Spoke too soon-Econoburn fan issue

Start admitting you need storage and you are in direct competition with Garn. Hmmmm?

It's the Euro way and also the reason Martin designed the Garn the way he did some 30 years ago. Adequate..........and I do mean adequate in terms of gallons per output of the boiler as well as the load served. It just takes a lot of complexity, babysitting and complication out of wood burning.

Mark O'Dell told me that when they started selling EconoBurn he estimated that maybe 5-10% of the units went in with storage. The percentage is now over 80% from what he told me. Sounds like people are getting on the right track for gasification and btu storage to me. That's a good thing.

I am going to chime in here one more time, and then I'm going to call it a day.

The issue with the econoburn controls is not one of idling or thermal storage... it's one of control reliability and functionality. There is nothing wrong with running a forced draft gasifier without storage, providing you have adequate control over the draft and, well... the controls... they need to work for goodness sake. If the controls work, and the homeowner burns responsibly, there will not be major issues, and the units will perform admirably.

The recent discussion here at hearth.com has pressed a few buttons at econoburn, and I had a few productive and actually very friendly email exchanges with dale today. I shared with him my thoughts on adding a time delay relay to bypass the nimbus board on fan startup, providing full voltage until the fan was past the capacitor stage, at which point the time delay would de-energize and then run normally through the nimbus board, providing both high and low fire, as well as idle. His response:

Duane,
I believe this will work, at the same time it will also take the burden off the nimbus upon start up. I will look further into it.
Thanks

Dale


This is encouraging to me, and should also be encouraging to everyone else that it appears they are getting the message, are willing to admit that there is an issue, and hopefully plan to rectify the situation with a real fix and not just a band aid. People spent a lot of money on their econoburn boilers, and they deserve to have this type of issue resolved.

On a very positive note, econoburn has been valiant at repairing and fixing issues with the vessels themselves... when there is a leaky or cracked vessel, or even a bad weld in an area that doesn't involve water leakage, there are no questions asked, they simply either replace or repair. If they move forward with that same mindset on the controls, they might just do ok long term.

Heaterman... if 80% of econoburn boilers are being installed with thermal storage these days, I will eat an econoburn boiler. There's just no way that is true. Not that it matters a whole lot one way or the other, but part of the beauty of forced draft is that people don't need to spend the money up front for storage... and if they were going to spend the money on thermal storage, they would not be buying a forced draft unit when there are draft induction units that cost equal or less money, and don't have issues with backpuffing and smoke spillage into the house because of stack thimbles exiting below the top of the upper chamber door. Just my $.02.

Cheers

I have a tentative thought for something that might be much simpler than the time delay relay.

Right now, the high limit mechanical aquastat is placed between the output of the Nimbus speed controller and the blower motor.

I've noticed on my unit (EBW-150, arrived August 2008 and placed in service January 09) and just re-confirmed, that if the fan is running at low speed and I turn the entire unit off (such as to load wood) and then turn it back on, the fan starts out at high speed for a very brief moment, and then settles back down to the low speed. You almost wouldn't notice it (the brief full speed fan) if you weren't trying to observe it.

This suggests to me that the Nimbus speed control may itself be set up to start motors on full speed, then drop down to a reduced setting, in order to avoid the "slow start current overload" that seems to be at the root of the problems being discussed here. That would make sense, as a situation with a motor struggling to start is not only bad for the control (current overload) but also for a motor.

If indeed the Nimbus operates that way, and if the mechanical high limit aquastat were moved [in circuit placement, not physical location] to interrupt power to the supply side of the Nimbus, instead of the output side, then all would be well.

From looking at the circuit/ wiring diagrams [see www.woodheating.ca/EBInstalMan.pdf print-numbered pages 14 and 16] I am not seeing any aspects of the circuit that appear as if they would be negatively impacted by that change-- but I invite more eyes and grey matter to see if there's a hole in my thinking.

