Looking for a control

Josh M.

I have a 100,000 sq/ft radiant job I am doing with 5 different temperatures. I have decided to use variable speed injection to mix. Also I am going to stage 4 boilers. Can any of you think of a control that does it all? Oh yeah it is all outdoor reset. Thanks guys!

Mark Hunt

4


Munchkins with the "Vision" control.

Mark H

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Gary_2

Boiler control

A Johnson Control DX9100 will do it. You can buy the control already programmed when you tell the supplier what you want it to do. The possibilities are endless. Relitively inexpensive.

Boilerpro_2

A couple of suggestions

If you are doing all outdoor reset, get a four stage boiler control with outdoor reset. Provide some type of return temp protection for the boilers (another variable speed pump or Esbe mixing valves). Then use manual three way valves to set a fixed flow of hot and return water to each zone to meet each temp need and viola, as the boiler water resets, so do all the supply temps to the zones. An added advantage is that the heating plant load is stabilized because the fixed three way valves limit how quickly the zone can pull heat off the boiler when starting cold. You could also use a series of tekmar 361 mixing controls, which also can provide indoor feedback, with a tekmar 254. Both can provide outdoor reset. Just make sure the 254 reset curve is set slightly higher than the highest curve of the 361 control requirements. Just some of my ideas.

Boilerpro

Steve Eayrs

I would go tekmar..

since you could do all you wanted, with the right combination of controls, and do everything.
Steve

Josh M.

Thanks guys.. All good suggestions however using a bunch of tekmars can be really difficult to write up an operations manual on. I am really just looking for one control to do it all. I do have a question for boiler pro though. How do you figure that the supply temp on the three way resets itself? Unless it is fully manual operation it will try and maintain a constant temp. Anyhow I am not a fan of float type or manual mixing valves when it comes to a project of this magnitude. But I am going to look into the Johnson control that might be the ticket. Again thanks guys I appreciate all of you input.

Mike Kraft

Josh

what BP is suggesting with 3 ways sounds very good.Once your highest temp is established and programmed in your curve,the four remaining will be mixed down manually.This doesnt mean that they wont benefit from modulation of reset........they will.Less controls,less wiring,less piping stradegy and a bit more econmical.

cheese

T. Barrett

Looking for Dunham 3/4\" Thermostatic Exp. Valve

I need a Dunham 3/4" thermostatic expansion valve. Anyone have one for sale? (email: trabar02@hotmail.com)

T. Barrett

Wayco Wayne_2

I've been looking at the Danfoss

control panels. I havent used them yet but it seems to me they have packages that include everything including controls for 1 through 7 zones, all packaged and ready to work. It might be worth looking into. WW

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Boilerpro_2

How it works, Josh

The mixing valves I was referring to do not have a temperature setting like those commonly used. They are simply a three port valve with no actuator and in the 1-1/4 inch size probably costs less than 50$. The mixed port goes out to the zone, one supply port goes some off to a tee on the return from the zone, and the other comes off the boiler. Sounds pretty typical. Now here's the neat part. Let's say you need 10 gpm out to the zone @140F on the coldest day. The zone operates at a 10 F delta tee. On that coldest day the boiler control curve is set to reach 180F. At the mixing valve you will have 130F water returning to be mixed with 180F boiler water. To get 140F out of the mixing valve at 10 gpm, you will need 8gpm of 130F return water mixing with 2 gpm of 180F water. So now set the mixing valve to provide this flow ratio. 80% from the return port and 20% from the supply port. Later that month with have a nice midwinter thaw and the outdoor temp is up at 40F. The boiler control resets the supply water temp to the whole system down to 118F (a typical reset ratio about 1.6). For that 10 gpm zone the reset supply requirement is now about 100F when its 40F outside. With the lighter load but same flow rate, the return would be about 96F. Now inside that fixed mixing valve we have: (zone return water) 96F x 8 gpm + (boiler water) 118F x 2 gpm = (zone supply water) 100.4F x 10 gpm. Pretty slick, eh. Another nice thing is if you are feeding remote zone manifolds from a single central heating plant, this zone would only require the supply and return piping to carry 2 gpm instead of 10 gpm. Nothing easier than running 1/2 inch to 3/4 inch pipe instead of 1-1/4 inch.

