Cannot heat house and water in storage tanks at same time

[Northwoodsman]

Well,

I finally have my burn pretty fine tuned and BTU output from the EKO40 is great !

However, I have discovered that I am unable to heat up my (2) 500 gallon storage tanks if my Taco 007 pump (seconday loop feeding house) is operating.

Currently, I have been operating this seconday pump 24/7 so that the house radiant and baseboard pumps always have a good supply of hot water when needed.

Up until a few nights ago I have never seen my storage tanks above 155/160 F. However, I was "tweaking things" in the wee hours of the morning and accidently turned off the secondary pump and when I looked at the tanks in the morning they were both at 180 F.

This lead me to re-evaluate my plumbing layout to which I discovered the following:

1.) When the sencondary pump is operating and the water temp is less than 160 F, my Danfoss valve is closed/only partial opened. Thus, this causes my secondary loop to travel in a counter clockwise direction (UP through the tanks) at the same time my primary loop is traveling in a clockwise direction (DOWN through the tanks). Being as these 2 pumps are both 007's and the piping is all 1-1/4" copper, the 2 flows collide and thus I cannot heat my tanks to 180F.

2.) I originally plumbed the system as shown so that when the fire ran out in the EKO40 (after charging the tanks to 180 F and supplying the house with heat) and the circ pump on the EKO turns off (at 170/168 F), the secondary house loop would flow in a counter clockwise direction (UP through the tanks) as it was heating the house.

3.) In the meantime I have purchased an electric plug in timer that has 3 sets of programmable on/offs. I have plugged my secondary 007 pump into this timer and during the nightime burns (when we are sleeping and don't feel the slight temperature differences due to the pump being on and off) I turn the pump on for 1 hour and off for one hour 3 times (which takes me through a complete 5-6 hour EKO 40 burn). With this setup I have been able to get my tanks up to a much higher temperature than before. However, I'm not sure that this is the best way to do this (although it was very simple and inexpensive to install the timer).

4.) I have thought about turning my secondary pump on/off at the same time my radiant or baseboard pumps in the house itself are calling for heat but have run into a few problems/concerns if I do this:

* My baseboard system is controlled by normal 24V thermostats and Honeywell zone valves controlling 4 different zones.
* My radiant floor heat is controlled by a Heat Link brand 6 zone control module with an injection control system that keeps the incomming water temp that supplies the 4 different radiant (slow reacting) zone valves at a constant target temperature which is calculated by the controller and changes as the outside temperature changes.
* Thus, I am unsure of how to control the secondary 007 so that it will be on when either the baseboard or floor zones are calling for heat given that there are several different 110V and 24 V signals being outputted. I just received a copy of the injection controller manual and will study this to see if it can be used in conjunction with the 24V honey well zone valve signal to turn the 007 pump on as needed.



Thus, I am looking for suggestions on the best plumbing layout that would supply heat to the house while also putting the extra BTU's that the house does not use efficiently into the 1,000 gallon storage.

Any suggestions/comments are greatly appreciated.

NWM

 

[Nofossil]

Couple of things: It would likely help a lot to put a 140 degree element in the Danfoss. 160 is higher than necessary. You're on the right track as far as turning off the secondary circ if it's not needed. This layout also works best if primary flow is at least a bit greater than secondary flow.

 

[stee6043]

I have a very similar plumbing arrangement to yours. I started to play around with the flow through my HX loop a week or so back. My intent was to find out how big of a drop in supply/return I could acheive but I made an interesting discovery (which seems obvious to me now, after the fact). By slowing down/thorttling the circ on my HX loop (I also have two Taco 007's) I actually saw a big increase in how much water I had flowing into my tanks while the HX loop was active.

You may want to try using a light dimmer switch on your secondary circ pump to see if you can get to a point where you are still satisfying the heat load as well as putting some heat in the tanks. Just a thought....

 

[EricV]

Are 007 pumps needed for infloor and baseboard? Ifhe used 005's or 3 speed pumps would that help the flow to the primary loop?

 

[cvanhat]

i have the same exact set up as you except for i have only one 500 gallon storage tank and a eko 60. your problem is that the return from the house should be plumbed into one end of the 500 gallon tank, and then run a pipe from the opposte end of the 500 gallon tank into the danfoss. this way all return water has to be mixed in with your storage and actually warmed up before going to the danfoss. also my primary is run in 1 1/2 pipe, secondary is 1 1/4. this way water is always being forced into storage and is always going in one direction. my primary pump runs 24/7 and the secondary when the house thermostat calls for heat.

 

[Northwoodsman]

I spent a good deal of time yesterday making several adjustments and it appears as though last night I had a real good burn as my tanks went from 128/129 to 155/156 even with my secondary pump running all the time.

Yesterday I went on-line and looked at a smaller circ pump for my secondary. I found 003's but they were only available with bronze (expensive) construction on the particular web site on was on. Does Taco make a 003 pump they is cast iron? It looks like the 005 is smaller but I'm thinking that it may be too large for this application and really want to look at a 003.

I will pick up a dimmer switch today and hook it up tonight and see if I can slow the flow in my secondary loop down to a point where it still brings water from the tanks to the house but allows the primary pump to "WIN" with regards to dumping the extra heat intot he tanks. If this works I'm thinking I should probably just replace the pump with a smaller pump vs. using the dimmer switch all the time (is there any harm/in-efficiencies that I may have by using a dimmer swith on the pump).

