Outdoor Reset

[Sparky]

Over the last 3 years I have been testing, tweaking and doing different things to my EC 100
First I finally got a good supply of dry wood -20% Second I got my baro damper settings correct, Third I did the chain turbulators (Wow I can clean the tubes in less than a half hour) I also installed a SS plate overlay on my nozzle. (I went with holes instead of a slot, I figured I could slot it if that didn't work) The boiler works great with it we will see if it protects the nozzle in time. I also started weighing my wood. I figured that any changes I made I need to know for sure if they were doing any good. So far so good. I have a 2400 sq ft 2 story house built in 2008, I have since blown in 6" of cellulose in attic and spray foamed the box sill and down 3' on basement walls. I'm avg. 165 lbs a day (good or bad?) As I get better at cleaning the tubes my flue temps have decreased low to mid 300s (good or bad?) I am considering doing the outdoor reset (continuous flow) for a couple of reasons. One I have radiant heat on the first floor and on sunny days (a great solar gain for me) my house is hot, by the time the radiant kicks on it too cold. Second is I use approx. 15 degrees of water from 7am to around 4pm when I refire again (any savings) I have basic baseboard on second floor (toe kick heater in 2nd fl bath) not sure how that will be affected. I believe it will cost me $700-$1,000 (will get into the equipment details later) to do this not sure if its worth the investment? I also love playing with my boiler and going on this site to see what others are doing. (my wife says I have a problem) Thanks for your input.

 

[TCaldwell]

Sparky, then a lot of us have a problem! From my experience odr will give a more even heat, making the house feel more comfortable. Typically and especially during the shoulder seasons you can run storage much lower, more flexibility for firing times. However it doesn't change your heat load, on a cold design day you will still need a relatively high mix temp as with a conventional system. 700 to 1000 is conservative, overall I'm glad I made the change

 

[Chris Hoskin]

sorry for the shameless plug, but I think this is just what you are looking for: (broken link removed to https://store.tarmusa.com/collections/lk-armatur-featured-products/products/lk110-smart-control) Because of your solar gain issue you may want to choose the LK120 or LK130 that also monitor room temp.

 

[Sparky]

Thanks Chris I just got off the phone with TCaldwell he gave me the same advice
I'm going to call them next week
Didn't see outdoor sensor in kit or how to do 2 stories with different type of heat and different temperatures?


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[JohnDolz]

Thanks Chris I just got off the phone with TCaldwell he gave me the same advice
I'm going to call them next week
Didn't see outdoor sensor in kit or how to do 2 stories with different type of heat and different temperatures?


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I would think you could use 2 ODR's controlling 2 separate mixing valves that would feed the different zones. I have my system use similar to that but my 2nd "zone" is DHW. All of my controls are built into my boiler which can then control 3 different mixing valves (2 heating zones + DHW) via 1 outdoor sensor.

 

[Sparky]

I'm calling tarm next week and hopefully they have a solution. I'm hoping 1 mixing valve but we will see I'll keep you posted
Thanks


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[JohnDolz]

I'm calling tarm next week and hopefully they have a solution. I'm hoping 1 mixing valve but we will see I'll keep you posted
Thanks


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I am definitely not an expert and don't know the various solutions out there but if you want to use very low flow temps then you will need the zone get get heat almost 24x7. So if you have 2 zones that need 2 different water temps I would think you would need 2 mixing valves. That being said I have 1 mixing valve that is feeding 5 zones. I use the lowest possible flow temp that will meet the need of the 5 zones and then use thermostats to "fine tune" for each zone. Good luck!

 

[Sparky]

Hey Chris, When I read your post from my phone I didn't realize you were from Tarm. So I have a question. If I have radiant on my first floor and I like it 73 degrees. I have baseboard on my second floor and I like it 70 degrees. Can I do this with one reset mixing valve controller?

 

[JohnDolz]

Hey Chris, When I read your post from my phone I didn't realize you were from Tarm. So I have a question. If I have radiant on my first floor and I like it 73 degrees. I have baseboard on my second floor and I like it 70 degrees. Can I do this with one reset mixing valve controller?

It is not so much what temperature you would like the rooms to be but more a question of what design temp you need to get you there. I think your challenge is that your radiant floor will want much lower temp water than your baseboards. 1 mixing valve will create 1 temp water, I believe you will need 2. I was chatting with a guy at a local nursery and if my memory serves me he said he always runs the same temp through the radiant floor, regardless of outside temp, otherwise the floor is too hot to walk on. If that is the case I would think that you could use 1 Outdoor reset tied to a mixing valve and the another mixing valve from there that would feed that radiant floor at a fixed water temp. Like I said I am definitely no expert but I have a couple years of experience playing with ODR with 2 mixing valves feeding 5 zones plus DHW with 3 different types of emitters, With TCaldwell's help I think we have a system that is working pretty well and fairly efficient. You are welcome to pick what little is in my brain any time or feel free to come have a look.

