses based on the tables and my guesses for elbows etc. The head losses and amount of BTUs/hr I needed to pump said the Taco 0013. Installed a 170kBTU heat exchanger in the existing duct work to use the 2000 cfm furnace fan in place. The 8-10 degrees delta T was the temp drop from the boiler to the HE inlet (not real bad insulation on PEX is it?). At the moment I don't have a temp out of the HE because I thot the boiler would create more energy than the 105Kbtu furnace fan could cool. So it looks like I need more temp sensors to diagnose. I was thinking of calculating BTUs into the heat exchanger since the pump gpm is known (sorta) and I know water temp that would give me a rough idea of boiler output.

We are only heating the downstairs and accepting whatever the upstairs sleeping rooms end up. The boiler is using the ductwork for the downstairs.

Here's a key, the system works great when I can deliver 165-170F water to the HE. The boiler is really struggling to get to 160. the suggestion that my tubes are creosoted makes sense. I was thinking that although I have creosote in the upper chamber, the sides of the lower chamber is only a grey ash. no indication of creosote in the lower chamber. Thanks for all inputs. Not sure what I'd do without this site.

 

[webie]

Here's a key, the system works great when I can deliver 165-170F water to the HE. The boiler is really struggling to get to 160. the suggestion that my tubes are creosoted makes sense. I was thinking that although I have creosote in the upper chamber, the sides of the lower chamber is only a grey ash. no indication of creosote in the lower chamber. Thanks for all inputs. Not sure what I'd do without this site.[/quote]
Is the boiler running continually and not making enough hot water or is it cycling ?

 

[webie]

thermometer do you have cooking meat thermometer and a little duck tape , that will work on the exit hx and give you an idea where you are at .

 

[leaddog]

The 8-10 degrees delta T was the temp drop from the boiler to the HE inlet (not real bad insulation on PEX is it?). Here's a key, the system works great when I can deliver 165-170F water to the HE. The boiler is really struggling to get to 160. the suggestion that my tubes are creosoted makes sense. I was thinking that although I have creosote in the upper chamber, the sides of the lower chamber is only a grey ash. no indication of creosote in the lower chamber. Thanks for all inputs. Not sure what I'd do without this site.

10* drop from the boiler to the hx is HUGE. I don't know what the gpm being delivered is but you are heatting the ground or something else. Alot of btu's are not even getting to where you need. to get 170 water at the hx you need 180* leaving the boiler.
What kind of insulation do you have on your piping?
What is the temp of the boiler water leaving the boiler? also what is the temp returning. If the returning water is to low you will have a hard time having much flow at 180* at peak usage. It takes some time to raise the temp.
Is your boiler ever idleing or is it running full out?
leaddog

 

[leaddog]

another thing. What do you have for cold water protecting? You can try and set the setting for water leaving the boiler up to 170* or so.
On my eko80 I have my pump not come on untill 170* and have my 3-way valve not send any water to the house untill it reaches 185*. It really cooks at that setting. even then the 3-way valve cycles alot if the return water temp is low. I can watch the water temp raise about a degree to 3* a minute when it is just recycleing and it holds 80gals of water but when the water temp of the boiler is lower like 160* it is alot slower.
leaddog

 

[ihookem]

You need to insulate your house better with the temps you are getting. Insulate the attic to r 38 or so. Tap on the windows and if they rattle there is air leaking through so reglaze or use a small bead of caulk. Check weatherstripping under the doors too. If you see anyplace air might be leaking it's time to foam the cracks shut. Attic insulation is most important though. When it's cold like "up north" it is imperative to find any air leaks and shut them with foam or caulk. It was 12* in Paris Tennessee the other day. When it's 12* here I use quite a bit of wood. My house is a 2200 Sq.ft. ranch and is insulated with r 60 or r 65 in the attic. The walls have r 28 of foam and Anderson double pane glass with storms on and has brick on the outside. You can run your Biomax full blast and might not keep up with that size house without insulation. I think I found your missing variable. If you insulate the attic you will notice a big difference one hour after you are done. You will burn less wood and You will notice cooler temps in the summer too. Later, ihookem.

 

[flyingcow]

10 degree drop from boiler to HX is big, really should be 1 degree at most. Which you probably have a big drop from house to boiler on return side. AND this will get worse as time goes on. Doubt if this is your problem, but you got a project for next summer.

 

[laynes69]

If your home is that old like ours it may be a balloon frame home. If thats the case, you may have open cavities into the attic that run through the house. Our walls are full of foam, and we have good windows, but we had some serious heat loss. I went into the attic and I had 25 open cavities that were letting heat out of the home. If your attic isn't insulated, I would air seal then insulate. All said and done, I sealed the equilivent of a 5' x 5' hole in the attic letting heat out. I still need more insulation in the attic, but the air sealing alone has made a huge difference on how the house heats and the comfort level.

 

[Tennman]

Ahhh.... So much here to digest. I'll work my way down.

1) Our attic is pretty well insulated but the window and doors are full of leaks. My first goal here was to take a big bite out of the propane bill then focus on the house's efficiency. I've got lots of free wood but its not very good for this season.
2) From what I've read here I didn't think 10* was too bad between the boiler and the HX given how long the run was. Our ground doesn't get nearly as cold but if that's considered bad to you northern guys I better look at that. I will take a better look at it when I get it up to temp. Hopefully I'm wrong and its not that bad. So going 180' one way at say 175 you're getting better than 165 at the HX?
3) the boiler is working continually and we're always stirring the wood to prevent bridging and not sure what you call it but blowing holes around the nozzle. We are splitting smaller splits now to help with the bridging.

Wow.... so much to do right here.

