EKO 40 System Design Help

[jeffesonm]

I am immersing myself in the world of hydronic heating as I prepare to hookup the EKO 40. This is going in the basement of a 1800 sq ft 1957 ranch house... oil fired baseboard, interior three flue chimney, wood floors throughout entire house.

I've come up with a three phase plan for getting this all together... start basic, get experience using it, spread out the cost, etc. Over time I will add storage and then supplement baseboard with lower temp emitters as I renovate portions of the house.

Phase 1 - ASAP
Get boiler hooked up to existing system. Live with with some combination of more frequent loading, bigger temp swings in house, and some idling. Use wood stove in shoulder seasons and oil backup when gone for a few days. DHW via GeoSpring HPHWH.

Phase 2 - <1 year
Add 500-1000 gallons pressurized storage and enjoy less frequent/more convenient boiler firings, no idling, etc. Consider incorporating DHW.

Phase 3: 1-5 years out
Major house renovations... ~ 700 sq ft addition... master suite and combine/expand kitchen/great room. Install radiant under tile in kitchen, bathrooms and half of great room. Here is what that might look like... shaded areas are radiant. Details not important here, just mentioning what the long term plans are for the sake of future consideration.




Keeping all that in mind, I mapped out what I've got in place with the existing oil fired baseboard heating setup. I used the Taco circulator sizing guide and measured all the baseboard/piping/fittings in the two heating zones. Assumptions are delta T of 20 degrees and 500 btu/hr/ft for the 3/4" tube/fin baseboard.




Right now this is plumbed via two zone valves and one big, old circulator of unknown size... it is a 3 piece pump with a Sid Harvey 1/12 hp motor... yellow tag on flange/connection is unreadable.



Boiler fires when necessary to keep itself warm. When there's a call for heat from one of the thermostats, the zone valve opens and the circulator runs (generally followed by the boiler). Easy enough.

The EKO came with a Danfoss which I plan to use for return protection and a Taco 0010 F1 which I can use for whatever. I also have a bunch of 1 1/2" iron fittings/valves which I will use for close-to-boiler piping. Other piping will be copper because it's shiny and I like sweating pipes more than turning wrenches. For Phase 1 I'd like to get this plumbed in with a minimum of work/expense because it's cold out, the house is cold and I don't want to burn any more oil. I can fuss with stuff over the summer maybe as I'm stuffing giant propane tanks through a 30" basement door...

So my questions (so far) are...

• How do those calculations look? Does it matter that the one zone is way bigger than the other? Does that just mean the pump is oversized for the smaller zone, and if so, does that matter in any practical sense?
• Can I use one of the two heating zones as the dump zone, by T'ing in an automag to the supply and an extra return?
• Anything special I need to look for in a pressure relief valve? Boiler came with a 1 1/2" T with a 3/4" port sticking out that I plan to hook into for the valve. The BTU ratings on these are all over 500,000 BTU/hr which easily surpasses the boiler... something like this set to 30 psi do the trick?
• I'm still digesting the manifolds vs primary/secondary and zone vs circulator configurations... this part is giving me a headache... sooooo many options. Any advice on my particular situation, considering the three project phases?

 

[__dan]

Plan the EKO and the storage at the same time. You may save yourself some stress and hurt.

I'm not familiar enough with the EKO, but I'm assuming two things, it's not rated for condensate and not able to turndown the firing rate to match the load. With baseboard HW, the loads will go from all full to nothing in 20 minutes and 30 minutes later will call again for a little. The boiler can not go from a ripping fire at 100,000 btu to a small fire at 10,000 btu which is why storage is necessary.

Small fuel loads will not fix this if the boiler can not turn down the firing rate at from 3 or 4 to 1. It will burn the 1/2 load at 100,000 btu then go off.

I could be wrong about this and there may be users here who run the EKO without storage and let it idle (safety limit high temp off). More likely, idling will get you all the problems people complain about, fighting with their boiler. Since the boiler is not rated for condensate, idling will cause the smoke, tar, creosote to escape the boiler into the house wherever it can. Idling and condensate will make a mess.

The best design drawings for wood boilers I've seen are on the Tarm USA website.

Good luck, lots of EKO users here.

 

[maple1]

I also think there are some on here who use Eko without storage. Hopefully we'll hear from them. But I don't think I have heard of any, or certainly not many since I can't remember them, complaints about a big mess from idling. It will make creosote, whereas storage should eliminate it, but if you stay on top of it & regularly check for it, you should be OK.

Even if not doing storage now, proceed as if you are with the piping. It will be a lot easier to do later with a couple of valved-off stubs left at the right places. Maybe even a couple more valved stubs that you think you might need. Don't skimp on ball valves throughout especially since you're doing stages - isolating things when opening the system is golden.

If by dump zone you mean in the event of a power outage - I have a two storey, with my dump zone going to the upstairs zones. It convects around them good. If I also open up the valves to my first floor zones, it takes a while for them to get hot. So I wouldn't count on first floor zone flow to keep things cool in a power loss. Either some radiation directly above the boiler, or maybe also incorporate a UPS big enough to run one circ for as long as it would take for a full load to burn out.

