EFM 520 High Boy

perch · Post by **perch** » Thu. Nov. 13, 2014 2:56 pm

I just purchased a refurbished 520 highboy I'm trying to see if it's ok it's set at 160 and 140 when it calls for heat it goes to 160 then when circ. Pump kicks on it drops to like 125 and circ. Pump shuts off at 145 it only cir. For like 5 mins. Is this ok?then it has to work it's way back to 160?

Post by **Rob R.** » Thu. Nov. 13, 2014 3:26 pm

Sounds like you have a high-mass system, like a bunch of cast iron radiators. If the boiler was piped according to EFM's instructions, you should be able to adjust the boiler bypass to temper the return water and reduce the temperature swings you are currently experiencing. There are some other things you could do, but first tell us a little more about the system, and what feed rate you are using on the stoker.

perch · Post by **perch** » Thu. Nov. 13, 2014 3:58 pm

It's running at 4 feed and 4 air

Post by **Rob R.** » Fri. Nov. 14, 2014 4:54 am

Without knowing how your system is piped and wired, it is pretty hard to advise any course of action. You might have to throttle the flow of return water, or perhaps the stoker needs to be bumped up to 5 or 6 teeth with the air adjusted accordingly. I would increase the high limit setting to 200 degrees, that will ensure the timer runs when it needs to and your fire will be more responsive when there is a heat call.

perch · Post by **perch** » Mon. Nov. 17, 2014 8:34 pm

Turned high limit to 200 temp still drops fast takes long time to heat back up must be circulating to fast any ideas?

Dave 1234 · Post by **Dave 1234** » Tue. Nov. 18, 2014 8:45 pm

As Sting will say, the search for balance is what you need. Getting there can be tough.
Rob and other talented folks will help you. Give as much detail as you can.

Good Luck , Dave

perch wrote:Turned high limit to 200 temp still drops fast takes long time to heat back up must be circulating to fast any ideas?

Scottscoaled · Post by **Scottscoaled** » Tue. Nov. 18, 2014 8:58 pm

Why does the circ pump kick on when the it reaches 160? Shouldn't it come on when it reaches low limit. That is the low limit that the pump will circulate at. Possible to have the hi and low settings switched? Am I not reading this right?

perch · Post by **perch** » Fri. Nov. 21, 2014 4:02 pm

Another question I live on a 2200 sq ft house I have big radiators it's now 20 to 25 degrees outside I keep house like 70 71 degrees I have a 520 highboy what lbs average coal should I be using roughly?