Also, can anyone else confirm whether the Nimbus does indeed start [from a no power input condition] with a brief full speed output? Do other peoples' EBWs with the 2-speed fan display the same behavior as mine [with the really brief burst of full speed blower operation if the boiler is powered off, and then back on, when it is set/ running so that the blower is otherwise at low speed]?

AHA! Just confirmed that the Nimbus speed control does indeed, when first powered-up, give a brief burst of full speed output:

See Nimbus manual, page 8, lower left:

"Start Pulse: Some fans that run just fine at lower
voltages will not start at these voltages; therefore the
Nimbus will start fans at full voltage for 2 seconds before
throttling back to the appropriate control speed."

AT:
http://www.controlres.com/pdf/Nimbus.pdf

So-- the only remaining issue, I think, is whether there's any drawback to moving (electrically speaking) the high-limit mechanical aquastat to control the power into, rather than the power out of, the Econoburn's Nimbus. I cannot see any drawback, but invite others to see if you can identify anything that I am missing.

mtnmizer said:

A good number of devices with these new boards used in appliances have given me problems, my new Weil-McLain boiler shuts down after a power outage and has to be rebooted. Not a comforting thought when leaving in the winter for
a few days. The factory sent out a relay box to put inline but not much of a fix IMO. The older controls use on maytags are
far more reliable than the new electronics according to the appliance repairmen I've spoken with. Even high end
Viking ranges are prone to board failure.

Click to expand...

Don't get me started on Viking ranges. I own one that I bought during a (now long ago/over) high-earning window in the late '90s, on the thought that buying a top quality item would cost less, in the long run, than a more regular-grade item. It's been plagued with ignitor issues for both the oven the burners. I have been able to repair it myself, but it is ridicuous that it was not designed more robustly, or at least in a manner that'd be easier to service when certain parts that _will_ fail, eventually do.

Too many products these days are designed in a manner that they end up being throw-aways (infeasible or uneconomical to service)(or unique proprietary parts that become unavailable after a few years).

One of the main things that attracted me to, and continues to impress me about the Econoburn is that it is designed and built in an extremely robust manner- both the metalwork and the controls (which are all standard industrial/ commercial grade parts). It's the total opposite of a modern throw-away product- which is what I want for a product involving this degree of dollar and effort investment.

The last few years have been a "wild ride" in the wood boiler field [look at the Greenwood, or worse, the Adobe] and I accept that there are often some inevitable unforeseen glitches that need to be worked out on many products.

Even though the Econoburn's controls may need some refinement, I am glad that they use standard parts, and "accessible/ understandable modes"- that users can repair or figure out/ refine.

Trevor when I shut my eb 150 off when the fan is in low speed , and then turn it back on it starts off in high speed for a short time. My boiler was manufactured in August 2008 and installed in Oct of that same year. In Feburary 2009 the 2 watt fuse blewout during the night with no ryme or reason. I replaced it and haven't had any problems aside from the alarm sounding occasionally. I am very happy with my eb -150 . No thermal storage .

Piker said:

I shared with him my thoughts on adding a time delay relay to bypass the nimbus board on fan startup, providing full voltage until the fan was past the capacitor stage, at which point the time delay would de-energize and then run normally through the nimbus board, providing both high and low fire, as well as idle. His response:

Click to expand...

Is the fan capacitor start? I didn't think you could use a Nimbus on a capacitor start fan...
Does the fan have a centrifugal switch for the start circuit like say a pump motor?
Also what happens if you raise the minimum speed on the Nimbus?

As far as the Econoburn goes I would like to see them succeed and I don't own one. No reason for "higher" tech boilers not to be made in the US,
we need more like Eco and garn... Need some US made lambda controlled boilers as well.

b33p3r said:

[del][/del]That's why i started the post. The fan starts in high and ramps down..........mostly. But I was present at the boiler when it came out of idle(the aquastat contacts closed) and the fan did not go into high. It seems to have tried to start in low and just sat there and hummed. I was only present for this once but I have walked in on the idle humming motor at least 1/2 a dozen times within the week. It sounds like the ball is rolling on a fix. Thanks to everyone for the support. I'd like to also publicly thank Dale from Econoburn for his patience with my frustration

Click to expand...

