Post 1 - Unusually Cold and Not Keeping Up

[Gooserider]

Before going out to purchase pallets, make the rounds of all your local businesses, especially places that use heavy stuff, or do manufacturing / assembly, and ask them about the availability of old pallets - many times these are throw-away items, that the place would have to pay disposal fees on - and they will be delighted to have someone take them off their hands... But ALWAYS ask, as some places re-use them and will get seriously upset if you take ones you shouldn't.... This also gets to be a bit hit or miss in the winter, as you will be competing with other wood burners for this resource (Usually it is easy to get a huge supply in the summer)

I've had good luck at my local getting pallets at my local tile and rug place, and I've heard paint stores can also be good...

Because pallet wood tends to be very dry, it will go up very fast and hot, so it is best not to use a lot of it by itself - mix it with other greener wood to slow it down a bit - this is where the moisture meter can come in handy, as it will let you try to get something close to a reasonable "average MC" for the entire load...

In terms of the nails, don't know about the BioMax, but it has been discussed here in regards to other gasser brands, with the conclusion that they aren't a problem, and that judging by the ash area contents, the peak fire temps are borderline on the melting point for pallet nails...

Gooserider

 

[rwh442]

Tennman,

I'll be the fifth or so person to comment that your 10 degree loss from the boiler to HX is HUGE. I am pumping 240' one way, 1" pex and lose around 1.5 degrees at max 185 degree output. So you're dumping 20 degrees MINIMUM in the entire loop. You need that return temperature measurment at the boiler. I would almost bet that you have a bad temperature gauge/sensor somewhere.

 

[Mike T]

Nails won't be a problem with the biomax.

 

[Tennman]

All good news regarding the how to get thru the season with the wood I have. But, the comments on my energy loss between the boiler and the HX is depressing. I will be looking at this more closely and I now know I don't have near enough temp gages to really debug the system. So many of my decisions were based on thinking this beast will be such a big honking heat machine in our temperate climate I'm not gonna sweat the small stuff..... Then a week of this Global Warming hits Tennessee!!

I may have to dig up my PEX lines and redo the most miserable part of the job. At least the yard's still a mess. Like some feedback from other folks with 1.25" PEX, but the 1*/100' of run seems to be the rule of thumb. Looks like I'm off by about a factor of 5 (~180' one way).

My wife and son helped with the PEX insulation. Not looking forward to that conversation if we need to yank it out. Sigh....

 

[gorbull]

"My wife and son helped with the PEX insulation. Not looking forward to that conversation if we need to yank it out. Sigh...."

My god I feel for you brother! Best thing is to pack them off to Hawaii for a week and go at it. Know one needs to know nothing about what's burried in the yard!

 

[Tennman]

Yep.... good idea. And when they ask about 180' of fresh dirt I'm gonna say just tilled the soil for the grass seed!! Kinda like Vegas.... What's said on Hearth.com stays on Hearth.com.

I've got another point for the RULES for BOILER NEWBIES.... Don't go cheap on the ugliest part of the whole job. We'll see. More measurements before I decide I'm warming China.

 

[rwh442]

I remember almost EVERY MINUTE of that dreaded "bury the insuated PEX day". What a PITA. A couple of days after that I came down with THE WORST sinus infection I ever had in my life. Lasted for weeks. I feel for you if you have to dig that up again. Good luck.

 

[sdrobertson]

I've got another point for the RULES for BOILER NEWBIES.... Don't go cheap on the ugliest part of the whole job.

I'll be replacing my lines this summer as when I installed I was using a OWB and didn't want to spend the few dollars on O2 barrier pex and I went with 3/4" as that's what everyone else did at that time around here.

 

[Gooserider]

Seems to me like before you start firing up the shovel team, it might be worth a couple things...

1. Describe what you have for buried lines currently - is it a commercial product like Thermopex, or some kind of "home-brew" approach - if so, what did you do? How did you bury it - i.e. how deep, and did you put much sand and gravel around it, or is it just in the dirt?

2. Get some really good instrumentation on the lines, confirm that you really DO have a problem, not just some bad thermometers... - Ideally I would look for a digital logging setup that would let you monitor all the temp readings at once so as to get rid of the time variable, and I would also do some kind of "calibration check" to make sure that the sensors all read the same - i.e. put them all side by side in a pot of water, or the oven and run the temp up and down. It is less important what the exact degree reading is, than that they all read the same, since what we are looking for is the difference in the readings.

I would then attach one to each point where the PEX goes into / comes out of the ground - using as consistent a mounting method as possible - i.e. fasten the sensor snugly to the tube and wrap it with a good layer of pipe insulation...