Consider Alpha circulators. If you use one for your loads, you can tune the flows to meet most of your needs. It will ramp up & down as you throttle flow with valves. And they use less electricity. And they can work without being wired to your zone valves. When a zone valve opens, they sense the pressure diff & ramp themselves up.

Ordinary boiler PRV should work, yes 30 is a good number.

I zone with zone valves & one circ (an Alpha now if you couldn't tell). Wouldn't consider zoning by pumps. I went with a manifold rather than p/s - not sure it was the right thing to do and basically did it that way because I didn't know a whole lot about p/s & already had the manifolds in place. I also have plumbed so that water doesn't circ thru my backup source (electric boiler) when heating with wood, and also doesn't circ thru my storage when the backup is going, with a couple check valves.

Good luck - adventure awaits.

 

[mr.fixit]

I'm no plumbing expert, but there are others here that are,so if you can post a diagram or sketch it out on paper and take a picture of it,they may point you in the right direction.

On the running with no storage.
I always thought my eko idled reasonably well,provided the wood was dry. With no storage you will have to watch how much wood you put in and for sure have a overheat system working.
I have an aquastat on the supply out of the boiler that activates my largest zone at 200*F. I also have a UPS power supply running things in the event of a power failure.

 

[jeffesonm]

Thanks all for the input so far. I don't want to rehash the storage/no storage debate... plenty of threads that discuss the benefits of storage and limitations of running without it. I recognize the value and plan to add it, but I've got enough going on at the moment with the boiler install... it's cold out and I want to get it up and running.

If by dump zone you mean in the event of a power outage - I have a two storey, with my dump zone going to the upstairs zones. It convects around them good. If I also open up the valves to my first floor zones, it takes a while for them to get hot. So I wouldn't count on first floor zone flow to keep things cool in a power loss. Either some radiation directly above the boiler, or maybe also incorporate a UPS big enough to run one circ for as long as it would take for a full load to burn out.

Yes dump zone for power outage. As I understand it, power loss will kill the draft fans but you need someplace to dump excess heat while the fire continues to burn down/smolder. I was thinking Zone 2 since there are so few turns and it's ~24% of boiler output. Not much room to stash anything above the boiler and it's already right below my two zones. My current storage plan has the supply just a few inches above the boiler and probably 20' away, so not sure how much help that will be. I'd prefer something that doesn't require batteries/maintenance, but maybe I will add a UPS/circulator if Zone 2 thermosiphon action doesn't cut it. I assume the ultimate failure mode is the PRV pops... what then? A mess in the basement? Anything more catastrophic?

Consider Alpha circulators. If you use one for your loads, you can tune the flows to meet most of your needs. It will ramp up & down as you throttle flow with valves. And they use less electricity. And they can work without being wired to your zone valves. When a zone valve opens, they sense the pressure diff & ramp themselves up.

I have been looking at these and other variable speed pumps.. seems they have come down in price since 2008 when the P/S thread started. Still yet another set of calculations for pump/watt/savings payback period...

 

[maple1]

I assume the ultimate failure mode is the PRV pops... what then? A mess in the basement? Anything more catastrophic?

A mess, yes. What happens then depends. Do you have a well, or are you on municipal water? If on a well, then your water supply will be limited too with no power. Maybe 5 gallons in the pressure tank? Once the cold water stops coming in, things could get to boiling dry in the boiler. Then there could be all kinds of trouble. Could do in the boiler - worst case is somehow things get REALLY hot & start a fire & you lose your house. Such a setup would also rely on the fresh water feed stuff being open all the time. That's the way it likely should be anyway, but I (and others I think) like to keep it valved off to avoid a sudden large increase in system pressure from a malfunctioning or dirty pressure regulator on the infeed, or an endless supply of water leaking if a leak should develop somewhere..

My dump setup works pretty good, except when an air bubble that I didn't know was there makes it way into the zones when the NO valve opens. Discovered that one last month. So I'm going with even more redundancy & running my loading unit pump through a UPS. Got the UPS, just have to get it setup & wired. Redundancy can be a very good thing, 'cause even with the best of plans, crap still happens. An Alpha pump will run quite a while on a good size UPS - like <20w compared to 60w for a 15-58 on low.

 

[jeffesonm]

Thanks, that is helpful. I like redundancy. Any thoughts as to cast iron baseboard? Not much room for radiators in the basement above the boiler but I could squeeze some cast baseboard up there and it seems like radiating heat would dissipate better then tube/fin convection in an area without much airflow...

 

[Fred61]

it seems like radiating heat would dissipate better then tube/fin convection in an area without much airflow...

It makes it's own airflow if you allow some space above the fintube.

 

[jeffesonm]

Any feedback on my flow rate / head loss calculations? If I did all that math correctly, Zone 1 is way, way bigger than Zone 2. None of the smaller or variable speed pumps can achieve this flow/head and I would need something like a 009. Or I guess moving to primary/secondary piping I could use the existing oil boiler circulator for the zones and then use the 0010 and get another smaller pump for the oil boiler. Is it worth splitting Zone 1 in half to try and create 3 more balanced zones? Not sure why they ran 15' of baseboard through the closets on the right side of the house...