Sounds like the Nimbus is not starting the fan with a full voltage pulse. My Nimbus controls on my pumps most definitely start at full speed for a second
or 2 and then ramp back.

b33p3r said:

I just read up on the Nimbus board. The nimbus will start the motor at full speed for 2 seconds. But if the aquastat is opening/closing the output signal of the Nimbus, The Nimbus will think it already gave the motor its start signal? Unless the nimbus senses the interruption on the output?

Click to expand...

Nope, senses on the input only as far as I know.

Ya know.............The technology to make the Econoburn or any other similar unit truly variable speed is out there on the market right now. The Wilo ECO line of pumps for example has the capability to monitor water temperature and increase/decrease speed accordingly via a water temp sensor. Seems to me that the same thing could be done with a draft fan provided it was equipped with an ECM motor. Of course the draft fan would cost upwards of $400 but a person would have a boiler that would come as near as possible to matching the required load. A nice additional feature of this type of motor is a sharp increase in starting torque. It seems to me that application of that on the front end along with the ability to damper or shut off a corresponding number of flue tubes would likely get you down to as low as 40% firing rate. This would drastically reduce the size of storage required but still avoid total combustion shutdown. On the negative side it would probably add about 10 Franklin's to the unit price and a fair amount of complexity with a servo of some kind modulating the heat exchanger capacity.

AFA EconBurns upcoming control.......all I can say at this point is that it will address the issues raised here and add a few more features when available. From what I see on paper, it will definitely improve the product and also interface with planned upgrades to combustion technology in other areas. I believe they are going though the approval process right now.

b33p3r said:

After further reading, I'm gonna throw my 2 cents in here. All feedback is appreciated. I belive this is the wrong controller for the application. This controller is more designed for blowers used for cooling. The logic of the controller, if I'm reading things right, when used in Temp control mode will turn the fan off when temp falls below programmed setting. Basically if the sensed equipment cools down enough the blower will turn off. That being said, our boilers are not using temp control. They are using voltage control. They could not use temp control because we would want to turn the fans on if the temp dropped, not off. So yes you could use voltage control as we do, but why not use a controller logically built for heating control and use the temp inputs to regulate your induction fan? And yes turn the fan off when a predetermined high temp is sensed. Then you can leave the aquastat on the output side of the blower and use it strictly as a safety shutdown rather than a control shutdown.
There is a lot of functionality in the nimbus that is not being used because it is not geared towards heating control.

Click to expand...

Some of the literature associated with the Nimbus focuses on fans and cooling simply because those are good markets to pitch the product to. There's nothing about the Nimbus that limits it to that-- or anything that makes it "wrong" for the use in the Econoburn. Some of the folks here on the forum are using it to control pump speed

There are features of the Nimbus (the potential for variable speed control) that aren't used in the current Econoburn configuration, but that's got nothing to do with whether or not the Nimbus could be used that way in this application. Feed it the appropriate standard variable inputs (4-20ma or 0-10volts) that is being varied in the right way in response to operating conditions, and it would do lots of things. It's just that the devices and programming to do all that get a lot more complex than the existing system in the EBW-- and they apparently did not want to "go there" in the first iteration.

There may well be an issue with motor start load at low speeds, and how/ where the switching is done, but that does not make the Nimbus or any other part of the basic approach "wrong", within the limits of the balance of simple vs. complex that were decided on and embodied in this product.

kabbott said:

b33p3r said:

I just read up on the Nimbus board. The nimbus will start the motor at full speed for 2 seconds. But if the aquastat is opening/closing the output signal of the Nimbus, The Nimbus will think it already gave the motor its start signal? Unless the nimbus senses the interruption on the output?

Click to expand...

