Hey everyone - happy Thanksgiving,
It's been a fun month or so getting to know the new boiler. For you guys with automated units, I'm just curious what kind of secondary settings you see?
I had a fire this morning and the secondary was at 62% and it flirted briefly with 63%. The rumbling noise was quite impressive. It's kind of become a point of interest of mine to see how wide open that secondary will ever get. So, just curious what others have seen and what I can set my sights on.
This thread should go back on track.
I have the same boiler, the Froling FHG-L 20,. First burn was ~ 7 weeks ago at the end of October.
The thread should really sell a few more Frolings, though I have to be careful what I say.
I am set up for HW storage with taps and valves ready in the primary header, but I'm a bit non standard right now and using the 1200 sf, 4", radiant basement slab for storage. I knew this was not enough load for the full burn and was concerned, depending on the Froling's ability to turn down the output. Briefly, I am getting perfect burns with no slumbering and huge turndown. I am injecting 135 deg F and returning 100 to 110 F from the slab at the balance point.
Initially with the factory defaults I did not have enough load and saw some slumbering in the first few days with trial small loads. I considered my options and five minutes of googling delivered the factory code to enter the service menu and have access to changing operating setpoints. No hardware modifying. All I had to do was lower the minimum flue gas temp to 95 deg C (because the slab is not enough minimum load) lower the supply water temp to 73 deg C ( the Froling is slow to modulate above setpoint, it operates substantially higher, usually 80 to 90 C HWS, at minimum load), and raise the slumbering temp to max (20 C above HWS setpoint or 93 C).
Typical burn, I can not load more than halfway. At the end of the burn with only the warm slab for load, it runs 20% primary air, 10% secondary air, 35% draft fan speed, 16% excess oxygen, but it is drafting through the charcoal bed and flue gas is 110 C which is to much for my load, and the HWS temp runs 90 C. Flue gas temp ~ 100 C will get me 80 C HWS temp. The Froling at that point is running on the (programmable) minimum draft fan speed, 35%, minimum primary air at 20%, and well above HWS and flue gas setpoints. Half load burn time is ~ 3 hours.
DHW load plus the basement slab is enough load for the Froling and will pull down the HWS temp to above setpoint at the minimum burn rate.
The Froling is a lot bigger than the Weil McLain 3 section Gold oil. The basement slab load burns the oil.
Although I am sold on storage, it's in the future. I am getting everything I want right now. Unlimited heat and DHW and its very light on fuel. I am burning two 32 gallon Rubbermaid barrels of wood in ~ 3.5 days. About equal to a full 6 cu ft wheelbarrow load for three days. I have three years of cordwood in the yard and am burning the junk first.
I wanted initially quick heat with minimum fuel. Circs start up after ~ 15 minutes and 1 hour later the DHW load drops out and the slab is returning 100 deg F. It goes quickly to minimum load and ~ ten minutes later the Froling has turned down to 35% draft fan speed and 20% primary air. The secondary air always runs at the minimum setpoint of 10% and above minimum excess O2 ~ 12 to 16%. I've seen 50% secondary air only if I open the boiler and poke the coal bed at minimum load.
Payback is ~ 5 years with nice heat.
The Froling is effortless to light, mostly put the wood and paper in, light and walk away. Three minutes. I am burning birch and swamp maple from outside. I am loaded with red and white oak after I burn the junk.