 

[Sparky]

Tom is a pretty smart guy
Talking with him on Friday had my small brain spinning
But after doing some reading this weekend he started making sense
But one thought I did have is when I'm doing the odr I will always be running off storage. Now if my house is calling for heat it goes to the house first with a little going to storage but I should never have a call for heat (at least not a high temp heat) right?


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[JohnDolz]

Tom is a pretty smart guy
Talking with him on Friday had my small brain spinning
But after doing some reading this weekend he started making sense
But one thought I did have is when I'm doing the odr I will always be running off storage. Now if my house is calling for heat it goes to the house first with a little going to storage but I should never have a call for heat (at least not a high temp heat) right?


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I would need to see the piping going in and out of your storage to give you a useful answer. It sounds like you are plumbed as a 2-pipe storage system, if this is correct the mixing valve will be placed in the pipe that is flowing water to your zones. It will call for less hot water to the zones and send more to your storage when the boiler is running (mixing in return water to hit the target design temp). In my house I have things set so 3 out of my 5 zones call almost 24x7 - I use the thermostats to accommodate the solar effect as the sun moves and hits different zones throughout the day. If my house is at temperature I am usually running 120 - 135 degree design temp when it is below 35 out. I actually have a setback feature so I let me house cool down 5 or 6 degrees at night. My system also has an indoor sensor so when I want my house to start recovering the Indoor sensor sees that the design temp set by ODR will not do the job (very hard to recover with low design temps) so the Indoor Sensor overrides ODR. Even then I am usually below 150 degrees, except for those low single digit and below zero days. Can't say I ever remember seeing above 160......and yes he is a very smart guy.

 

[TCaldwell]

If your supply currently comes from your storage at 150 or above you probably won't have a call from the secondary boiler unless your design day has been exceeded with a exceptionally cold day. As John says he only gets near that water temp when he is recovering from a nighttime setback. You'd be surprised what a constant circulation of low temp water will heat, for me it's usually between 120 and 138 throughout the course of a day.
The the outdoor reset controller/valve is the one Chris sent you the link about. If you were to put a odr valve from your storage and you have a radiant mix valve downstream, the odr will dictate the radiant temp and the radiant mix valve will act as a high temp limit. If you plumb your radiant mix zone upstream of the odr mix valve you will have a more consistent floor temp. This might not matter, dependant on the room.

 

[Sparky]

Here is what I'm thinking, I set the design temp for the second floor baseboard, then the first floor with radiant will be a little hotter than needed, but will be tempered down by the manual tempering valve already installed in the system? I pretty sure I am going with the LK130 from Tarm it has the outdoor sensor and the indoor sensor. I think I have how I'm going to install it figured out, But as I stated before now if there is flow from my boiler and my house needs it it goes straight to the zones. But now I will always be running from and feeding storage? I believe I can install this so I can resort back to the way it is now. (if in design stage my house gets cold) I don't want Mrs. Sparky to get upset, she already thinks I have an obsession with my boiler

 

[TCaldwell]

You will be feeding the lk130 from storage on the hot side of the 130, the cold supply on the 130 will be a leg from your zone return and the design mix will be your new zone supply. For instance today my storage is currently 155, outside temp is 48 calling for a design temp of 109. If I was using a 3way valve most of hot supply water from storage would be closed off, staying in storag, the cooler return water would be returning to the boiler for reheat. Not sure if this answers your question
As far smarts, I just followed John on odr, I was skeptical but after seeing his in action, it makes sense!

 

[TCaldwell]

Mts sparky should be fine, as you will have indoor feedback to bump up the mix temp when needed. You will notice the baseboard will be much quieter and the temp more even, happy wife, happy life!

 

[Sparky]

Well I'm going to give ODR a try. I ordered the parts today from Tarm (they are close by) (NH) so I should see them tomorrow or Wednesday maybe have it installed by weekend
Will keep you posted


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[JohnDolz]

Great, good luck! I am not familiar with the Tarm ODR but I do have an ODR in my propane boiler that I think works the same way. I found the predetermined (based on emitter type) Design curve to be too narrow and too high.My wood boiler controls my mixing valve via what they call a "Slope for flow temperature" (see link to Product manual - look at the Effecta Lamda). Look for the page with the graphs and you will get a sense for how far out you can stretch the Design curve (I believe you will be able to do this by setting the endpoints of your line). You can also get a sense of how low you might try running the temp. You will then be able to shift the line up or down as needed. This is how my ODR on my propane boiler works and based on the quick read I did of the Tarm I am pretty sure it works the same way.
(broken link removed to http://www.effecta.se/en/downloads?folder=Product%2Bmanuals)

 

[TCaldwell]

Congrats, you will see odr is pretty intuitive once you get up and running, keep us posted.