4) The bags of charcoal is a great idea!! will do that.
5) NOW.... I have my pump turn on temp to 145*. It really acts like between the house load the the temp loss to the long lines I'm losing lots of energy. So the suggestion to raise the pump on temp really could make a difference. I was expecting with this boiler's capacity that I'd have a hard time dumping all the heat.
6) I have the Danfoss with the 145* thermostat in. I did an experiement about 2 hrs ago and closed off the lines to the house and the temp started to build in the boiler. It really acts like between not producing many BTUs due to wood and temp loss in lines.

I'm going out to adjust the pump on temp. Still don't think I'm getting the heat. Will plan to get some pressure data to get gpm. good suggestion. You guys have now given me a week of debugging tasks. I like the lowering of the pump temp but I think my boiler should be able to stay ahead of the capacity of our 105kbtu propane furnace and the 2000 cfm blower. The energy calc is really what I need to be able to do. that's what I was kidding about the boiler dyno. Will use those calcs IHW.

ihookem you wouldn't be a longhorn also would you? thanks webie, leaddog, and cave. forgive me if I forgot someone. I am also getting PM's from BioMass guys on vent settings which I haven't touched.

 

[sdrobertson]

3) the boiler is working continually and we're always stirring the wood to prevent bridging and not sure what you call it but blowing holes around the nozzle. We are splitting smaller splits now to help with the bridging.


4) The bags of charcoal is a great idea!! will do that.

Before you start messing with all of the primary and secondary settings, use the bag of charcoal. With the "holes around the nozzle" and having to stir all the time, I'd wager allot that the wood is the biggest problem. I've burnt wood for a long time and what I thought was dried wasn't even close. I went through this when I started the thread "fine tuning a EKO" and all the fine tuning helped allittle but it really came down to the wood dryness. I'm a little slow at catching on even though everyone was telling me that it was my wood dryness, it still took awhile to listen to them. For this year your unfortantaly going to have to deal with the wood condition and split the splits small and keep stirring it up. I used the charcoal trick last year and it really helped get a good coal base which helps with wetter wood. It'll be a pain this year, but if you get ahead in your wood supply, next year will be a pure pleasure burning the boiler.

 

[Tennman]

SD. That tuning post is huge. I spent New Years day morning with it. I think 80-90% of my problem is the wood. I'm burning mostly oak and hickory I split about a month ago. These were downed trees but when we split it I was amazed how wet the splits were. Clearly I can't expect much drying to happen in December and January. I'm sure my settings are off, but if my moisture content is very high that would explain it all. I'm keeping wood in the upper chamber attempting to dry it so that by the time it gets close to the coals hopefully it will be good. Now I'm worried about the quality of the insulation on my PEX. That was a miserable job. I'm learning I need lots of more temp gages. thanks

 

[Duetech]

Tennman, My pex run is 100' round trip with 1/2-1* loss with 1" pex. You have the better size pex for your needs unless you went to 1 1/2". Not trying to get you to down size. Just showing thermal loss. Ideally you shouldn't be losing more than 1* per hundred feet.

 

[Tennman]

Changed the pump on temp last nite and that change was huge. It appears that between house demands and pipe losses the poorly seasoned wood the boiler was couldn't keep up. By resetting the pump on temp to 160* the boiler is running hotter and this is helping it overcome the unseasoned wood. My Danfoss has a 140* thermostat, my controller pump on setting was 144* with a 4* hysteresis (deadband). So since it was always "behind the power curve" it wasn't doing well with the wood. I just reset the pump on temp to 165* since, as I've read here before, these things really like it hot. I will still do all the other suggestions but given our current heating demands the boiler apparently couldn't keep up with the quality of wood I'm presently using and the system losses. I'm really concerned about the line losses. Installing the PEX was the most miserable part of this whole project.

Thanks guys... All great suggestions and all relevent.

 

[Tony H]

With all the info in this post it gives you alot to consider but it probably comes down to the wood not being dry enough to get good gasification going.
First do the charcoal test this will help confirm whats happening. Assuming the wood is the problem see if you can get some dry wood from a friend or tree service.
You can try mixing dry and not so dry wood you will need to open up your air supply and increase your fan setting to get as hot a fire as possible.
When you fire up the boiler also turn the furnace on and get the house up to temp then after the boiler is hot let it take over and even with the reduced output the boiler might be able to keep the house warm. You might have to do this each time you reload the boiler but then the 6-8 hours between reloads the boiler might be able to keep the temp up.
BTW I have used this 'trick" to get by when I have had to use marginal wood

List out all the other suggestions and start to go over them to develop a plan to upgrade and improve the other items that need attention.
The boiler you have should be fine when you have nice dry wood to use next year.

 

[huffdawg]

Maybe hang some wet wood up high in your boiler room to dry in the meantime

 

[willworkforwood]

I’m burning mostly oak and hickory I split about a month ago. These were downed trees but when we split it I was amazed how wet the splits were.

Tennman, I do a lot of oak, and I'm guessing you're burning 30-35% wood - you should get a MM to find out how bad the news really is. Another idea along the lines of charcoal: you can try to find a dealer or large user of oak pallets. These are usually KD and have very low MC. The price of used, broken ones is usually fairly reasonable. If you put a layer or 2 of pallets in first, you can help things out. But you would need to find out first if the nails in the pallets can cause any issues for your BioMass (dropping into nozzle ports, etc). But, another thing you need to consider when burning unseasoned wood is creosote deposits on the heat tubes. Last year I tried to "get away" with finishing the Spring with poorly seasoned wood. I was checking everything visible for creosote, including the chimney, and nothing appered to be wrong. But, when I started the annual boiler cleaning, there was a big, nasty creosote surprise in the heat tubes, which resulted in a nightmarish cleanup job :sick: . I don't know how your BioMass is constructed, but if you can get a look at the tubes without a lot of work, you should do that ASAP. Good luck - next year will be better!