EFM 520 coal/fuel oil boiler setup

CarlMac · Post by **CarlMac** » Sat. Dec. 28, 2019 3:59 am

Hello, I am new to using the 520 boiler. I have gotten a lot of good information from here. My boiler is currently running fuel oil and I'm trying to switch to coal. I set my thermostat to 190/140 with the differential at 15. The stoker did not shut off until water temp was around 210 and the timer will not activate the blower for the run every 30 minutes. Any suggestions?

Post by **StokerDon** » Sat. Dec. 28, 2019 8:08 am

Welcome to the forum.

Where do you have the triple Aquastat mounted? Where to you have the temp/pressure gauge mounted?

Did the stoker run right up to 210 degrees, or did it go to 210 degrees after the stoker shut off?

If your unit is wired as in the install manual, the timer cannot run the stoker when the boiler is above the HI LIMIT on the Aquastat. This is a safety feature.

-Don

Post by **coaledsweat** » Sat. Dec. 28, 2019 8:32 am

Lower the high limit to 180° and then find something else to worry about. Overshoot is normal with solid fuels.

Post by **Rob R.** » Sat. Dec. 28, 2019 8:55 am

I would start with EFM's suggested aquastat settings - which are 160 low, 200 high, and a differential of 10.

It is possible your aquastat or gauge are off by a little bit, but they should be within ~10 degrees. As Don pointed out, if the boiler temperature it as the high limit setting the timer won't be able to operate the stoker. Typically the DF units have a switch that disables the timer when burning oil - make sure that is in the correct position (you can remove the timer cover and verify it is getting power).

CarlMac · Post by **CarlMac** » Sat. Dec. 28, 2019 11:31 am

The timer is spinning. The aquastat is mounted on the outside of the unit. The thermometer is on the boiler itself. The coal just will not stay lit. I have checked all the wiring comparing it to the wiring diagram and all appears to be correct

Post by **Rob R.** » Sat. Dec. 28, 2019 11:36 am

That is a good start. Can you tell how the timer is currently set? 2 minutes every half hour is where I would start.

What is your feed rate and air setting?

CarlMac · Post by **CarlMac** » Sat. Dec. 28, 2019 1:01 pm

Blower is at 4.5 and feed is 3.5

Post by **Rob R.** » Sat. Dec. 28, 2019 1:19 pm

Increase the feed so it grabs 4 teeth on every stroke, and reduce the air to 4.

Do you have a draft control installed on the smoke pipe?

CarlMac · Post by **CarlMac** » Sat. Dec. 28, 2019 1:36 pm

Yes there is a draft control on the side of the exhaust pipe

Post by **Rob R.** » Sat. Dec. 28, 2019 1:49 pm

Make sure it operates freely.

If the boiler and smoke pipe are clean, the draft is correct, and you are running the settings described above, the fire should no go out. If it does, I would check the inlet of the auger for an obstruction. Also make sure your clean out on the bottom of the pot closes tightly.

CarlMac · Post by **CarlMac** » Sat. Dec. 28, 2019 4:46 pm

Set the aquastat to 140 and 190. Water temp is 220 so still no good. Any suggestions?

CarlMac · Post by **CarlMac** » Sat. Dec. 28, 2019 7:18 pm

Fire still went out. 4 tons of coal and can't burn it.

Post by **Rob R.** » Sat. Dec. 28, 2019 7:21 pm

Something simple is wrong. These are very reliable machines that run well if setup correctly.

It might be time to call someone familiar with stokers to look it over.

leward · Post by **leward** » Sat. Dec. 28, 2019 9:11 pm

Check and confirm the airholes are all clear in the grates, and check that the pot is not plugged with fines and that the cleanout plates are shutting completely. Check there are no air leakes in base from door, rusthole ect. Has to be something simple.

CarlMac · Post by **CarlMac** » Sat. Dec. 28, 2019 9:28 pm

I have a service contract with my fuel oil company. Seems to me like an aquastat issue. High temp at 180, diff of 10 and it doesn't cut out until water temp is almost 220.