VisionPro 8000 settings

ChrisJ

So, I decided to buy a used VisionPro 8000 as I got a good price on one.  Seems to work great and was easy to setup.



However either 1 CPH simply doesn't agree with me or my system, or I'm not waiting long enough for things to settle down.  With my mercury style T87F I had the anticipator set somewhere between 1.1 and 1.0 and she ran pretty decent.  Never saw any pressure build, all radiators would heat in enough time and the system would shut down in 10-15 minutes.



With the Visionpro 8000 set to 1 CPH all hell breaks loose.  Air vents start clicking due to steam actually getting to them, I start to build some pressure, over 0.5PSI which I have never seen before and all of this to maintain temperature which ends up overshooting by a lot anyway?  I need 3-4 sections of my rads hot not all 20 and instead im getting the full package deal right now :).



Does the VP have to go through some kind of learning curve or do I just need to go to 2 CPH?

My reason for going to the VP was I like the accurate feel and control of a digital thermostat.  I also like to know when its on or off which was only possible with the ring off of the T87F.

ChrisJ

overshoot

Ok I'm not so sure it overshoots at all with 1CPH.

However the house does seem to cool down too much for my taste and the system just runs way too hard trying to catch back up.  Is 2 CPH considered acceptable with steam and large tube radiators?  When set to 1 CPH all of my rads are pretty much cold by the time she fires back up.

Jamie Hall

As with so many of these things...

the answer is "maybe".  Experiment a bit with your VisionPro and see if you can get it to work the way you want it to; there is no commandment that says it has to be set at 1 cph for steam.  If 2 works better, go for it..



They are alleged to have a learning function, so it probably will pay to make the change and wait a few days... got to admit I can't see it working in the ones in the place I supervise, but then we never change anything here anyway!

Long Beach Ed

Vsion Pro

We've had pretty good results with them.  Personally, I wish I could refine the settings better, to 1.2 or 1.4, but most of our customers tolerate the 1 cph for steam and learn to live with a bit of a temperature swing. 



As said, no reason you can't use 2 cph.  And perhaps the thing does "learn" and adjust to moderate the settings, though I doubt it does.  The learning perhaps only adjusts the stat time on setback recovery. 



The longer cycle time should improve efficiency.  At least we tell the customers that. 

Mark N

How Long?

How long did the boiler run on a call for heat with the Vision Pro? How many cycles did you observe? Did you install this tstat on Wednesday when it was down to like 10 degrees in New Jersey? A cold day like that will cause the boiler to run longer and build pressure. You say the boiler was running 10 to 15 minutes with the T87 that sounds kind of short should be more like 20 minutes.

ChrisJ

Thursday

Didn't get the t-stat until Thursday when it started warming up here.



With the T87F I still wasn't seeing longer than a 15 minute cycle even when it was 10F out the other night. With the anticipator off (1.2) I was seeing 25-30 minute run times on cool days but the system was starting almost ice cold every time.



In reality, perhaps my run cycles were a bit short with the anticipator set to around 1.0. The thing I liked was all of the rads stayed pretty hot. It was like the system was always on. I have no idea what effect this had on our heating bill,but it sure felt nice.



With the VisionPro set to 2 CPH so far I'm happy with the performance, however its been warm out today so not much of a test. Did not measure cycle length with it on 1 CPH, however they were quite long even though it was only 20-25F outside.



I'm going to continue testing and watching it.

David Nadle

CPH

My experience with this thermostat is that the CPH setting won't limit run time. You are not likely to see any difference in performance with CPH=2.



If your system is usually quiet but long cycles cause hissing vents, all I can say is welcome to the club. I've tried many things over the years, including CPH=2. 

ChrisJ

No

Long run times and hissing vents has not been normal.

Interestingly it has not done it since I set it to 2 cph. I have no doubt this could be pure coincidence. I increased the vent rate on the radiator in the room with the thermostat and things have calmed down. When I had started messing with the T87F's anticipator I had slowed this radiator down to try and make the system run longer with more anticipator.



So it sounds like the CPH setting on the visionpro 8000 is nothing more than a lockout? It doesn't change anything else other than it won't let the system run more then X amount of times in an hour?



What is the big benefit of the 8000 with steam then? The recovery mode?

gerry gill

it does change the run time.

i use one on my mini tube system and found that a cycle rate of 6 works better than 1..so of course i use 6...if 2 or 3 works better on your system, then by all means, use what works for your system.

ChrisJ

mini tube

Gerry,



Out of curiosity are you running a setback with the mini tube?

gerry gill

could, but no

the wife and me like it warm so we keep it set at a given temp..

