Bohart Guest House
Renewable Energy System
AgSolutions
Boiler, Equipped with the Kagi Burner
200k btu model, installed Feb 2006
First of all, the Tarm wood-fired boiler needed far too much attention and was removed after a year. There is a lot of debate in the eastern US about emissions from wood-fired boilers and I agree they are smoky. Once they are up to optimal burn temperature there is no visible smoke coming from the stack, but getting them up to temperature proved to be very tricky and smoky. They are supposed to turn off and on automatically and cleanly, but as the smothered fire is fed air it spews smoke until the flame catches then continues to smoke for another 2-5 minutes until it comes up to temperature. I saw it create an entire bank of fog over my corner of town, no exageration.
My review of the AgSolutions Boiler equipped with the Kagi Burner: The burner is great, the company selling the boiler (which includes the burner) is problematic. Even though AgSolutions promises that this unit is sold 'vegetable oil ready' it is far from true. Even after asking AgSolutions the question in multiple formats, I was assured that I would have no problems running the unit in an unheated garage in Montana. I turned out to be a guinea pig. The owner of the company, Anthony in Kentucy, will not respond even to constructive criticism and chooses to just keep selling units complete with false promises and creating work for his service men. The man in charge of the northwest is great but even with his endless support I have spent over 500 hours hovering over this unit in the last 36 months. At this point, Jan 2009, the unit is still operating sporadically and requires constant attention to verify it is still operating.
I will say that the burner manufacturer, Kagi Waste Oil Boilers in Spokane, is quick with advice and service, and is fully revealing of the challenges presented by burning vegoil in their burner. They have a burner occasionally in use on vegoil in their heated shop and it works great. See below for what is needed to run this burner on straight vegetable oil. If you go into this KNOWING that you need to make some modifications to the burner then you'll be far better off. For me, the hard thing to swallow was being promised it was ready to run on vegoil, then finding out in the first cold snap (when you are needing a lot of heat) that it needs modifications. I burned a lot of natural gas in my backup boiler while I was working to modify the burner. Had I known what was required to use vegoil, I would have done it from the beginning and saved a lot of maintenance and headaches.
The main problem areas are:
Fuel heating:
The burner's fuel lines and fuel pump are not heated, which is a
task not easily accomplished due to the odd shape of the fuel pump and the tight
space surrounding it. The burner manufacturer in Spokane has some
prototype fuel pump
heaters (custom cup-shaped aluminum blocks with water channels that hug the
pump and fuel regulator) and they will sell them. I tried heat tape but the type I used did
not solve the problem (most
heat tape is self-regulating and stops heating when in contact with warmth).
So the addition of hot water heat is the only way to keep the fuel flowing, as
the pump must be 130-140F to prevent coagulation of animal fats and hydrogenated
oils which are almost always present in used cooking oil. The copper fuel
line from the pump to the fuel regulator must also be heated.
The aluminum heat block inside the burner uses about 300
watts of electricity and is thermostatically controlled to achieve a 170F block
temperature (adjustable to lower temps for other fuels), so I added hot water heat fin tube below the burner and
built a foam cap for the whole front of the boiler. There is a burner
manufacturer out there that uses hot water heat to do the job, but I stumbled
onto them after I purchased my boiler. It is called King Built.
Dirty Burn Chamber:
After 3 years of operation, the burn chamber is coated with hard carbon build up deposits so thick that it takes a hammer and chisel to carefully remove, and that's the easy part. The heat exchange tubes are 2" in inside diameter and about 2 feet long, and I am at a loss on how to clean them. Of course, the efficiency of the boiler is compromised by having the buildup insulate the water from the hot gasses. There is a stiff 2" brush sold at plumbing supply houses, and that works to remove dusty buildup, but no brush is going to take this scale deposit off. I tried attaching the brush to an electric drill and it had no impact on the deposit buildup. AgSolutions chooses not to provide a $3 brush and in fact the brush is not mentioned in their manual of operating and maintenance instructions.
Air Compressor:
Only general recommendations for air compressors were given, and
no information about how to avoid or mitigate water condensation problems.
The burner uses compressed air to pull fuel from the nozzle to create the
flame, and the air compressor is not sold with the unit; it must be purchased
separately. I started out with what I had, a Costco/Coleman compressor
which was noisy and used a lot of electricity. After much review I
purchased a small Makita 700 and added a second air tank to increase cycle time.
It is very quiet and efficient but is showing signs of getting tired already.
After getting the right compressor, the problem of
condensation was tackled by locating the unit between the boiler and the
boiler's fuel tank, a 275-gal pallet tank, both good sources of waste heat.
The compressor area was then insulated but condensation continues to build up so
I drain the tank weekly to keep the air lines from freezing up or water from building up in the tank.
Insulation:
The boiler is shipped with the sheet metal off, and some yellow
insulation is supplied to be installed between the barrel and the sheet metal,
but they don't give you nearly enough.
Information:
There are quite a few handy tools you will need to work on this
baby, but they aren't listed in the manuals. To clean the boiler
heat tubes, a hard to find 2" wire brush is needed, but AgSolutions is resistant to
supplying that $3 item. There is no maintenance schedule, so you'll figure
out why the boiler is not working after it goes down, and you may or may not
replace the correct items first. Usually it is the O-rings, $.20 items
that are also not supplied or listed by size so you have to order them from Kagi
or take the nozzle to
the hardware store and try to determine what size it was before it wore out.
There is also a $1 fuel pump cup gasket that they don't include spares of, and
you have to get that from Kagi or your service rep. I wore mine out from
removing the fuel cup too many times to clean out the thickened oils, and was
instructed by AgSolutions to use silicon to make a gasket, then spent the next month cleaning
dried silicon goobers out of the flame cone and small oil channels in the heat
block. To do that I found out you need an automotive O2 sensor removal socket
and an impact driver, then I got oil inside the electronics box which is
unavoidable and the oil got up into the circuit board and fried that up so the
boiler sat cold for 4 days during a below zero weather cycle so the natural gas
boiler had to take over and waste a bunch of fossil fuel.
That's about how it goes until you've practically
disassembled the entire thing and don't have to call your service rep anymore
because you ARE a service rep by then. Again, if you equip the burner to
run in cold temps then you'll do far FAR less maintenance, and maintenance is
what wears out the gaskets and O-rings.
I may have overcome most of the challenges but beware that you should ask for the cold climate retrofit. All attempts on my part of offering to help AgSolutions create such a kit and a special section to the owners manual have gone unanswered, while Kagi is much more responsive. So while I believe in the basic quality of the equipment it should be known that it is up to you and the service representative to make it work. It's certainly not rocket science but almost all of this hassle is avoidable and it's frustrating that the company which collected your $6000 doesn't care to avoid the hassle. It certainly costs them to deal with you when you've got them on the phone everyday so go figure. Some people like to stay behind the wave and then wonder why life is hard. I would highly recommend getting your service directly from Kagi, which is great.
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