EFM Fire Keeps Going Out

So here's the deal, I have a round door 520 in my current house (no insulation on it). I installed it 9 years ago, I burn it year round, and never had an outfire. I just installed a square door 520 in my new house I've been working on. Same Argo controller, same mercury timer, same coal, same aquastat settings, and about the 3rd outfire. Here are some of my observations/concerns: I have it running PEX radiant Ultra fin system in my very well insulated smaller cape cod house. It seems that the boiler holds the heat so well that by the time the aquastat and or timer fires the boiler the fire can't recover. Also, I'd like it to only get to 180 degrees because of the PEX, but a 40 Diff. , 140 the fire will be out. I'm getting really frustrated and really need some insight. Thanks.

What are the settings on your outfire timer? A fairly standard setting would be running the stoker for 2 minutes every half hour

No need to have such a huge differential temp
No need to run 180* thru the pex,if you don't want to.
Use a mixing valve to control the temp thru the pex.
It seems as tho you may have issues with the timer.
Minimum boiler water temp should be no lower than 145*

The timer seems to be working, but since I'm not living at the house yet I can't keep an eye on it all the time. Also, I thought of a mixing valve for the PEX, but how do you use one in a closed system?

keithkeystokerefm wrote:The timer seems to be working, but since I'm not living at the house yet I can't keep an eye on it all the time. Also, I thought of a mixing valve for the PEX, but how do you use one in a closed system?

A mixing valve doesn't mix tap water in,it mixes the cooler water from the return side to temper the incoming HOT boiler water on the supply side.

Windyhill 4.2, Thank you about the mixing valve, I'll look into that. But any idea about the fire? Do I need a 40 degree diff.? i.e. 200/160? My round door boiler sits at 180 all day in the winter or even summer time.

The boiler in the new insulated small house is going to require more hold fire time because of the reduced demand. Too, Im certain that the chimney draft is different one direction or the other. Manometer? You should not be running 180 water through staple up pex system. I would recommend putting in a mixing valve sooner rather than later...

My aqua-stat is set @ 200* on the HI
currently @ 175* on the LO,with a 10* diff.
summertime @ 155-160* on the LO,with 10* diff allows lower water temps for the summer & still keeps the minimum temp @145*+
Never had an outfire.

Outfires are caused by lack of coal, lack of air, or both.

Little to no chimney draft can cause outfires, and plenty of other issues. If you have never checked the draft with a draft gauge, at least check to make sure that the flue pipe is clean, there are no gaps in the pipe, the clean out door on the chimney is tightly closed, and that the flame of a match gets pulled through the hole in the fire door when the stoker is running. A draft gauge (or manometer) is needed to fine tune it, but for now just verify that the firebox is negative compared to the room when the stoker is running.

Also, if the load on the boiler is very light, and you have the end switch of the zone relay connected to the aquastat on the EFM, it will ramp up to the high limit and likely skip timer cycles. If the house only has radiant heat, a simple solution would be to wire the circulator(s) to run independently of the stoker, and let the aquastat control the boiler temperature via the low limit.

An intermittent obstruction at the opening of the auger can also cause outfires. I battled outfires for a month one time and was going crazy...then someone told me to empty the bin and see if I found anything. I found a piece of nut coal that was worn nearly as round as a pin pong ball...it had been rolling around the end of the auger, and prevented the coal from feeding properly.

Regardless of the outfires, you should be controlling the temperature of the radiant zones with a mixing valve.

I made a post the other day about my EFM 520 I installed not keeping the fire lite. Again, I have a round door one where I currently live for 8 years and no problems. My new square door is giving me BIG problems, and the fire keeps going out over night. It seems to be running up past the high limit, and retains the heat so well that by the time it reaches the low limit the fire is out. I have my mercury timer set to run 2 1/2 minutes every half hour, coal and air set at 4 and 4, and high 185 low 145 with 10 diff. Could the aquastat be bad? What they heck am I doing wrong!? HELP!

The high limit setting of 185 is a big part of the problem. It needs to be at 200.

Do you have a bypass installed?

I have never seen the need to set the timer for more than 2 minutes every half hour.

Since this is still about your out fire problem, I will merge it with your other thread.