New t-stats .. optional "system type" settings

Reply

  #1  
Old 11-18-12, 11:12 AM
Member
Thread Starter
Join Date: Jan 2009
Location: Northwestern Ontario (Canada)
Posts: 549
Received 1 Vote on 1 Post
New t-stats .. optional "system type" settings

I recently picked up 6 UPM THM303a thermostats on ebay for our in-floor heating.

(neat little units that also have Humidity readings (and can control a humidifier)..

One of the option settings on them is "System Type", that controls the "Cycles per hour".
Hydronic Heat / Condensing Gas .. 2 cycles
Commercial Unit .. 3 cycles
Gas or Oil Forced Air .. 5 cycles
Electric Heat .. 7 cycles
Also a 'disabled' mode that I assume uses however many cycles per hour is required to maintain +/- 1deg ?

Ive never had a stat with this setting.. other than wear and tear on the zone valves, is there any advantage to various settings ??
 
Sponsored Links
  #2  
Old 11-18-12, 12:36 PM
hvactechfw's Avatar
Member
Join Date: Jan 2011
Posts: 6,245
Received 0 Votes on 0 Posts
the smaller the number the longer the run cycle and typically the more comfort. For radiant heat you want a low number.
 
  #3  
Old 11-18-12, 03:02 PM
Member
Thread Starter
Join Date: Jan 2009
Location: Northwestern Ontario (Canada)
Posts: 549
Received 1 Vote on 1 Post
So the stat has to overshoot the temp by some calculated amount.. do these stats 'learn' to some extent ? Nothing said on the package or manual bragging about smarts..
 
  #4  
Old 11-18-12, 03:31 PM
NJT's Avatar
NJT
NJT is offline
Member
Join Date: Oct 2006
Location: USA
Posts: 23,539
Received 2 Votes on 2 Posts
do these stats 'learn' to some extent ? Nothing said on the package or manual bragging about smarts..
I believe that some do... at least as far as the 'anticipator' setting goes. I'm pretty sure that my older Honeywell (with no specific anticipator setting) does 'learn' after a period of time how to set the anticipator for minimum overshoot.

I arrived at this conclusion after observing my old system operation after hooking up the circulator 'post purge' circuit. It did seem to know that more heat would be coming 'after the fact' and always cut off the heat call before the room reached temperature. (which it did always reach temperature with the pump purging the heat from the boiler)

BUT then, neither does this thermostat have a 'cycles per hour' setting.

[ afterthought: It probably DOES have a CPH setting, but it's not apparent, at least they don't call it that and spell it out. I think that almost all digitals DO have a 'system type' setting. This setting probably carries a CPH setting with it but not specifically spelled out in the manual or on the setup screens. ]
 

Last edited by NJT; 11-18-12 at 04:19 PM.
  #5  
Old 11-18-12, 03:34 PM
NJT's Avatar
NJT
NJT is offline
Member
Join Date: Oct 2006
Location: USA
Posts: 23,539
Received 2 Votes on 2 Posts
Honeywell says this about cycle rate:

Q: What is a cycle rate?

A: Every heating system type will deliver heat to the house at a slightly different rate. Some thermostats provide you with the flexibility to set the cycle rate adjustment to match your specific heating system, whether it is gas or oil forced air, high efficiency forced air, electric forced air, or baseboard hot water.

A cycle rate is the ideal number of times a heating system will run, in an hour, to maintain temperature within one degree. For instance, gas or oil forced air systems have a recommended cycle rate of 6. With a cycle rate of 6, the heating system, at a 50% load, will cycle 6 times per hour. This breaks down to about 5 minutes on and 5 minutes off. Again, the actual on and off time of the heating system will vary as the load on the heating system varies.
 
  #6  
Old 11-18-12, 03:37 PM
hvactechfw's Avatar
Member
Join Date: Jan 2011
Posts: 6,245
Received 0 Votes on 0 Posts
I have no idea if they learn anything. They are not standard thermostats. They are made in Canada, I believe. Contact the manufacturer.

I doubt they overshoot the temp. More likely that the tolerance is tighter.
 
  #7  
Old 11-21-12, 07:15 PM
Member
Thread Starter
Join Date: Jan 2009
Location: Northwestern Ontario (Canada)
Posts: 549
Received 1 Vote on 1 Post
"Again, the actual on and off time of the heating system will vary as the load on the heating system varies."

So the "CPH" is really just an anticipator setting ? Changing the CPH setting really just alters the 'self-heat' function of the anticipator ? The number of cycles is just an example of typical system run periods, but has nothing to do with the actual operation in a given setting.

Now, Im set at the lowest CPH setting (2) .. which should be the least 'heat' for anticipation right ? If Im overshooting temp, then I should increase the CPH setting.
 
  #8  
Old 11-22-12, 09:14 AM
NJT's Avatar
NJT
NJT is offline
Member
Join Date: Oct 2006
Location: USA
Posts: 23,539
Received 2 Votes on 2 Posts
I'm afraid I don't have a real answer for you because I don't fully understand the CPH logic myself!

It doesn't make sense to me... I mean, let's say you set it at 2 CPH. Heat call comes and is satisfied, but it is a VERY COLD AND WINDY NIGHT, and 10 minutes after heat call ends, thermostat needs heat again...

Is the thermostat going to sit and wait until a half hour is up before firing the boiler again? That wouldn't be too cool... wait... it would be TOO COOL, maybe even COLD!

I see that you use 'quotes' around the word 'self-heat' and am sure you are using analogy and know that the digital t'stats don't use an actual heating element... that it's all done electronically...

But perhaps your analogy is correct, that the CPH relates somehow to the anticipator setting of old, in a digital sort of way.

If Im overshooting temp, then I should increase the CPH setting.
I think so... but that's the best answer I can give!
 
  #9  
Old 11-23-12, 10:06 AM
Member
Join Date: Jan 2008
Location: Southeastern Pennsylvania
Posts: 2,947
Received 0 Votes on 0 Posts
I have no idea if they learn anything. ...


Hey guys just thought you might get a kick out of this. I was reading a book about the Brain and Consciousness and the writer making a point said:


“My thermostat is conscious. It either thinks it too hot, or too cold, or just right”.

Now I feel next time when one of my thermostats dies I have to have some kind of ceremony.LOL



 
  #10  
Old 11-23-12, 03:27 PM
NJT's Avatar
NJT
NJT is offline
Member
Join Date: Oct 2006
Location: USA
Posts: 23,539
Received 2 Votes on 2 Posts
I have to have some kind of ceremony
Cremation by Acetylene sounds about right to me... either that, or test the question:

"Will It Blend?"

Consciousness does not imply possession of a soul though. No Soul, No Ceremony!
 
  #11  
Old 11-23-12, 06:43 PM
Member
Join Date: Jan 2008
Location: Southeastern Pennsylvania
Posts: 2,947
Received 0 Votes on 0 Posts
HaHaHa Trooper!

Right again Trooper. I never thought of cremation! And that point about No Soul, No Ceremony will save me some bucks.
 
Reply

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread
Display Modes
 
Ask a Question
Question Title:
Description:
Your question will be posted in: