DIY hydronic heating installation - Page 5

opiesche · 10-09-12, 04:29 PM

Quote:

Originally Posted by Mikesolar

Like this?

Danfoss Heating - North America

These 24vac motors will drive with any signal. I would think one of the guys could come up with an outdoor reset control that uses the PID control I saw on here. tekmar has one but it is more fun to make it.

That seems to be exactly what I'm looking for! I might be able to drive this directly from the Raspberry Pi's GPIO, with a little protection circuit in between - I'm not sure how they determine direction, since there's only one signal wire. The data sheet doesn't provide much insight, how does one change actuation direction through the input signal?

Mikesolar · 10-09-12, 06:30 PM

Quote:

Originally Posted by opiesche

That seems to be exactly what I'm looking for! I might be able to drive this directly from the Raspberry Pi's GPIO, with a little protection circuit in between - I'm not sure how they determine direction, since there's only one signal wire. The data sheet doesn't provide much insight, how does one change actuation direction through the input signal?

There are a number of different models but a couple of them are 0-10vdc so if you can provide a 0-10v signal as a proportion of an outdoor temp or as a comparison between two temps such as an outdoor temp and a supply to the floor temp, you could make it work. Other models have a 0v and a +24 and a -24v wire which is controlled through a SPDP relay which your control can turn on or off, using the output temp as a goal.

Just a thought.

opiesche · 10-09-12, 08:45 PM

Quote:

Originally Posted by Mikesolar

There are a number of different models but a couple of them are 0-10vdc so if you can provide a 0-10v signal as a proportion of an outdoor temp or as a comparison between two temps such as an outdoor temp and a supply to the floor temp, you could make it work. Other models have a 0v and a +24 and a -24v wire which is controlled through a SPDP relay which your control can turn on or off, using the output temp as a goal.

Just a thought.

OK, I think I get it. Floating actuators take a continuous control signal 0-n V, where 0 means closed and n means all the way open. Turn off the current, and the valve closes.

Then there's modulating actuators, can't figure out what that means or how they're controlled.

The third are the ones controlled with a relay - probably two control wires, one ground, and depending on which side the +24V are connected to, the valve rotates towards open or closed as long as the current is on. From what I see, most of them also deliver a proportional voltage as feedback that I could read the current valve opening position from.

Am I understanding correctly?

What I want is definitely one of the third kind described above - use DT relay to put voltage on either lead to open or close as long as current flows. This will be the easiest to control.

Based on that, do you think something like this would work?

VC8711ZZ11 - Honeywell VC8711ZZ11 - Two position, Low Volt Actuator for VC Series Valves, w/ end switch

I'm just looking to see if I can find something that fits the bill, but doesn't end up costing me $600

Thanks for all the information!

Mikesolar · 10-09-12, 08:56 PM

Quote:

Originally Posted by opiesche

OK, I think I get it. Floating actuators take a continuous control signal 0-n V, where 0 means closed and n means all the way open. Turn off the current, and the valve closes.

Then there's modulating actuators, can't figure out what that means or how they're controlled.

The third are the ones controlled with a relay - probably two control wires, one ground, and depending on which side the +24V are connected to, the valve rotates towards open or closed as long as the current is on. From what I see, most of them also deliver a proportional voltage as feedback that I could read the current valve opening position from.

Am I understanding correctly?

What I want is definitely one of the third kind described above - use DT relay to put voltage on either lead to open or close as long as current flows. This will be the easiest to control.

Based on that, do you think something like this would work?

VC8711ZZ11 - Honeywell VC8711ZZ11 - Two position, Low Volt Actuator for VC Series Valves, w/ end switch

I'm just looking to see if I can find something that fits the bill, but doesn't end up costing me $600

Thanks for all the information!

Thats a good beastie. I've used the 3 way ones ( with 0-10vdc) and they are good products. The price as shown is just the actuator and you will have to add the valve but together the price is pretty reasonable.

opiesche · 11-14-12, 03:10 AM

Hi all,

I haven't had much time to collect information and post it here, but I haven't been completely idle. The manifold is hooked up, the old furnace removed, and I've had a bit of a hard time (understatement of the century!) in getting the system filled and working with the new water heater.

Here's the story of the last few days:
Adventures in home improvement: Oh dear God

Long story short, there's some bad luck, probably some bad decisions, and a faulty water heater involved in creating what I can only call prime sitcom material. I figured instead of only reporting on what worked, I should also post about the complete disasters and failures, so that's what the wordy post I linked to is all about.

Hope this helps someone avoid similar problems!

opiesche · 12-23-12, 10:24 PM

Another quick update: The system is up and running, and working well for the past 5 weeks or so. We've had one unusually cold period (28F for a few hours one night), at which the system had a little trouble keeping interior temperatures at the target 71 degrees, but I'm confident that problem will disappear once I've got insulation between my floor joists - as it stands, I've definitely got a higher R value on top of my heating loops than below, which of course can't be good.
Other than that, the heat is very comfortable and the natural gas usage seems to be only about half what it was with the forced air, based on preliminary usage data from PG&E. I'm looking forward to getting the crawlspace insulated to bring the system up to its true potential

AC_Hacker · 11-27-13, 11:34 AM

Quote:

Originally Posted by opiesche

I'm looking forward to getting the crawlspace insulated to bring the system up to its true potential

opiesche,

I'm not too far from doing a radiant floor of my own, so I'd like to ask a few questions...

Did you measure and record what the feed temperatures were to your radiant floor before and after you insulated under the floors? I don't fully recall what kind of setup you had, but as I remember, there was a gas water heater that you used for heating... I don't know if you set the water heater to some working temperature, and controlled the house temp by cycling the pump to the water heater or what?

So, did you see a dramatic change after insulating?

I know that Vlad had a system that would inject pulses of water heater water into the circulatory flow as required, and he was able to monitor what the temperature of the input flow was. I thought there might be something equivalent with your setup, even though as I write this, there probably is not.

The plan I am working on is to use a very similar construction method as you used, with the exceptions that I intend to put some high-load styrofoam insulation directly under the aluminum plates, and instead of using OSB over the plates, I'm planning on using tile backer board, which has a higher U-value (lower R-value) than OSB.

Do you have any thoughts or suggestions as to my intended approach?

Lastly, I think that your Raspberry Pi temp logger is brilliant, and I intend to build one also. I'll likely be asking lots of questions as the time approaches...

Best,

-AC_Hacker

opiesche · 01-02-14, 05:05 PM

Hey AC_Hacker - sorry for the delay in replying, I didn't get an email notification for your post.

I didn't measure the temperatures before and after insulating, but it's noticeable by feel. I just bought rolls of faced fiberglass insulation, cut them into ~6ft batts for easier handling, and stuffed them paper up into the joist cavities. Afterwards, the floor was noticeably warmer, and I was actually able to reduce supply temperature a little bit.

My system has a fixed supply temperature (right around 98F) from a standard gas tank heater, and the Pi controller only turns the pump on and off after doing temp measurements and prediction of future temperatures and lag of the system, which works pretty well. It measures temps every 60 seconds, calculates heat loss, measures how long it takes for temps to change when the pump is switched, and predicts fairly accurately how long ahead of time it needs to switch the pump to keep the temp at target.
I've got the code for it on github, so if you're interested, take a look (https://github.com/opiesche/Prometheus). It should work with any Pi, although I've only tested it on a model B, with the Raspbian distro from the Raspberry Pi foundation.

Happy building! This was one of the most rewarding projects I've done - it's a lot of work, but it's certainly worth it in the end!

opiesche · 01-02-14, 05:14 PM

Missed your point on the styrofoam! I didn't know there was EPS that was able to take the load of an entire floor on top, that's certainly a great idea. In the end, you'll obviously want to have as much R below and as little as possible above the loops, and foam directly under the loops should be pretty awesome.
Are you planning on putting hardwood floor on top of it? What sort of underlayment were you thinking of?

AC_Hacker · 01-02-14, 07:20 PM

Quote:

Originally Posted by opiesche

Missed your point on the styrofoam! I didn't know there was EPS that was able to take the load of an entire floor on top, that's certainly a great idea.

Yeah, it's been the quest for the holy grail for me. I used some Dow Corning XPS in the wall of my kitchen called Formular 150... sounds like it would be 150 psi, but no, its 15 psi. Then I found some stuff called HILOAD 50 that is actually 50 psi, and I think it can work. I found some here in town and it's 2" thick ($75 for 4'x8'x2"), so that means I'll have to slice it into many 3/4" strips. We do have to suffer for our obsessions.