David Nadle

amplification

I wasn't perfectly clear. CPH is not a simple lockout, and it will change the "normal" runtime, but it won't limit the runtime. CPH is a factor in the Honeywell P+I algorithm, it has an effect similar to changing the anticipator in a traditional thermostat. If, due to setback use or very cold weather, it takes much longer than normal to satisfy the thermostat, the thermostat is not going to force your runtime to end early to stick to the CPH setting. At least that's what I've seen.

ChrisJ

run time

Is there a way for the visionpro to display system runtime?  I had a Hunter thermostat from around 2004 which had this feature and I'd love to be able to display the runtime.  This is of course would not take tripping due to pressure into consideration but I'm not worried about that at this time as it has not happened yet.



I have been running the system set to 1 CPH for a few days now after tweaking my venting.  I'm really curious which actually uses more fuel, 1 CPH or 2 CPH.  The system cools off almost completely in between cycles when it is set to 1 CPH, at least this is the case when it is in the mid 20s to 30s outside.  2 CPH things maintain some heat.

Jean-David Beyer

I have a Honeywell thermostat that does that.

But it has been discontinued for years. It records the hours and minutes it has been calling for heat today, for yesterday, and for the entire time since I last reset it. I reset it once a year on September 1.



But that is not how long the boiler was firing, because it is a modulating boiler with outdoor reset. So it adjusts its firing rate to match the load implied by the outdoor temperature and what zones are running. And it does not modulate down far enough, so sometimes it cycles off even though the thermostat is still calling for heat until it runs the boiler temperature down low enough to cause it to fire again. So even if you could find one, you could fool yourself.



Instead of looking for a thermostat like that, get a gas meter with a usb socket on it and run that into your computer. ;-)

haaljo

Also noticed much "closer" temperature control at CPH 2

Got rid of setback as well. Internal customers are pleased.

We have a natural gas boiler. NG is the equivalent of $1.50 gallon heating oil. Quite a change from a few years ago.

I have a mercury stat as well (in parrallel) just in case the fancy vision pro fails.

crash2009

Chris,

 go get one of those Lascar data loggers.

ChrisJ

Lascar

Crash.



Was looking into that, which model did you go with?

Abracadabra

temp logger

I've used an Exetech temp logger.  Works real well.  I checked out the Lascar and it only allows 30 min intervals. I wanted something closer to 5 minute intervals.  Exetech does down to 30s intervals with 30,000 data points

Mike Kusiak_2

This Lascar

This is the remote thermocouple logger that both Crash and I use for cycling measurements by placing the probe in the flue pipe. You can sample down to 1 sec intervals.



http://www.testequipmentdepot.com/lascar/dataloggers/elusbtc.htm



also use the Extech loggers for room temp and humidity, but prefer the Lascar display software.

nicholas bonham-carter

data loggers

these look very interesting, and could give hours of "quiet time" in front of the screen.

if you measure room temperature instead of radiator surface temperature, then there will be some variables which are difficult to account for. they would be more scientific than my plates of butter method.

http://www.heatinghelp.com/forum-thread/138705/more-venting-another-rad-and-or-bigger-pipe

they would allow many here to arrive at the nirvana of simultaneous steam arrival.  --nbc

crash2009

Logger model

I got the less expensive model EL-USB-TC. 

crash2009

Good for open window detector

Yes, they are a great way to waste some time.  I enjoy trying to interperate every blip on the graph.  It shows LWCO events, VSTAT trips, clothes dryer running, hot water heater, the one I like the most is "tenant leaving window open at the same time every day".



I printed the graph and presented it to the tenant. This is how normal looks, this is how it looks with that window open, If you want to pay X dollars more for your rent, leave the window open all winter and I will just bill you. 



My point is there are some practical applications besides knowing how many minutes the boiler runs or stops for.

crash2009

Mike, I just noticed

 your picture on the left.  Thats a fine example of tenant leaving window open.

ChrisJ

LWCO

Crash, how often does your LWCO trip during normal operation?



I just programmed the thermostat with a 2 degree setback and I'm going to see how it goes in the morning. I have a feeling if anything, I'm going to run low on water. If a 2 degree setback works I may go further and see what happens.

crash2009

Not to often now

 I gave the boiler an extra half inch of water.  Added more main vents to help get my condensate back quicker.  and finally got the anticipator set correctly.  the open window was killing me too.

ChrisJ

open window

Did they say why they kept opening it?

crash2009

yes

but I was probably not listening.  Is there a good reason to leave a window wide open and go off to work? 

Abracadabra

yes? no!

"but I was probably not listening."







LOL!

ChrisJ

setback

Well I think this mornings setback was a success.

I went with 67F all night and then 69F in the morning and I slept well all night and woke to a nice warm house.  I did have a bit of an overshoot, ended up at 71F when all was said and done.  Not sure if the thermostat will "learn" to compensate for that or not with its adaptive recovery?