Finally, I did find one major problem that I overlooked in the past. When I have no heat actuator (zone valve) on my Heat Link brand radiant floor heat manifold system I discovered that the water will run to that zone 24/7 (wide open) all the time. Thus, I had no actuator installed on the zone that goes to my upstairs rec room which is approx. 600 sq. ft. (I have noticed that for the past several weeks that room seemed awful warm eventhough I had no thermostat/heat actuator installed.) I was just thinking that since this room is above my breezeway (which is baseboard heat) that the heat was traveling up the stairs and keeping it warm.

Thus, yesterday I turned this zone completely off and now I will have quite a bit of BTU's that are not being used by this room (I plan to install a thermostat in this room in the near future).

Finally, last night I tried hooking up my heat link injection controller to a DPDT relay to turn this secondary pump off when there is no heat being called for by the house. However, when I tried to tap into the dry contact (by using the same single dry contact for both the propane boiler activation-which is currently shut off at both the power and gas valve- and the secondary pump activation) I had some wierd things going on with it. Eventhough my baseboard Honeywell zone relay was not wired into this circuit it would make a partial contact engagement when the heatlink system activated the dry contact for the propane boiler/secondary pump. I"m thinking that this is because I have one 24V transformer to which all my 24 volt signal's are being powered by (and possibly I am getting current leaking into the Honeywell relay due to this).

Thus, tonight I plan to install a new, separate 24V transformer that will only be used to power the dry contact for the secondary pump on my heat link 6 zone base module (I am going to use this contact instead of sharing the one on the injection controller with the propane boiler just to make sure that my signal is totally isolated from all others.)

Thanks for the help/feedback !

NWM

 

[chuck172]

cvanhat,

"return from the house should be plumbed into one end of the 500 gallon tank, and then run a pipe from the opposte end of the 500 gallon tank into the danfoss. this way all return water has to be mixed in with your storage and actually warmed up before going to the danfoss"

Pre-heating or in this case Re-heating the load return before it gets to the mixing valve may be a great idea. There are many problems are centered around the Termovar, Danfoss, mixing valves.

 

[stee6043]

I will pick up a dimmer switch today and hook it up tonight and see if I can slow the flow in my secondary loop down to a point where it still brings water from the tanks to the house but allows the primary pump to "WIN" with regards to dumping the extra heat intot he tanks. If this works I'm thinking I should probably just replace the pump with a smaller pump vs. using the dimmer switch all the time (is there any harm/in-efficiencies that I may have by using a dimmer swith on the pump).

NWM

North, I am of the same opinion as you regarding the dimmer. My intent is for it to be a temporary fix. This summer I plan to replace my 007 with either a much smaller pump or a multi-speed unit. I don't really like the dimmer approach for long term but it certainly works. For $13 it was an excellent investment and a great experiment...

 

[cvanhat]

cvanhat,

"return from the house should be plumbed into one end of the 500 gallon tank, and then run a pipe from the opposte end of the 500 gallon tank into the danfoss. this way all return water has to be mixed in with your storage and actually warmed up before going to the danfoss"

Pre-heating or in this case Re-heating the load return before it gets to the mixing valve may be a great idea. There are many problems are centered around the Termovar, Danfoss, mixing valves.

actually it does not have too much to do with the danfoss. this is how my dealer told me to install the storage into my system. i belive that the most important thing is to keep everything moving in one direction. i actually drilled two small holes in my danfoss thermostat so even if it were closed something would still flow through it.the whol idea of storage in my system is to eliminate fluctiations in temprature. we never let the eko burn out.

 

[Nofossil]

the whol idea of storage in my system is to eliminate fluctiations in temprature. we never let the eko burn out.

If that's your goal, then you will (or should) have flow through storage in both directions. Here's my analysis:

For this to work, the flow through the zones has to vary with heat load. If you have multiple zones that will happen more or less automatically. The colder it is, the more zones will likely be calling for heat at any time and the more flow you'll have through your zones.

Also, flow through the EKO has to vary with output. When the EKO is running flat out, the flow has to be higher than when it's down to coals. The Danfoss accomplishes this because it will recirculate more as the output drops, reducing the effective flow.

Finally, the EKO and load flows have to be balanced to at least some degree of correlation.

If the EKO is producing less heat than the zones need, then the flow through the EKO should be less than the flow through the zones. In that case, the balance of the zone flow should be drawn from storage, bottom-to-top.

If the EKO is providing more heat than the zones need, then flow through the EKO should be higher than the flow through the zones. The extra flow from the EKO should go through storage, top-to-bottom.

I'll mention that this is not how I operate. What I do is figure out about how many full-throttle burn hours I'll need in the next 24 hours. I'll look at my storage and see how long it's good for. At some point before storage runs out, I'll build a fire and run flat out until I've built up enough storage to last until a convenient time the following day. My average burn time is 6 or 7 hours per day, and I usually burn it in the evening. I let it go out cold when it's done, and it will sit for 18 hours until I need to build the next fire.

 

[kevindauch]

Hi Northwoodsman
In my system I have a Termovar valve placed just after the return from the load. When the return temp is above 160 it restricts the return flow to the boiler and puts the return water back to the supply before the Taco 007 circ on your diagram. That way when there is excess heat on the load, the excess is forced to the storage.