Boilerpro

Now on that same zone the supply port is recieving 2 gpm of 118F water and the return should be about
F (lighter load means less delta tee)

Boilerpro_2

How it works, Josh..... repost, minus the extras at the bottom

The mixing valves I was referring to do not have a temperature setting like those commonly used. They are simply a three port valve with no actuator and in the 1-1/4 inch size probably costs less than 50$. The mixed port goes out to the zone, one supply port goes some off to a tee on the return from the zone, and the other comes off the boiler. Sounds pretty typical. Now here's the neat part. Let's say you need 10 gpm out to the zone @140F on the coldest day. The zone operates at a 10 F delta tee. On that coldest day the boiler control curve is set to reach 180F. At the mixing valve you will have 130F water returning to be mixed with 180F boiler water. To get 140F out of the mixing valve at 10 gpm, you will need 8gpm of 130F return water mixing with 2 gpm of 180F water. So now set the mixing valve to provide this flow ratio. 80% from the return port and 20% from the supply port. Later that month with have a nice midwinter thaw and the outdoor temp is up at 40F. The boiler control resets the supply water temp to the whole system down to 118F (a typical reset ratio about 1.6). For that 10 gpm zone the reset supply requirement is now about 100F when its 40F outside. With the lighter load but same flow rate, the return would be about 96F. Now inside that fixed mixing valve we have: (zone return water) 96F x 8 gpm + (boiler water) 118F x 2 gpm = (zone supply water) 100.4F x 10 gpm. Pretty slick, eh. Another nice thing is if you are feeding remote zone manifolds from a single central heating plant, this zone would only require the supply and return piping to carry 2 gpm instead of 10 gpm. Nothing easier than running 1/2 inch to 3/4 inch pipe instead of 1-1/4 inch.

Boilerpro

RB_2

Does this fit your specifications?

These are availble for motors under 10 hp....

Let me know if you want more details.

RB

RB_2

Sample Load , Flow, Pipe Sizes & Velocity For Schematic Above

Just to give one an idea of typical loads and flows a project of this type may experiance.

The project engineer would generate a specific spreadsheet for the correct loads and areas based on his/her comfort in a variable delta t system...this is only to get one thinking about the electro-mechanical interface.

Boilerpro_2

Josh, only 2 different tekmar controls needed

The boiler staging control and a mixing control for each temp. IE. 1 - 254 four stage boiler control and 5 - 361 injection controls. Only two different instructions need to be written, only the settings change from each 361 to the next.

Boilerpro

tombig

Boilerpro

I love simple. It's an ideal way to circ. multiple temps. from a primary loop reset. I was mulling over a bypass valve set up, but a 3way manual would work. It must take some "observation time" to get your mix temps dialed in but once you're done, it's done. Absolutely beautiful in it's simplicity.


Tombig

Josh M.

Wow guys all of this stuff is great info. I do agree with the simple thing boiler pro. That is actually what I do with larger houses only I use four way mixing valves instead of three way because it gives me that little bit less head that I need for a smaller pump sometimes. I think I will definatly mix my returns for thermal shock protection. I guess the real reason behind variable speed injection is because there is so much piping that has to be done that I am going to use siggi's mini-tube concept to reduce the amount of distribution pipe. I am becoming a huge fan of variable speed injection these days though. I have cut my call backs in half because I don't have to go back and fine tune things once the house has been lived in for a while. That is important to me on this project because it is pretty far from my office. Again thanks guys. All of this is great info. I have been able to add a few new products to my arsenal! Not to mention I haven't really looked into munchkin boilers before and from what I can see they look great! I really like how everything is accessible in such a compact boiler!

Boilerpro_2

Tombig

Many manual three ways come with data on what the mixture proportions are at different settings. If you know what your temp needs are, you should be able to preset these pretty close if you have them piped so only the flow through that zone will effect the flowrates through the valve (ie. P/S). If the flow rate varies through the valve from what you design data calls for, ... ie. you're getting more flow through the zone than needed..., I believe that the proportional mix will be the same. This should yield the same average temp out in the system. I've found in my limited experience that if you can keep the supply temp within about 30 % above of what you need, you are OK.


Boilerpro