eko 40 over burn

[newt191]

My brother has a eko 40 installed inside a 40 by 60 shop with radiant heat and spray foam isulation throughout. On four ocassions in the last week when the room temp was satisfied the boiler reached 210 and ran the E2 code. At this point I have not found any reason for this and am looking for some ideas. I have a eko40 and have been burning for 2 years with no problems like this.

 

[Nofossil]

Here's my guess: If you build too big a fire (especially with smaller and drier wood) and don't have storage, the boiler will produce too much heat even after the fan shuts down.

If you're running a bigger boiler and don't have storage, you have to build small fires.

 

[mr.fixit]

Mine did that a couple of times before I had the storage hooked up. I just ran it at a lower temp. setting,say 170-175 instead of
185-190.It didn't do it after that. Gives you a little over run room. Hooking the storage up solved the problem completely.

 

[newt191]

The temp that we are running at is 160 and the over shoot is going all the way to 210 and going to e2. I just tried a test on my boiler and and turned off the circ pump for the boiler and waited for 1 hour with no heat load. 0 deg gain. If this is the case I dont see how the size of the fire should matter.

 

[newt191]

My thought is that maybe we have a air leak that is causing the gain. Any comments?

 

[sdrobertson]

My thought is that maybe we have a air leak that is causing the gain. Any comments?

Sounds like a air leak. I would try closing the pie vents on the fan when you shut it down. This will tell you if the small "flaps" behind the fan are sticking open and allowing allot of air to flow through when the fans shut down. Another place would be the by-pass damper in the back of the firebox. It won't take a large amount of air to keep the fire really cooking. Does the circ pump keep running or does it shut off when the fans stop?

 

[Gooserider]

My thought is that maybe we have a air leak that is causing the gain. Any comments?

Sounds to me like an air leak, no experience with these myself, but from what I've seen, number one suspect is the bypass damper - make sure it's closing tight, and that the gasket is sealing well...

Also I would echo the concerns about what the circs are doing - you should definitely have a temperature where the circs will kick on and stay on in order to pull the excess heat out of the boiler, regardless of any thermostat setting or other "call for heat"....

What is your brother running for a heat distribution system - any chance it isn't putting enough of a load on the boiler?

Gooserider

 

[Tony H]

The EKO does have an issue with the boiler pushing the damper open . This has happened to me when I had too many small dry pieces wood pallets in my case and the boiler can not handle the volume of wood gas and produces a "pop" where exploding wood gas is pushed back into the upper chamber and pushes the damper open. The first couple times I had no clue then it happened when I was standing next to the boiler and witnessed it.
There have been some threads on this and I use a vise grip on the damper arm so it can't open , others have made a y forked rod to fit in between the handle and body of the boiler. The other thing that will help is leaving the cleanout handle in the forward position as this blocks the damper .
I have had full wood and lots of idle time on a day that was warm and with the boiler set at a low level never had the boiler run away except when it gets that extra air from the damper opening.
If he has his pump shut down or has a really small loop he needs to add an overheat zone so the boiler can release the heat somewhere.

 

[taxidermist]

Do you have your boiler protection loop all the way open? If so you need to close it to about 1 to 1 open. I can get my boiler to shut down when the water in storage is only 120 because it just keeps circulating it around the boiler till it reaches 195 then shuts down.


Rob

 

[newt191]

Thanks for all of the ideas. TO start my brothers unit is running with 9 loops of 300 ft in 5"slab. When the problem starts the thermostat has been satisfied and shuts off the circ to the floor. After the eko reaches the 160 setpoint the fan stops and the circ pump on the unit continues to run. With in 15 mins after the fan shut down the boiler is well into the 190 and will not stop until the e2 code. During this point there is very little heat load due to the floor pump being off. As I tried with my unit by shutting off the circ pump on my boiler this should not cause any problems. Both his unit and mine are both plumbed the same with no heat storage, and no over temp loop. This has not been a problem for me over the last 2 years. I will be checking the seal on the damper and fan flapper tonight and will let you know my findings. Thanks again.

 

[twitch]

From what you've just described, I would think it would have to be an air leak. Does he have a draft inducer in the chimney connector pipe? That might cause air to go through the fan damper.

