Bituminous not makeing enough heat?

Hi all,
I have a Royall indoor Wood/Coal boiler http://www.royallfurnace.com/IndoorBoiler.htm that I bought in October off CL for $400. So far I've been useing all wood that I cut off my uncles' place and its heated our house to 71* with no problem, Even when it got down to -18. My wife loved the new heat sorce, that is untill the wood ran out. No problem we can switch to coal right? Wrong!
I can't get the water temp. to rise higher than what I set the circulator to come on at (160*). It just stays there and doesn't get any hotter. I need high water temps (170* to 180*) to heat my house since the previous owner under sized the baseboard. With the wood I had NO trouble getting water temps. to 180* and even had problems with it coasting up to 200*.
The only problem I can think of is someone changed the draft blower to a smaller one. The manual calls for a 130 CFM blower but I only have a 75 CFM. It looks like one out of a clothes dryer. Could this be my problem or is it just techniqe that I don't have yet? My Pap always heated with old cast iorn coal boilers and I fired thise many times, Even installed a few.
Sorry for the long post and thanks in advance for your help.

Is there a draft control that lets air come up through the grates from the ash pan area or does the forced draft fan do it all (which appears to be above the grates)?
If all/most of the air is coming in above the grates this would be a problem as coal burns better with air supply beneath the grates and flowing up through the coal bed.

Make sure you have it set correctly. Yes, the less CFM on the blower, the less it will burn and get hot.

Here is one article Greg stated
Hard or soft coal???

Most of us here burn Anthracite. Bituminous is a different creature all together and I can't help you. Maybe one of the Bit burners will chime in with tips. Anthracite wants all it's air from underneath, but I think Bit wants some over the fire too.

you should call royall manufacturing in (elroy) Wisconsin and talk to them about getting the right blower for your boiler. I know that style boiler pretty well. They are made very well and ASME stamped to boot. these units last 30 yrs easy. There is a baffle plate at the blower that directs air above and below the grates. Being that you burn Bituminous this type of set up will be perfect for you. You should try mixing some wood with your coal for a while until you get this boiler working correctly. What size boiler is it the 6130, 6150, or the 6250? Also do not load above the fire brick to much because with shaker grate design you will clog up with clinker and your fire will suffer.

Hello GKG, welcome to the forum. Several good suggestions mentioned above, the one I'd like to emphasize is the airflow. You want your combustion air to be coming through the grates, from below the fire.. Bituminous CAN use some over-the-fire combustion air, especially when fresh coal is added, but once the volitles [sooty smoke] have boiled out of the coal, then the over the fire air is not needed,, at this point Bit coal burns just about like Anthracite.

So: Make sure your comustion air is being forced up through the fire from the ashpan area, with only a little combustion air over the fire.
Check on the fire about 30 minutes after a fresh load of coal is added, to see if the coal has stuck together, I call it bridging, leaving a crust over the hot fire , blocking most of the heat of the fire..
Check to see that you don't have melted together sheets of ash [clinkers] covering the grates, blocking the combustion air to the coal bed.

You should have no problem getting enough heat, with the correct air flow.

How often did you have to add an armfull of wood to the boiler when you were really making heat for cold weather? Every 2-3 hours?? Was the fire a flaming roaring fire, or just a bed of wood-coals ??

Hope this helps.. Greg L

Moving to the Bituminous forum
greg L