 

[mark cline]

Just a thought here , my house is all in floor radiant . Would an outdoor reset be able to control pump speed with a Grundfos variable speed pump? I will install hardwood flooring over my radiant tubing and don't want the water temp too high. I would like to keep the water temp. constant at about 110F.

 

[Bad LP]

Are you using engineered flooring or solid? Remember RFH does not like to be covered up by a lot of wood or rug. I was taught not to go above 110. So that should be your high limit for the coldest of days days. I prefer my tile areas over my mahogany any day of the week. There is some really nice tiles being produced these days. Much more than 10 years ago when I built my house.

My mixing and ODR programing is done with a Taco radiant floor mixing block. The balance of the house is HWBB for now. My boiler is stupid.

 

[velvetfoot]

Here is what I'm thinking, I set the design temp for the second floor baseboard, then the first floor with radiant will be a little hotter than needed, but will be tempered down by the manual tempering valve already installed in the system? I pretty sure I am going with the LK130 from Tarm it has the outdoor sensor and the indoor sensor. I think I have how I'm going to install it figured out, But as I stated before now if there is flow from my boiler and my house needs it it goes straight to the zones. But now I will always be running from and feeding storage? I believe I can install this so I can resort back to the way it is now. (if in design stage my house gets cold) I don't want Mrs. Sparky to get upset, she already thinks I have an obsession with my boiler

To me, it your plan sounds like the mix valve is modulating the temperature on a pipe at the top of the tank, normally based on flow out of the tank. This pipe can see flow in both directions: going into the tank when the boiler is running and going out of the tank when the tank is heating the house. When the boiler is running in your setup, it seems that the zones would get first crack at the high temperature water coming out of the boiler, and then it would got to the normal outlet of the mix valve. Then, since the temperature of the water where the ODR is sensing is so high (compared to what the ODR is specifying on its curve), all the hot water would get diverted around the tank and back to the boiler. I think this is how the mix valve would work in reverse, no? Then, the boiler would start to get too hot since the tank was unavailable to absorb excess heat.

It all depends on how it's piped up, I guess. Maybe put the mix valve in a new parallel line and use check valves to control the flow direction?

I like the idea of using that same mix valve to meter how much heat is going into storage so you don't have such a cold return temperature to the boiler, and you're not robbing volume by recircing it around the boiler via the protection valve. I tried something similar but failed.

Another thought is that if the pump is running a lot you'll be using more electricity so you want efficiency there.

 

[Chris Hoskin]

sorry, all, I haven't checked in for a couple of days. Looks like everyone has this nailed down pretty well, thanks. I guess if it was me, I'd use the LK130 to control supply temp to the radiant zone(s) only and leave the baseboard zones alone. (yes, you would need two LK110/120/130 to supply two different supply temp needs). In peak heating season you will need as high a temp as you can get to the baseboards and in the shoulder seasons, where ODR becomes more important with high temp emitters, you are running off of storage more so you would tend to supply lower temps to the baseboard zone(s) by default anyway. Great discussion, thanks guys.

 

[Sparky]

That is what I am in the process of doing. I have baseboard on second floor and radiant on first. What I'm go to try to accomplish is setting the odr to second floor (water will be too hot for 1st floor. So I will temper that water w the manual value already in place. I will keep you posted to see how I make out. It's 3/4 installed now hopefully up and running by weekend I'm using the LK130 to do this


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[JohnDolz]

sorry, all, I haven't checked in for a couple of days. Looks like everyone has this nailed down pretty well, thanks. I guess if it was me, I'd use the LK130 to control supply temp to the radiant zone(s) only and leave the baseboard zones alone. (yes, you would need two LK110/120/130 to supply two different supply temp needs). In peak heating season you will need as high a temp as you can get to the baseboards and in the shoulder seasons, where ODR becomes more important with high temp emitters, you are running off of storage more so you would tend to supply lower temps to the baseboard zone(s) by default anyway. Great discussion, thanks guys.

Chris - I may have misunderstood what you were saying but I can tell you that I leverage my ODR all year long and run very low temp water through my "high temp emitters", even during "peak winter". Of course to make this work the zones are calling almost 24x7. As Velvetfoot points out, it takes electricy to do this but with the Alpha's + solar his is not something I factor in.

 

[TCaldwell]

I have 5 zones of regular fin tube, one zone dual pipe fin tube and one radiant zone, all controlled by the same odr temp. The radiant is controlled by a 3 way mix valve at the zone set to 120. Basically all zones get the odr temp, however when that exceeds 120, the 3 way mix valve at the radiant zone acts as a high limit for that zone only. This seems to work well for me.