EFM 520 coal/fuel oil boiler setup

Post by **StokerDon** » Thu. Jan. 02, 2020 7:20 pm

Well, the only thing I have left is the relay in the aquastat might be stuck on the HI side. Does the relay click on and off when you short the T T terminals?

-Don

CarlMac · Post by **CarlMac** » Mon. Jan. 06, 2020 5:15 pm

There is no bypass loop on this system

CarlMac · Post by **CarlMac** » Mon. Jan. 06, 2020 5:17 pm

StokerDon wrote: ↑
Thu. Jan. 02, 2020 7:20 pm
Well, the only thing I have left is the relay in the aquastat might be stuck on the HI side. Does the relay click on and off when you short the T T terminals?

-Don

Yes, the relay clicks when shorted. But even on oil if I raise the hi limit it immediately kicks on. It wants to keep it pegged at the high temp, not the low

Post by **Rob R.** » Mon. Jan. 06, 2020 8:10 pm

Something is wrong with your aquastat. I would replace it.

Budsnblues · Post by **Budsnblues** » Sat. Jan. 09, 2021 10:05 am

I have a EFM 520 and switching from oil to coal. The Aquastat ( written on the cover) says 140-220- for coal. It burned nice for the firt 3 years, but we switched to oil and had a guy come in and clean the filter and nozzle. Went back to coal and it didn't burn well after that. Any help? I didn't ever change the setting since I first moved here. I don't know much about it, but learning. Too cold in this basement using the oil, and figured the coal would at least have some radiant heat.