koker blower limits question

koker 160 model. my stepdads brother suggest i set the blower limits to 115 and 90. he says this will "use less coal". ive done so since mid oct and it does fine but is what he says true? is there a more efficient or economical setting for the blower moter? im baffled by this topic. the factory high limit of 200 deg hasnt been touched. thanks.

The factory settings are 160 deg blower on and 120 deg blower off. Changing the settings to 115 on and 90 off means your blower comes on sooner and stays on longer, blowing cooler air much of the time. I don't see how this would save any coal though. You just run your blower longer.

thanks Len. i hate to mess with something thats running well but i didnt give the factory settings a try either, so maybe ill mess with it. i did, however, set the white feed knob down to 6 turns as opposed to 8 or 9 as factory was. i do feel that with the blower running longer im getting a more constant heat as its pushing heat through the ducts. even though its cooler, its still above the 71 the thermostat is set at and is, reguardless the fact its lower than body heat, warming the house as a whole. if you put your hand to the register it sometimes is cool but thats just on your skin, it is actually heating the house though. seems almost like a win/win.

What is the cfm rating on the blower?
sq. ft of house?
duct sizing adequate
number of runs...length...?
.....these can all play a role...and are important...but if you are comfortable...then those settings may work in your case....but i would think the blower must run alot....somewhat like a "stirring" set-up...?

I have a snap switch mounted on the air jacket of my furnace that shuts the blowers off at 110 degrees and turns the blowers on at 120 degrees. What I am finding is that when I run the furnace harder (when its colder outside) the blowers are on all the time, which is fine with me for the following reasons. Having the blowers on all the time should give me the most efficient results for heat transfer to the house - AND it keeps the heat more evenly distributed since the air is being rotated thru the house constantly.

When I'm running the furnace low and slow (when its warmer outside) the blowers kick on and off which also has had advantages for the following reasons. Keeps the furnace itself from over heating (as opposed to having the blowers off completely). Saves me some electric, since heat distribution isn't that important when its warmer outside AND allows a little more heat up the chimney to help maintain a draft (which is more difficult when its warmer outside).

So overall, I'm happy with the performance of the snap switch to control the blowers at those temperatures...

fuccillo111 wrote:thanks Len. i hate to mess with something thats running well but i didnt give the factory settings a try either, so maybe ill mess with it. i did, however, set the white feed knob down to 6 turns as opposed to 8 or 9 as factory was. i do feel that with the blower running longer im getting a more constant heat as its pushing heat through the ducts. even though its cooler, its still above the 71 the thermostat is set at and is, reguardless the fact its lower than body heat, warming the house as a whole. if you put your hand to the register it sometimes is cool but thats just on your skin, it is actually heating the house though. seems almost like a win/win.

If it's working I wouldn't mess with it too much. I have mine set at 110 off and 160 on. I like to feel the heat coming out of the registers rather than cool air.

1450cfm blower.
1300 sq ranch although it is in a 1300sq uninsulated basement so I dont know if that means 2600sq total.
Duct work is square and reduces from 20" to 16" to 12" trunk size for aprox 35 ft and there are 9 6" rounds over the course of that 35 ft.

Sizing sounds adequate....(without going into a bunch pressure drop and air flow b.s )...and i will assume you have the proper return air ducts?
....regardless...if u are comfortable...like i said before...ur settinhs may be fine for your situation.
...the limits do the following:
fan on is the temp. setting you select when you want the blower to come on
fan off temp is temp you select that will turn blower off when the temp in the plenum reaches that temp.
The concept is..
-a HIGHER ON temp will provide hotter air initially to the living space...and generally for a longer time....as the temp differential is usually greater(example:on at 150...off at 100)
...this introduces warmer air longer to a cool room
your settings prob work well for a couple reasons..
1- the blower is of adequate size for your system
2-your overall run is relatively short...so you will experience a quick "turn over"
I am heating with a Keystoker A150 furnace...roughly 2200 cfms and my longest run is about 70 (yes...SEVENTY !) lineal feet from the furnace...and that room runs about 2 or 3 degrees cooler than the rest of the house.
As far as burning less coal...well maybe...
I actually lowered my off temp on my switch to 90 (from 100) tonight because temps are predicted to hover near zero outside. i would rather turn air over longer than let my plenum collect it! Lol
i have been considering installing a "stirring" fan (about 600-800 cfm) to run litterally all the time...but havent gotten to it yet
hope this helps...and sorry its long winded!
....btw...im heating over 4000 sq ft ( when you include the basement) and maintain temps of plus or minus 1 degree at all times... keystokers controls are good out of the box... But there are ways to make them much..much better!

