Advanced Thermostat Recommendation

ben_18

I have been using the Honeywell 8000 series REDLink thermostat to control the one-pipe steam of a 5 story 15 unit apartment building. I have 2 remote sensors on the 3rd floor and average the value.
It is not working so well. I would like it to turn on more often for less time. To get a better view of how it's running I wish I could monitor and have a log of the following data points.
-Temperature set points
-heat on/off
-temperature at each sensor

I am working on making a Python scripts to log into the thermostat web interface and collect this data once a minute but that is harder than I thought.

Any recommendations on a better Wifi Thermostat system that will give me this data?

ratio

One of the new 9000 series stats might be worth looking in to. In addition to a smaller rollout (RedLINK peripherals can be reused), Honeywell exposed the PID loop for manual tuning in one of the advanced setup screens. (NB: I have not fiddled with it yet, just noticed it's there.)

delta T

ben said:

I have been using the Honeywell 8000 series REDLink thermostat to control the one-pipe steam of a 5 story 15 unit apartment building. I have 2 remote sensors on the 3rd floor and average the value.
It is not working so well. I would like it to turn on more often for less time. To get a better view of how it's running I wish I could monitor and have a log of the following data points.
-Temperature set points
-heat on/off
-temperature at each sensor

I am working on making a Python scripts to log into the thermostat web interface and collect this data once a minute but that is harder than I thought.

Any recommendations on a better Wifi Thermostat system that will give me this data?

Agree with the 9000 series stat they are very nice. However, the first questions I would have is why? Running shorter cycles more often is not the best thing for your steam system. It will not help the uneven nature of the system, in fact, it may make it worse. You need a real steam expert to come in and check the venting on the mains and the rads to balance the system. This will be the best money spent for comfort and efficiency IMHO

ChrisJ

@ben
More cycles per hour will do what you want. More cycles and shorter run times.

But as I said in the other thread, you need main vents.

For Ben's other thread regarding this please see :
https://forum.heatinghelp.com/discussion/comment/1448698#Comment_1448698

delta T

ah, well oversized boiler will cause all sorts of problems. I see now, and second the main vents, it will make a difference!

ben_18

Thanks guys.
The main thing I want for now is to monitor the following:
-Temperature set points
-heat on/off
-temperature at each sensor
-decide which sensor controls thermostat

Once I have this data I can better diagnose the problems by experimenting with different options.

ben_18

@delta T I would rather not replace the boiler it is quite expensive. I have put much time into downfiring the two stage burner and even at the lowest setting it is oversized as discussed hereforum.heatinghelp.com/discussion/157847/high-and-low-fire-problem-of-webster-jb1c-07#latest
I am trying to run it the best I can with what I have...

ChrisJ

You know who might be able to help you a lot.
@PMJ

I think he's running something similar to what you're looking to do, including dealing with the oversized boiler.

PMJ, can you help?

delta T

Sounds like you are on the right path. I had no background with my initial comment, my apologies. I still think main vents will help you though....

delta T

You are definitely on the right path, I didn't have any of the background info when I made my initial post. I don't have a ton of experience with data monitoring, maybe @Mark Eatherton or @hot rod would have some insight?

PMJ

Ben,

As @ChrisJ says I run an oversize boiler and more cycles for less time each has been my solution for years. However, having a friend who is running one pipe steam in multiple unit apartments I know the issue you have is how to really know what is actually happening where under what conditions with limited or no access. As the operator in your own home it is easy. As a landlord really not so easy.

Very generally speaking, spreading the runs out does help. But it can be more problematic with one pipe systems as if they are quite unbalanced it takes completely filling some rads to fill others at all. So if you don't ever run to a pressure stop ( as I never do) you may never fill some rads. This is where your access issue to see what is really happening is a real problem.

Anyway, what are the specific issues you are trying to do better with? If you just want to try spreading the run time out some that isn't so tough.

ben_18

@PMJ It seems you have similar heating problems to mine.
The boiler runs maybe 15-20 minutes then it turns off on pressure and cycles every 5 minutes.
With the current honeywell stat and remoter sensors i am gettting it to run only a few times a day for over and hour each. I would like it to run more often for less time to making the heating more even. This way the tenants wont complain and i can lower the setting from 76 and save some on heating.
Previously I was using a heat timer which ran every hour but was hard to control and overheating the building.

KC_Jones

The heatimer does exactly what you are trying to do. If it was me I would have learned how to use and adjust it to get the results I wanted. There aren't any thermostats that will control the run time like you want, that's not what they are designed for.
Also you seem to be ignoring the very solid advice about venting. You are worried about fuel cost? Lack of venting is most likely costing you tons of money. You are essentially burning fuel to not heat the building. You need to address the venting, until you do everything else is futile.

ben_18

Yes but the heat timer controls are in the building and the super controls it.
How important is venting if the boiler is oversized double what it needs?
Also, if I put main venting in will I need to resize the air vents on all the radiators? This is an apartment building and i only have limited access to the units.

KC_Jones

Ok now I'm confused, who owns this building? The venting is always important even more so with an oversized boiler.

Jamie Hall

ben said:

Yes but the heat timer controls are in the building and the super controls it.
How important is venting if the boiler is oversized double what it needs?
Also, if I put main venting in will I need to resize the air vents on all the radiators? This is an apartment building and i only have limited access to the units.

