EFM 520

I need help, i have a efm 520 coal stoker currently burning rice from premium coal in tamauqa. The unit has new worm, bushing, blower fan, motor , motor is moving in right direction. I have the old style gear box with the adj connecting rod. the air and feed is set at 4 feed 4 1/2 air. timer is set for 3 min per hour the stoker pot has just been rebuilt. new gaskets, grates were replaced a year ago. stoker either goes out all the time. if i disconect the timer high limit then the stoker over heats. goes up to 260. the problem is also no one is at home during the day, and we only uses it for hot water, summers and heating in winter. i have both returns hooked up but know bypass. my dad has a efm 350 and timer is not hooked up to high limit the gauge dosent move past 170, timers runs for 2 min on his. he has know bypass on his, and only one return, and works great. hope someone can help thanks

No bypass isn't helping, the hottest water will collect at the top of the boiler. I would add a bypass loop when you get time.

In the mean time, try cutting the timer back to 2 minutes per hour and see what happens. Make sure the smoke pipe and chimney are clean, baro is properly adjusted, and also make sure the base is sealed up tight...that includes the door gaskets.

You may also want to try setting the timer to run twice per hour...1 minute or so.

ok i will put the bypass, as of last night the stoker so far is staying lite, i get my coal from tamaqua preiume fine, there seems to be alot of slate and other stuff mixed with it, the stove is at 4 feed and 4 3/4 air timer set for 1 1/2 per half.

ryan20strohl wrote:i get my coal from Tamaqua Premium Fine, there seems to be a lot of slate and other stuff mixed with it

I have no experience with this coal, but keep in mind it is common to have some unburned coal in the ashes when just running on the timer. If you think the coal quality is poor, try a different source next time.

Try 4 feed and 4 air. What are your high and low aquastat settings. Try 130 low and 210 high with 2 minutes every half hour on the timer. Do you know what your chimney draft is when it's firing?

hey guys i figured it out, it was a bad bin augar, it was shot so i just put a 55 gallon plastic drum on the end thanks for your help so far

Glad to hear you found a problem, but I'm having a hard time understanding how lack of coal feed would cause the boiler to overheat... Regardless, if it runs good now you did well.