Quote:

Originally Posted by opiesche

In the end, you'll obviously want to have as much R below and as little as possible above the loops, and foam directly under the loops should be pretty awesome.

That's my plan. The foam will give me about R4 below... and then I'll go after the under floor insulation, too.

Quote:

Originally Posted by opiesche

Are you planning on putting hardwood floor on top of it? What sort of underlayment were you thinking of?

I'm gonna put linoleum on top of the floor... But before I pull out my cash, I'm going to investigate sheet steel.

Above the plates, I've decided to go with Hardy-board, its a concrete & paper manufactured material. I've done some comparative thermal tests, and it is better than wood. However, if there wasn't a dissimilar-metal issue, I'd be tempted to put steel right on top of the plates. Now there's some low-R material.

I've been watching some wacky UK remodeling videos and it's making me think all kinds of crazy thoughts!

Your work with the RaspberryPi could come in very handy.

-AC

11-14-12, 03:10 AM	#45
opiesche Helper EcoRenovator Join Date: Jul 2012 Location: Rohnert Park, CA Posts: 99 Thanks: 4 Thanked 14 Times in 9 Posts	Hi all, I haven't had much time to collect information and post it here, but I haven't been completely idle. The manifold is hooked up, the old furnace removed, and I've had a bit of a hard time (understatement of the century!) in getting the system filled and working with the new water heater. Here's the story of the last few days: Adventures in home improvement: Oh dear God Long story short, there's some bad luck, probably some bad decisions, and a faulty water heater involved in creating what I can only call prime sitcom material. I figured instead of only reporting on what worked, I should also post about the complete disasters and failures, so that's what the wordy post I linked to is all about. Hope this helps someone avoid similar problems!

12-23-12, 10:24 PM	#46
opiesche Helper EcoRenovator Join Date: Jul 2012 Location: Rohnert Park, CA Posts: 99 Thanks: 4 Thanked 14 Times in 9 Posts	Another quick update: The system is up and running, and working well for the past 5 weeks or so. We've had one unusually cold period (28F for a few hours one night), at which the system had a little trouble keeping interior temperatures at the target 71 degrees, but I'm confident that problem will disappear once I've got insulation between my floor joists - as it stands, I've definitely got a higher R value on top of my heating loops than below, which of course can't be good. Other than that, the heat is very comfortable and the natural gas usage seems to be only about half what it was with the forced air, based on preliminary usage data from PG&E. I'm looking forward to getting the crawlspace insulated to bring the system up to its true potential

01-02-14, 05:05 PM	#48
opiesche Helper EcoRenovator Join Date: Jul 2012 Location: Rohnert Park, CA Posts: 99 Thanks: 4 Thanked 14 Times in 9 Posts	Hey AC_Hacker - sorry for the delay in replying, I didn't get an email notification for your post. I didn't measure the temperatures before and after insulating, but it's noticeable by feel. I just bought rolls of faced fiberglass insulation, cut them into ~6ft batts for easier handling, and stuffed them paper up into the joist cavities. Afterwards, the floor was noticeably warmer, and I was actually able to reduce supply temperature a little bit. My system has a fixed supply temperature (right around 98F) from a standard gas tank heater, and the Pi controller only turns the pump on and off after doing temp measurements and prediction of future temperatures and lag of the system, which works pretty well. It measures temps every 60 seconds, calculates heat loss, measures how long it takes for temps to change when the pump is switched, and predicts fairly accurately how long ahead of time it needs to switch the pump to keep the temp at target. I've got the code for it on github, so if you're interested, take a look (https://github.com/opiesche/Prometheus). It should work with any Pi, although I've only tested it on a model B, with the Raspbian distro from the Raspberry Pi foundation. Happy building! This was one of the most rewarding projects I've done - it's a lot of work, but it's certainly worth it in the end!

01-02-14, 05:14 PM	#49
opiesche Helper EcoRenovator Join Date: Jul 2012 Location: Rohnert Park, CA Posts: 99 Thanks: 4 Thanked 14 Times in 9 Posts	Missed your point on the styrofoam! I didn't know there was EPS that was able to take the load of an entire floor on top, that's certainly a great idea. In the end, you'll obviously want to have as much R below and as little as possible above the loops, and foam directly under the loops should be pretty awesome. Are you planning on putting hardwood floor on top of it? What sort of underlayment were you thinking of?