Nope, senses on the input only as far as I know.

Click to expand...

Once the Nimbus receives power, it is going to be oblivious (as far as the start-up full-speed pulse) to any switching on the load side of the Nimbus control.

pybyr said:

kabbott said:

b33p3r said:

I just read up on the Nimbus board. The nimbus will start the motor at full speed for 2 seconds. But if the aquastat is opening/closing the output signal of the Nimbus, The Nimbus will think it already gave the motor its start signal? Unless the nimbus senses the interruption on the output?

Click to expand...

Nope, senses on the input only as far as I know.

Click to expand...

Once the Nimbus receives power, it is going to be oblivious (as far as the start-up full-speed pulse) to any switching on the load side of the Nimbus control.

Click to expand...

Pybyr,

I have already emailed dale on your ideas.... I haven't looked at the wiring schematics for the Econoburn yet, but if the fix is this simple, and I think you're on to something here... this is going to save a lot of people a lot of headaches...

I can't remember exactly how the nimbus receives power, but for some reason I am thinking the aquastat might have to be upgraded to a DPDT though... but I could be mistaken.

-duane

theoretically, the alarm 2 over temp relay should be switched on the other side of the numbus as well.

cheers

Duane (Piker)-

I'll be very interested to hear Dale's take on this. And glad if I helped spot a solution.

Trevor

Pybyr,

Dale eluded today that he didn't think it would work, but didn't really explain why. I looked at the econoburn wiring schematics a little bit this morning, but I just don't have time to investigate this myself right this instant, as I am trying to finish up a big solo plus installation with 1000 gallons of thermal storage before the end of the year so my customer can get the tax credit... It sounds like your idea has sparked some thought though, and I think eventually we'll get a fix in place that is something along those lines... hopefully. To be honest, the control issues on these boilers have really been a pain. I think it's great that they are working on getting a new control in place... but that doesn't help the existing customers... gotta get the old controllers up to par that are already in the field.

cheers

UPDATE:

First all, I want to thank Pybyr (Trevor) for catching the fact that the nimbus already has a 2 second time frame where it supplies full power to the fan before ramping down to low speed. This is something that I have experienced every time I turned an econoburn on, but it just never really clicked in my head I guess...

At any rate, after reviewing the econoburn control schematics when I should have been working, and after a few more emails with dale today, we have a plan that we're going to try on a few units. His concerns earlier that moving the aquastat wouldn't work were based on not wanting to see line voltage through the aquastat... but we can still switch the nimbus through teh neutral... so the scenario brought up by trevor should work. I have also proposed that the alarm 2 overtemp relay also be rewired to feed the nimbus board rather than the reverse, and the fan be connected directly to the nimbus... this way, regardless of whether the mechanical aquastat opens, or the overtemp alarm opens the alarm 2 relay, we are cutting supply voltage to the nimbus, giving us our necessary 2 second full voltage pulse to start the fan when the boiler calls for heat.

Theoretically, you really shouldnt have to worry about the wiring on the alarm 2 relay since the mechanical aquastat should be set below the alarm 2 setpoint, but the fact is, the controls tend to jump around on some of these units, and can alarm out at times when temps are normal... so in an attempt to keep the jumpy controls from putting additional strain on the nimbus, I think it's best to change the wiring around.

I have a few boilers in the field that I am going to rewire - units that haven't failed completely, but that are having fan startup issues. If this fix works, and i am feeling pretty confident about it, we can hope that econoburn will perhaps send out some sort of bulletin on the matter to help prevent further premature failures. We'll see.

I must admit... helping out a company that is now my competition is not real high on my list... but the bottom line is I have plenty of econoburn customers who deserve to be satisfied... both through hillside energy and also from my time with econoburn as a sales rep... so i guess you gotta do what you gotta do.

All for now... but feeling fairly positive about the matter. Thanks again Trevor, and to the forum as well for being a place to hash this kind of thing out.

cheers.