Fuccillo111...
1 more thing... I re read your post.. and if I am understanding this correctly... you only have 9 registers in your house?... Each with a 6 inch supply??
... if that is the case.... then TECHNICALLY your blower is actually over sized...
I missed that earlier... on paper... the absolute best your supply lines could handle is 900-1100 cfm total... but this is a topic for a brand new post all together! Lol
... but I will reiterate.... if it works for you... then leave it be
... enjoy the cheap heat!...

I dont understand how you can have too much blower. Isnt that like saying you have too much money? Right now I have two 10" rounds from my cold return feeding my blower, one on each side of it. Maybe it would be more effective to leave one side open to let it draw as much as it wants from the basement. This would also "draw" more air towards the combustion fan right? I just want to maximize my investment, I dont mean to sound anal. Thanks again.

fuccillo111 wrote:Maybe it would be more effective to leave one side open to let it draw as much as it wants from the basement.

I would advise against that.. Heres why.. Imagine your furnace adds 50 degrees to the air coming in thru the cold air return. The air in the cold air return may be 65 degrees + the 50 that the furnace adds = 115 dgree air coming out at the warm air registers in the house.

Now lets try drawing air off the basement floor that may be only 50 degrees + the 50 the furnace adds = 100 degree air coming out at the warm air registers..

I cannot stress enough the loss of efficiency thats going on when people don't have a cold air return and instead pull cold air off the basement floor, pressurizing their house and ultimately loosing that warm air because the air flow replacement is all wrong

fuccillo111 wrote:This would also "draw" more air towards the combustion fan right?

No, actually quite the opposite if the basement is tight. The negative pressure created by taking air out of the basement thru the blower thats disconnected from the cold air return would actually cannibalize your combustion AND chimney draft.

I dont understand how you can have too much blower. I don't think there can be too much blower unless of course it is causing a high wind in your house thats making yer dinner go cold too fast

Fuccillo111...
first of all... according to Obama.. you actually CAN have too much money!! lol
... but what I meant was.... the 6 inch supply duct ( you have 9 of them?) at best can only handle roughly 1000 cubic feet per minute of air. your blower is capable of moving 1400 cfm...
...NOW... a 10 inch round duct can handle approximately 400 CFM... you have total of 2supplying the blower... therefore... your blower is supplied with approximately 800 CFM or so...( a perfect system)
... all I meant was... the blower will most likely NOT out perform the ductwork as far is handling air is concerned
air distribution design takes into account the volume of air to be moved... the desired velocity of the air... and the static pressures developed at the chosen conditions of of volume and velocity
Without working with ALL parameters involved... volume(cfm),speed(velocity), and static pressures( resistance).. a poorly designed system is the outcome

sorry... I wasnt done posting
... you are not being anal... I myself have done everything to maximize my system for both comfort and efficiency.... with my hot air furnace
... I just don't want you to get over concerned... if your house is maintaining a comfortable temperatures... then your system is probably fine
I was only trying to illustrate that your blower will probably NOT out perform your duct work... if it did.. you would have higher velocities of air inside them
.. the bottom line... a slightly smaller blower would work just as well
.. but that is a moot point.. so don't sweat it
... I would not recommend removing a cold air return duct from 1 side of your blower.... that would actually decrease the amount of cold air drawn from the living space
... if it works for you... don't mess with it too much

Rigar wrote:the bottom line... a slightly smaller blower would work just as well

I agree better over powered than under powered

Thanks for the responses. after all that I do feel I have the optimun set up for what I had/have to work with. My step dad has the same model koker as I and the same plenum and return set up too, the dealer actually suggested he leave one side of the blower open to the basement. He gets very good results and burns much less coal than me. He also has a log cabin and better insulation and a tad smaller space....so I guess that explains that. But I feel right now im running optimum for my situation and thats about 40-60lbs/ 24hr and its been cooooold in central ny.