Might try dropping it to 66F at night next.

Mike Kusiak_2

Monitoring the system

Yes, I can see how an open window would cause a graph just like that. Is the thermostat located in or near his apartment?



Actually that particular one is is showing recovery from a deep setback at a church. Thermostat setpoint changed from 50F to 70F at 6 AM, where the long burn begins. 70F is finally reached at about 10 AM.



Second graph shows maintaining 50F during the week when the building is unoccupied.



I found some cheap thermocouples which can be permanently mounted at strategic points in the system. Typically use a stainless hose clamp to mount the sensing junction to the pipe and cover with insulation. Then you can just plug each thermocouple in to the logger to monitor that point.



http://www.ebay.com/itm/K-Thermocouple-Probe-50-250-C-1M-thermometer-sens-/250855147361?pt=LH_DefaultDomain_0&hash=item3a6821c761

crash2009

Near

The open window directly affects the thermostat.  Did you want to jump out of here for a minute?  http://www.heatinghelp.com/forum-thread/138952/Mike-Anticipator-Settings

ChrisJ

setbacks and cycles

Was able to do a 3 degree setback without cycling on pressure.  I tried using 2 CPH yesterday and last night for a bit and found I did not like how the system was behaving.



Even with 17F temperatures I was seeing 10 minute run times.  I set it back to 1 CPH and got my long 20+ minute run times back. While the system heated fine set to 2 CPH I feel it heats just as well on 1 CPH and probably runs more efficient.



It was 8F this morning and for the first time I had many Hoffman 1A's clicking.  I saw 0.5PSI just before the system shut down.  It seems like my system will slowly creep up to 0.5PSI and then it doesn't really go any higher and when it does it ends up dropping back down.  I still haven't seen it go any higher than in the picture at the top of this thread. 



Can't wait to see what it does at -19F.

Mark N

Confused

In your first post you state that with the T87 your boiler would run 10 to 15 minutes and you were happy with that. So you set the VisionPro to CPH=2 and you got 10 minute run times and you were unhappy.

ChrisJ

confused

Mark,

Sorry for the confusion. While 10 minute run times and more than one cycle per hour maintained the temperature fine I'm trying to gain more efficiency.  After listening to what others including yourself had to say regarding CPH and run times my understanding is a good long 20+ minute run time is preferred when it comes to efficiency.



After watching how the VisionPro behaves on 1 CPH and even 2 CPH I have a feeling the T87F was costing me more money with the anticipator set the way I had it.  Once I increased the venting on the radiator in the same room as the VisionPro it began to behave really well even on 1 CPH. 

Mark N

Efficiency

Chris



In my mind there are 2 types of efficiency when your talking about steam heat. There's combustion efficiency and overall system efficiency. The system will be as efficient as it can be if the boiler is properly sized, the mains properly vented and insulated, the rads properly vented for even steam distribution and the water as clean as reasonably possible. Let me give you an example of what I mean. During the resent cold snap I observed my system getting steam to the end of the mains a little over 5 minutes after start up then run run for another 15 minutes. To me that is a 75% efficient cycle because 75% of the BTU's went to the rads. I observed cycles in more mild weather where it takes 10 minutes after start up to get the steam to the end of the mains and the boiler then runs another 10 minutes or so. In that scenario only about 50% of the BTU's got to the rads. In both cases I used the same amount of gas but the first one gave me more heat.

ChrisJ

understood

Mark,



So this means my system getting steam to the rads within 5 minutes and running a total of 10 minutes gives an overall efficiency of 50%.  So that is actual proof that 1 CPH is more efficient overall.

I never thought of it that way, thank you for explaining it differently.

Mark N

The Library

Have you ever read the article in the Library here on Heating Help titled "It's All in The Venting"? The info contained in that article is crucial to having a better understanding of steam heat. The article states that runs times shorter than 20 minutes generally waste fuel and give poor steam distribution. Dan restates this info in the LAOSH in the chapter with the same name. I've tried 2cph and have found it to be unsatisfactory for my needs since I have cast iron rads. If my system had convectors or baseboards that heat quicker the 2 or 3 cph setting might be more satisfactory.







The 1 cph setting

ChrisJ

Yes

I've read that in TLAOSH.



I did not have any problem with uneven heating with it set to 2 CPH. I'm going to revisit that chaper. No matter how many times I read TLAOSH and Greening steam I always seem to forget things.

Mark N

2 CPH

Didn't work for me only a few sections of the rads warm and on a mild day with the heat of for a long time it would run and turn off before any steam got to the rads, Then it would run again because non of the rads got hot.