UPDATE:

First all, I want to thank Pybyr (Trevor) for catching the fact that the nimbus already has a 2 second time frame where it supplies full power to the fan before ramping down to low speed. This is something that I have experienced every time I turned an econoburn on, but it just never really clicked in my head I guess...

At any rate, after reviewing the econoburn control schematics when I should have been working, and after a few more emails with dale today, we have a plan that we're going to try on a few units. His concerns earlier that moving the aquastat wouldn't work were based on not wanting to see line voltage through the aquastat... but we can still switch the nimbus through the neutral... so the scenario brought up by trevor should work. I have also proposed that the alarm 2 overtemp relay also be rewired to feed the nimbus board rather than the reverse, and the fan be connected directly to the nimbus... this way, regardless of whether the mechanical aquastat opens, or the overtemp alarm opens the alarm 2 relay, we are cutting supply voltage to the nimbus, giving us our necessary 2 second full voltage pulse to start the fan when the boiler calls for heat.

Theoretically, you really shouldnt have to worry about the wiring on the alarm 2 relay since the mechanical aquastat should be set below the alarm 2 setpoint, but the fact is, the controls tend to jump around on some of these units, and can alarm out at times when temps are normal... so in an attempt to keep the jumpy controls from putting additional strain on the nimbus, I think it's best to change the wiring around.

I have a few boilers in the field that I am going to rewire - units that haven't failed completely, but that are having fan startup issues. If this fix works, and i am feeling pretty confident about it, we can hope that econoburn will perhaps send out some sort of bulletin on the matter to help prevent further premature failures. We'll see.

I must admit... helping out a company that is now my competition is not real high on my list... but the bottom line is I have plenty of econoburn customers who deserve to be satisfied... both through hillside energy and also from my time with econoburn as a sales rep... so i guess you gotta do what you gotta do.

All for now... but feeling fairly positive about the matter. Thanks again Trevor, and to the forum as well for being a place to hash this kind of thing out.

cheers.

Glad that this may be a solution!

And glad to be part of this mutual- assistance and learning effort that the Boiler Room makes possible.

Couple of thoughts/questions for Piker...
Doesn't the aqua stat switch line voltage now and if you switch the neutral your still switching line voltage...
I have not looked at the Econoburn diagram but with the NFCS if you break the 4-20 mA control line the nimbus gives the 2 second full voltage
pulse when you re-connect it. Not sure what signals the high/low speeds on the Nimbus with the Econoburn.
If you REALLY don't want to switch the line voltage with the aqua stat use a relay???

kabbott said:

Couple of thoughts/questions for Piker...
Doesn't the aqua stat switch line voltage now and if you switch the neutral your still switching line voltage...
I have not looked at the Econoburn diagram but with the NFCS if you break the 4-20 mA control line the nimbus gives the 2 second full voltage
pulse when you re-connect it. Not sure what signals the high/low speeds on the Nimbus with the Econoburn.
If you REALLY don't want to switch the line voltage with the aqua stat use a relay???

Click to expand...

You are correct that the aquastat has 110v being switched through it... but it's not "hot" with respect to ground. I think the reasoning behind dale wanting to switch the neutral instead of the hot is that you can't (or at least shouldn't) get shocked between the neutral and the ground. Lots of customer's play with their aquastats - take the covers off and such... and if you're leaning on the boiler and touch the neutral you wont get zapped unless you somehow provide a faster path to ground than the ground wire itself... which isn't likely.

In case someone reading this thread stops at this post, I have edited here to note what pybyr made clear a few posts down... if the switch on the aquastat is open, there is 120v waiting on one side of the switch that will definitely travel through a person to get to ground if it can.

I suppose either way you look at it... whether you break the control signal or the line or the neutral... we need to get that 2 second full voltage pulse. Rewiring the alarm 2 overtemp relay to feed the nimbus and switching the neutral to the nimbus through the aquastat should achieve this, while keeping the homeowner safe.

cheers