Don't even think about how you are trying to control the heat until you get the venting right. As I have said before, the best controls in the world are of no use until the venting and piping are made right.

And no, you may not have to resize the air vents on the radiators -- although it might not hurt.

BobC

All you can do is try and convince the owners about the fuel (and money) they are wasting. If they don't agree I'd start looking for a new place to live.

If the venting is bad and / or the pressure too high no boiler control is going to make a difference.

Bob

PMJ

ben said:

@PMJ It seems you have similar heating problems to mine.
The boiler runs maybe 15-20 minutes then it turns off on pressure and cycles every 5 minutes.
With the current honeywell stat and remoter sensors i am gettting it to run only a few times a day for over and hour each. I would like it to run more often for less time to making the heating more even. This way the tenants wont complain and i can lower the setting from 76 and save some on heating.
Previously I was using a heat timer which ran every hour but was hard to control and overheating the building.

Ben,

What you describe is what I had when I moved in. The oversize boiler ran a while and then began to cycle on pressure until the tstat was finally satisfied and then the temp overshot because the rads got much fuller in the process than needed for the conditions due to the time lag to warm up the stat. My system is two pipe and the mains were adequately vented back then to run the conventional way.

From what I am hearing, simply spreading out your run time as you wish to probably will help with this. It is the way I started. Figure out what the worst case overall on percentage you need for the coldest day is. For me it is 50%. So the first thing I did was take 30 minutes run time and divide it into 3 10 minute on/10 minute off segments for each hour. To do this simply you need to get a delay on/ delay off timer relay that you put in series with the current call for heat line to the burner. Both times on and off need to be independently adjustable. So whenever the Tstat is calling for heat, this relay will cycle the boiler on and off evenly, fill the rads more slowly, and there will be less overshooting.

Since the day I started this cycling approach I have never shut off on pressure again. My vaporstat is now only a safety device. By spreading out the run time in shorter bursts you will never build any pressure. Pressure only builds as radiators actually fill. They never need to be close to full to heat on average days. It is very possible to run even very oversize boilers without ever building any pressure by cycling them evenly.

Having said all that, two cautions:

As I said earlier if your one pipe system is so unbalanced that some rads don't currently fill at all until after others have completely filled then this approach will likely end up that those straggler rads never will fill. Rads do need to be reasonably balanced for this to work well in any system. That was easy in my two pipe system and having 100% access as the live in owner. So if you are very unbalanced now anywhere that will be a problem.

Secondly, just doing this by itself will delay the initial response time from a long off period from where you are now. I did end up adding a preheat sensor to run longer on any call for heat when the mains were cold. After than I went to a PLC platform to add other features but I did run a couple years just with the relay timer and with just that overshooting was improved a lot. But you need a timer relay with two adjustment dials so you can adjust the on and the off times independently.

ben_18

@PMJ This seems like a really good idea. What is the model of time delay relay that you used?

The problem is that the building is 1.5 hours away from where i live so if it doesn't work well it will be hard to fix.
It's a 1-pipe and it has no main vents.

It will cost a nice amount, and require many hours of my time to get estimates and get main vents installed with little guarantee of savings. And it might throw off the whole apartment building and all the radiators would need to be rebalanced.

I used to have a dream of balancing the apartment building but because it has 15 units and i don't have free access it seems like it will be very hard to do.
I am just sticking to the steam heating in my house and trying to balance it.

PMJ

ben said:

@PMJ This seems like a really good idea. What is the model of time delay relay that you used?

I have used one of these before: http://www.macromatic.com/literature/catalog/time-delay-relays/#?page=22

Repeat cycle, independently adjustable times for on and off whenever the stat is calling for heat. The 24 volt signal that was directly powering the boiler control now powers the coil of this relay. You take the same hot 24 volt signal from the relay coil thru the cycling relay contacts and then to the boiler control. It simply starts and stops the boiler in cycles of your choosing during a continuous call for heat from the thermostat. Simply put, you are extending the time from call to satisfaction because the radiators fill more gradually and you end up with less overshooting.

Remember, your total % on time must be enough to heat on the coldest day. So start with plenty of extra on time and back down from there just by turning the two knobs. Maybe even start with one cycle per hour but limit the run to say 45 min and then go off for 15. Once this thing is in there you can have as many cycles per hour you want at any on/off duration you want during each call for heat.

Also remember what I mentioned before. Recovery from long off periods will be slower with this unless you add a preheat sensor on the mains. I still found it better though and ran with just the timer relay for several seasons. Also, if things are really unbalanced and some rads don't ever get any steam until many others are full with vents closed then this approach may cause those late filling rads to never get anything except near the very end of a very long call for heat. Round numbers I think any system needs to be balanced such that the first and last radiators to get new steam do so within a minute of each other. Once you have that the rest is easy and this approach is really a very effective way to achieve very low pressure operation - even with a very oversized boiler. But as others have said, main venting changes might be required to get things even enough. Your situation not being able to check what is happening at all the rads may make this tough.

1-1/2 hours away sounds like a lot to monitor things. But then it appears you have added controls and done some of this already.
Hope this helps.