 

[ihookem]

Mine did that when I first started it. The temp went up very fast. We figured it didn't have all the air out yet and air got stuck where the thermostat was. It never happened again.

 

[newt191]

I have checked the damper and the flap on the back side of the fan and found no problems with either. We have also added a second probe on the top of the boiler next to the control probe with the same reading ruling out a possible faulty probe/controller. At this point I am unable to explain the rapid rise in heat and the differance in the two boilers. We have started to run the boiler for only one burn per day and will continue to search for answers.

 

[sdrobertson]

I have checked the damper and the flap on the back side of the fan and found no problems with either. We have also added a second probe on the top of the boiler next to the control probe with the same reading ruling out a possible faulty probe/controller. At this point I am unable to explain the rapid rise in heat and the differance in the two boilers. We have started to run the boiler for only one burn per day and will continue to search for answers.

I'm thinking the boiler is really over-sized for the heat load. If there is no air leak and it heats up that fast after the zone is satisfied then the boiler must be really cooking when it shuts off the zone. It wouldn't take long to heat the water in the boiler and then it overheats. I'm thinking that if you can eliminate the thought of any air leaking into the boiler causing the overheat, then he will have to use small fires so that when the zone is satisfied there is little fuel in the boiler or he could add some storage as then he could burn a full load and then live off the storage until its time to build another fire. With his head load and being radiant he should be able to run cooler water and still get the btu's he needs which would make storage even better and last a longer time. This may be a blessing in the end.

 

[leaddog]

I'm thinking you must have to much draft so you are pulling in air to keep enough fire going to over heat. Or you have a air leak at the doors.
The other thing is you have really hot coals going and with very little system water you can't get rid of the heat.
You might put in a aquastate to turn on your zone pump at say 194* and keep the controler from shuting down. It would work the same as a overtemp system.
leaddog

 

[ihookem]

This just happened to me today. It was not air. The Dandfoss valve was stuck. I'm almost sure of it. it went to rest @ 180 very quick and the house gauge was 93. I went out thinking the fire went out but was @ 190r and rising. I turned the ball valve to force the water to bypass the valve. It went down very fast to 132* and slowly went up to temp and is doing fine. he only thing I did different was let the fire go out last night because it was so warm and 72* in the house. Never happened before, hope it never happens again.

 

[Tony H]

This just happened to me today. It was not air. The Dandfoss valve was stuck. I'm almost sure of it. it went to rest @ 180 very quick and the house gauge was 93. I went out thinking the fire went out but was @ 190r and rising. I turned the ball valve to force the water to bypass the valve. It went down very fast to 132* and slowly went up to temp and is doing fine. he only thing I did different was let the fire go out last night because it was so warm and 72* in the house. Never happened before, hope it never happens again.

If the valve was stuck would that mean the valve has failed ? Would the unit need to be replaced?

 

[ihookem]

It's the only thing I can think of. I wouldn't have to replace the whole valve, it has a car like thermostat in it. Just change that. I hop I'm wrong but don't know what else it would be.

 

[Hunderliggur]

For the OP - there is a possibility that he circulator on the boiler is undersized to push any water though the slab when the house circulator shuts down. In that case th circulator witll "run" but no water will move, quickly leading to an overtemp. Since this is a common occurance you may want to install a larger circulator to push the water though the slab when the house circulators are idle and/or and an overheat dump (fancoil and fan - like a car radiator) at the boiler that is fed by the boiler circulator or thermal statification.

 

[newt191]

Thanks to all. It looks like the problem has been solved by adding an aquastat to the floor loop to dump the heat when the boiler temp rises above 180. Asw this has fixed the over heat problem for now I expect that when the outside temp starts to rise the floor will become to warm to dump to any more and will have to change back to one burn per day. This still does not explain the differance in my boiler and my brother but this may never be explained. Again thanks to all it is nice to have a place where people are educated in the boilers and you can bounce ideas around.

 

[gorsuchmill]

Could it be too much draft? Despite similar set-ups, if your flues are different or your houses sited differently (i.e. top of a hill, in a valley, etc.), then it's possible his flue is drawing more air than yours, such that even if the draft fan stops he's still getting a meaningful burn. If so, a barometric damper might be able to calm it down some.