Gooserider

 

[Tennman]

An update after all the kindly advice. Took off the door to clean the ash in the bottom lower chamber. Good bit of ash but not enough to block the flow. Boiler was gassing and I was astonished that nothing was very hot. I carefully placed my hand into the chamber and the flow coming from the lower chamber was not very hot. Hopefully that means that the boiler is doing a good job in heat transfer. Took the draft fan of the back of the boiler and the blades had a slight coating of crud, not bad, but cleaned them because it was off. There was not much creosote on the exhaust path to the flue. Given what I'm burning this season I was expecting worse. Never paid any attention to the path of the lower chamber gas path. It comes out of the nozzle, travels forward, then along the side passing fins to help conduct the heat into the sidewall. So here I had some ash on these critical heat transfer parts I never bothered to pay attention to previously.

Wanted to give some status for the educational benefit of those who provided some advice. I've learned a bunch in the last few days. Will be doing some better data collection on the underground PEX situation. If the results are bad I'll tell you how I screwed up so hopefully others won't repeat my mistake. BUT the verdict is still out (fingers presently crossed) on the underground PEX situation.

 

[Gooserider]

I don't know - most of the gassers don't have much heat transfer until the jet comes down into that lower chamber - judging by NoFo's experience w/ his thermocouples, I'd have expected that if you stuck your hand into the lower chamber when the unit was gasifying, that you'd be pulling out blackened stumps. My one encounter with a live gasser was that it was uncomfortably hot 3-4 feet from the door, I'm not sure I COULD have stuck my hand in there...

Are you sure that you have your air mixes set up properly? What color was the flame? Were you burning that not-so-dry wood when you did this?

Gooserider

 

[Tennman]

Goose, to clarify the BioMass has ash cleanout acess panels in the very lower back chamber of the boiler. This is an ash cleanout prior to exhaust gas rising up the back, thru the draft fan and into the flue. That chamber is AFTER the hot gasses of the lower (secondary) chamber circulate and exit heading to the flue. I was expecting more heat in this area, but it just being warm is hopefully an indication of good heat transfer to the boiler. No, I didn't stick my hand into the lower chamber where the nozzle is. Temps are warming up here to more normal which will give me time to debug my issues and keep the house warm. Prior to starting this thread I was pretty ignorant of all the functions of the boiler. This is forcing me to understand all the working elements of the BioMass. This whole process is nothing like punching the button of a heat pump and walking away. Its like owning a horse, whether you like it or not you're gonna get to know the beast if your gonna ride it.

 

[Tennman]

This is a thank you reply to all of you who provided the great suggestions a few weeks ago to this post when I was struggling.

Two key changes transformed my system and both had to do with my knowledge, not a weakness of the system.

1 - Lead dog and others suggested I up my pump on temp. I had it running with the factory setting of 144F. I also have the 140F thermostat in my Danfoss. By changing my pump on temp to 160 immediately I saw system temps rising and heat to the house improving. This helped because of change 2.

2 - My TOTAL misunderstanding of the function/flow of the Danfoss valve. And this is REALLY BIG for newbies. I'd been operating my system for 2 months with the throttle valve upstream of the Danfoss WIDE OPEN thinking that the thermostat was automatically throttling flow for the mixing. Taxi (Rob) asked about tuning this valve and I also spoke with Zenon, THEN when all else fails.... I read the Danfoss instructions and looked at its design. Good Grief, for two months a small fraction of my available gpm has been going to the house. No wonder the house was cold! These two changes got the whole system up to happy temps. With the boiler now staying in the 170-180 range it became far less sensitive to my poorly seasoned wood. The return temps from the house and HX temps are far more inline with all that you guys were telling me. I'm still concerned long term about my PEX insulation process, but that was clearly not a major factor. The majority of the system gpm was taking the path of least resistance and that was thru the wide open Danfoss return to the boiler. If I had to guess I would imagine between 20-30% of the thermal energy coming out of my boiler was making it to the house. I'm still a little confused why the system wasn't getting to temp within that short circuit but frankly I don't care now that its getting hot.

Thanks guys, I'm certain another newbie DIYer will be describing my situation and you guys can ask him if he's throttled his Danfoss down and increased his PUMP ON temp. Good thing I'm still having fun, this whole process is not for the casual observer.

 

[deerhntr]

I was kinda betting on the underground pex. BTW, can you give an update on how you did your UG pex install, and what you found there when you went back in search of your problem?

 

[taxidermist]

Glad you got your system running better. I too had the same problem last year when leaddog talked me down off the ledge. I was running a cold system for about an hour. I was working in the barn watching for leaks and other problems when my boiler went into idle. I said to myself man I know I bought a bigger boiler than I need but damm that think heated up 1040 gal of water fast. I went into the house looked at storage temp and it said 120 at the top.......oh no what did I do???? After talking with Les he told be the ball valve on the boiler protection loop would be my friend and that I needed to close that down. I did and the boiler ran like a charm. I still mess with it every fire.


Rob