Getting ready to go live this weekend with my EKO 60, Thermostat question

[mwk1000]

I am finally ready to get the heat coming. I have an EKO 60 feeding a DIY storage tank. The tank feeds two zones that are heat exchangers to my forced air propane furnaces. I was originally planning on adding 2 thermostats to control the zone pump and the fan motor in the furnace.

After thinking about it I was going to try to use my existing thermostats since they are 2 stage thermostats and "steal" stage 1 for the EKO. I would jumper W1 and W2 on the existing furnace controller so that if the thermostat calls for stage 2 it would initialize both stage 1 and 2 and essentially run on high. ( Basically what I would want for a backup to the EKO ). I would then take the stage 1 (W1 ) from the thermostat to my EKO Zone controller thermostat inputs to trigger the zone valve and the pump.

Has anyone done something similar ? See any problems with the plan ? It would save a lot of time and money in the wiring and thermostats as well as keep the existing walls nice looking with only the original thermostat. Not to mention no retraining of the spouse.

 

[Nofossil]

I think I understand what you're doing in a general sense. However, do you want the EKO zone running if the EKO and storage are cold? I'd assume that's when you'd hit stage 2 and kick in the backup.

I do a similar thing with 2 stage thermostats, except I use stage 1 when I'm heating direct from the EKO and stage 2 when I'm heating from storage. There's only a 2 degree difference the way I have them set up. Backup is a whole different story at a much lower temperature. My 'stats have an 'unoccupied' mode that hey can be forced into that I use when heating with my backup.

 

[mwk1000]

I think having the EKO ( Actually just the storage ) on would be OK in the case where it is not keeping up but I can see your point about letting it get to room temp. I am planning on using the EKO 99% of the time, the storage is big enough to carry me for a day at my coldest design temp ( -15). If something went wrong the storage would cold down to room temp and would essentially add no heat but I don't see it removing heat though I suppose it could have the unwanted effect of heating my storage with Propane ( Ouch !). It would waste energy circulating but if we were going away I would probably just flip the off switch on the storage. Unlike many of the designs I have seen here I am running my zones from the tank and the boiler is a separate loop that heats the tank.

I was a bit more curios about whether my planed approach would activate the fan or if I would need to add a jumper to the furnace controller to get it to come on. I'm not an HVAC wiz so I don't know if the thermostat activates the fan circuit or if the furnace controller does that when it sees the stage one circuit closed. I suspect the furnace controller does this and I will have to jumper the stage 1 to the fan control.

I don't have an unattended mode on mine, I also don't see them operating independently so if stage 2 is on so is stage 1 , ie. stage 1 is needed to activate the ignition sequence.

 

[mwk1000]

Just a follow-up for anyone interested in trying something similar. The thermostats ( White-rogers 1F8-261 ) turned out to be flexible enough to make it all work. To sum up:

I disconnected stage one from the furnace and rewired it to my Taco zone controller returning the common (Red to the furnace.

I jumpered the empty stage one terminal on the furnace to the stage two thermostat terminal on the furnace to be sure the the furnace would go thru the gas ignition sequence if stage two called for heat !

I flipped a small switch inside the thermostat to tell it to activate the fan immediately on thermostat closure ( Electric/Hydro mode ). This eliminated the need to jumper to the green ( Fan ) terminal.

It works well. Stage 1 is low fan ( 1200 CFM ) activates the pump and opens the valve from my storage tank. Since the furnace was designed for high efficiency to move lots of air and use low temps I was able to heat the house with tank temps at 110 and register temps at 95. That is the same as the gas stage one temps. As the tank temperature rises the heating is more immediate. I am seeing a 15* difference from the register to the tank as the temperature climbed.

In testing the backup, I raised the thermostat from 64 ( Day time away temp ) TO 68. Seeing the temperature was more the 3 degrees away from the 68 desired the thermostat called for stage 1 and 2 and the propane ignited and ran on high until 68 reached. From then on only stage one ( EKO Heat ) was used.

Alternately, I raised the temp from 68 to 71 and stage one ran for 10 min increasing the temp to 70 before stage 2 time limit was reached and stage 2 was called . ( Again firing up the propane and kicking the temp over the set point ).
Since my tank was only at 115 this was not to surprising, it will do much better when I hit normal operating temps of 170-140.

I will be taking some advice and working in some low temperature valves or relays to make sure the circulating pump is not powered unless the tank temps are good enough. Perhaps a aquastat relay in series after the Taco controller to ensure that the tank line is at 115 or better ? Cheap and simple.

 

[mwk1000]

Not quite ready for prime time with this.

I am having a very strange problem with my second thermostat/zone. When I wire the thermostat to the Taco Zone controller it has strange and negative effects on zone 1 It acts like the thermostat zones on the Taco ZC-403 are not independent. I am assuming at this point is has something to do with two many 24 volt transformers since one alone works perfectly but when I add the second the antics begin.


How do others activate the fan in your plenum heat exchangers from the EKO? I am getting by by jumping the thermostat connections from zone 1 over to zone 2 so both zone run together basically using one thermostat for both. But perhaps understanding how other are running would help. At this point I am not sure what a separate thermostat would do different. The way it is now is a bigger drain on my storage.

 

[stee6043]

I don't have all of the taco controls you have. I simply have a second thermostat conneted directly above my existing forced-air thermostat. I use the heating output of the new thermostat to trigger the cooling circuit on my existing thermostat. I throw the breaker on my A/C so the "new" thermostat only turns on the fan and not the fan/AC combo.

I also use a relay to run my HX Coil circ pump from the same signal for the furnace fan, via a second transformer. So when the thermostat turns on the fan it also runs my second circ pump which flows water through the HX in the plenum. My primary circ pump runs via the EKO controller.

This seemed like the most simple setup to me....

 

[rickh1001]

Sounds like you have a better handle on than I do, but here is how I hooked up my plenum HX's. I put an aquastat on the HX piping at the plenum. It closes on temp rise, and send current to the furnace fan. The thermostat goes to the Taco controller, which turns on the zone circ when there is a call for heat. The aquastat turns the furnace fan on when it is up to temp. If I were to use the oil burners themselves, they just operate normally, so the blower fans are turned on by either the oil furnace controller or by the hot water in the HX, or both, it wouldn't matter. This is a more expensive way to go I suppose, since you need additional aquastats, but it seems to work well. As I mentioned in another post, I also added an aquastat on my storage piping to control all power to the Taco zone controller itself, so that it won't circulate cold water through the HX's if I am away, and it is necessary for the oil burners to kick in (heaven forbid!).

 

[stee6043]

I am ultra cheap, my friend, that was my driver. I used 12" of thermostat wire to get the job done upstairs and not much more downstairs. Less is more for me! ha.