Needed a solution for gas boiler not charging 800 gallon water storage for EKO.

[GibsonGuy]

I have an EKO 60 w/ 800 gallons of water storage. The system is open and when we did the final install we had a very difficult time getting it to prime to get the water flowing properly. It is a simple system w/ one pump going into the EKO and another in my basement to push the return water. There are no heat exchangers within the tank. The pumps run at a slow setting 24/7 and it hasn’t stopped with the exception of two short power outages, I believe they were very short because prime was not lost. The system works wonderfully. I have left the house unattended for two and three days and both times have returned to a house that is in the mid 60’s w/out back up heat. Most days I burn from 5-6 hours to fully charge the tank and then I’m done.

This is my problem. I have a heat exchanger where the EKO supply meets the house boiler. I have been told that if the fire is out and the water storage has cooled, the gas boiler will heat the 800 gallons of water as well as the house, thru the heat exchanger. This would not be a good situation as my gas boiler is relatively small and it would have a difficult time doing double duty, where the EKO handles this w/ ease. I think I could put simply re-plumb a section that would bypass the heat exchanger and I could manually make the switch. The down side is that it would be all gas or all wood. Or better yet, could something be installed within the line that would electronically switch the system over? This way I could leave for extended periods with the wood being utilized and when the hot water produced by the EKO ran out, the gas boiler would take over.
The final install was done by a licensed plumber and I was very pleased with his work, but I’m afraid it was just too simplistic of a system.

 

[Nofossil]

I have an EKO 60 w/ 800 gallons of water storage. The system is open and when we did the final install we had a very difficult time getting it to prime to get the water flowing properly. It is a simple system w/ one pump going into the EKO and another in my basement to push the return water. There are no heat exchangers within the tank. The pumps run at a slow setting 24/7 and it hasn’t stopped with the exception of two short power outages, I believe they were very short because prime was not lost. The system works wonderfully. I have left the house unattended for two and three days and both times have returned to a house that is in the mid 60’s w/out back up heat. Most days I burn from 5-6 hours to fully charge the tank and then I’m done.

This is my problem. I have a heat exchanger where the EKO supply meets the house boiler. I have been told that if the fire is out and the water storage has cooled, the gas boiler will heat the 800 gallons of water as well as the house, thru the heat exchanger. This would not be a good situation as my gas boiler is relatively small and it would have a difficult time doing double duty, where the EKO handles this w/ ease. I think I could put simply re-plumb a section that would bypass the heat exchanger and I could manually make the switch. The down side is that it would be all gas or all wood. Or better yet, could something be installed within the line that would electronically switch the system over? This way I could leave for extended periods with the wood being utilized and when the hot water produced by the EKO ran out, the gas boiler would take over.
The final install was done by a licensed plumber and I was very pleased with his work, but I’m afraid it was just too simplistic of a system.

Is there any chance you could sketch out a simple schematic, scan it / take a picture of it, and post it?

I'm a big fan of hooking heat sources up in parallel rather than in series. There's some tricks that you can play to determine which source is active at any time. For instance, I have two-stage thermostats where the backup heat source is controlled by the second stage contacts. Perhaps you could use a relay to shut off the EKO circ when the gas is active.

If the EKO water jacket is circulating water from an open tank, I'd have some concern about corrosion.

 

[GibsonGuy]

Thanks for your reply. I'll draw something up this evening. I'm hauling wood today because the school I work for had their snow covered roads turn to ice w/ the rain last night. Tonight we're supposed to have blizzard conditions so I'm taking advantage of this short spurt of mild weather. Quite sure I'll be home again tomorrow, good old northern MI.

As far as the open system, what can be done? We treated the boiler w/ the initial firiing with a liquid of some sort. Does this treatment have to occur periodically? I had no choice but to go w/ an open system because of strict codes around here. The EKO would have had to have been ASME approved to pass as a closed system.

Thanks again.

 

[Eric Johnson]

The EKOs and other gasifiers are run as open systems in Europe, I believe. That's probably one reason why there's no tapping on the EKO for a pressure relief valve or a temp/pressure gauge.

Virtually all OWBs and the Garn are open system designs and most are made of regular steel boiler plate. With the right water treatment, corrosion shouldn't be a problem. If you have any flat plate heat exchangers on an open system, however, they should be periodically inspected and flushed out, since open systems can accumulate more crud than pressurized ones.

My EKO is pressurized, by the way, and it works just like any other pressurized vessel. I know commerical installations in NYS need the ASME stamp, but there's no such restriction on residential installs that I am aware of. There certainly are plenty of pressurized, non-ASME wood-fired boilers working around here.

 

[Bob Rohr]

I'd wonder why you chose an open system? That boiler is built to be used as a pressurized heat source.

Rust never sleeps, ask Neil Young Yes there are corrosion inhibitor products to limit the effects of corrosion, but they need to be maintained, and replenished, at an ongoing cost.

I would recommend a closed loop piping system that allows the gas fired boiler to bypass the storage. Really no need to turn your easily stored chemical energy, gas or Lp, into hot water until it is needed.

hr

 

[GibsonGuy]

As I stated before, I really had no choice. There are pressurized systems w/ EKO's in the next county, but they wouldn't let me to do so. There are also units installed inside garages, but that doesn't fly here either. All I can figure is that there are plenty of seven figure homes in our resort area so the locals that aren't so fortunate pay the price from time to time. My open system works great, but I think we did a far too simplistic scheme. I was told, off-line, that I won't loose prime if I loose power if air is not allowed to get into the system. I'll do the schematic tonight. We're just getting some rain and it's supposed to turn to snow. Within an hour I'll have the rest of my firewood inside for the season.