| Author |
Message |
    
Jim Murphy
Citizen
Username: Jimmurphy
Post Number: 139
Registered: 5-2001
| | Posted on Monday, November 10, 2003 - 10:38 am: |     |
Hi all,
Looking to replace our old thermostat with a new setback version. Anyone have any recommendations? George? TJohn? Anyone else?
Gas-fired, one-pipe steam.
Jim |
jgberkeley
Supporter
Username: Jgberkeley
Post Number: 3289
Registered: 5-2001
| | Posted on Monday, November 10, 2003 - 11:40 am: | |
Yes, use the Honeywell CT3500 thermostat.
Go to the Honeywell website and search on CT3500 (no space) for details.
Just what you will need. |
Jim Murphy
Citizen
Username: Jimmurphy
Post Number: 140
Registered: 5-2001
| | Posted on Monday, November 10, 2003 - 11:49 am: | |
Thanks George! |
jgberkeley
Supporter
Username: Jgberkeley
Post Number: 3291
Registered: 5-2001
| | Posted on Monday, November 10, 2003 - 12:29 pm: | |
No problem. Is your old unit a 2 wire or a 3-4 wire?
This unit will work with both, you just need to keep track of the contact wires and the power wires. |
jrbell
Citizen
Username: Jrbell
Post Number: 12
Registered: 10-2003
| | Posted on Monday, November 10, 2003 - 12:54 pm: | |
A little thread drift here... We have two thermostats in our houss. This is a new (to us) home and we still haven't quite figured the things out (we aren't living there full time yet), but it looks like one controls the AC and another controls the furnace (forced hot air).
Is there any good reason why this would have been done? The thermostats are in separate rooms and I think I would rather have a single control panel... any thoughts? |
Jim Murphy
Citizen
Username: Jimmurphy
Post Number: 141
Registered: 5-2001
| | Posted on Monday, November 10, 2003 - 12:59 pm: | |
The old unit is a 4-wire operating in 2-wire mode. It actually has a clock that doesn't seem to work despite battery changes so somebody just disconnected one of the pairs of wire, rendering it incapable of "setting back".
It's pretty old-looking and partially inop so I figure now's as good a time to change it as any. Do you know where I can get the 3500? Does the dreaded Home Despot carry it or do I need to go to Palmer or Sears?
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Jim Murphy
Citizen
Username: Jimmurphy
Post Number: 142
Registered: 5-2001
| | Posted on Monday, November 10, 2003 - 1:37 pm: | |
Found this on the Utica Boilers website:
Q: My new steam boiler cycles very frequently, what could be wrong?
A: A new steam boiler could be short cycling due to a number of reason. The first may be something as simple as having installed a room thermostat that has an adjustable heat anticipator setting with in it. This setting needs to be at 1.2 for the longest cycle setting as possible allowed by the thermostat. The best thermostat for this is the standard Honeywell T87F round design unit that has this internal setting on the unit. The new digital thermostats of today are timed and many do not offer the option to give you a set point to satisfy the system requirements.
What do you make of this George? |
jgberkeley
Supporter
Username: Jgberkeley
Post Number: 3294
Registered: 5-2001
| | Posted on Monday, November 10, 2003 - 1:58 pm: | |
What do I make of it, the person is writing of cheapo digital units.
The CT3500 has the most advanced anticipator system on the market. It figures your house and changes the internal program daily to find the sweet spot, or the time it should turn on the heat to have your house toasty at wakeup time. That takes into account insulation, window or door leaks, and infiltration.
The one thing the TC3500 does not have is the ability to factor in the outside temperature changes. To do that you need to pay about $400 for a PC8900 home computer system. This unit has outside temperature and a set of inside and outside humidity sensors which track the outside of your house as well. Then the computer does the work. If you house takes 25 minutes to come to temperature when it is 50 outside, how long will it take when it is 25 outside? It then fires the boiler as needed and will adjust the program of under or over runs until it gets it correct.
Order them at Palmer, HD does not have them.
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Jim Murphy
Citizen
Username: Jimmurphy
Post Number: 143
Registered: 5-2001
| | Posted on Monday, November 10, 2003 - 2:01 pm: | |
OK. That's generally what I thought.
Thanks again. |
jgberkeley
Supporter
Username: Jgberkeley
Post Number: 3295
Registered: 5-2001
| | Posted on Monday, November 10, 2003 - 2:02 pm: | |
jrbell,
This is likely this way because the A/C installer just did not want to be bothered.
A new thermostat will handle both units. The Honeywell CT3500 is a good unit for that.
The PC8900 will even mix the two systems and use the A/C blower to curn and filter your house air while firing the heating unit, thus keeping the heat even room to room and saving on heating bills. |
1-2many
Citizen
Username: Wbg69
Post Number: 569
Registered: 6-2002
| | Posted on Monday, November 10, 2003 - 2:18 pm: | |
jrbell - when we moved into both our last and current homes, they each had heat but no air. we added central air, using a different thermostat. our installer told us, basically, the A/C thermostat is best placed by the A/C return, so that's where it wound up. also, in our current house, it's on the second floor, which is warmer than the first, so it also makes sense from that perspective to put the A/C controller there.
so, having been there and done that, that's why, just FYI. |
Master Plvmber
Citizen
Username: Master_plvmber
Post Number: 117
Registered: 3-2003
| | Posted on Monday, November 10, 2003 - 8:57 pm: | |
"The new digital thermostats of today are timed and many do not offer the option to give you a set point to satisfy the system requirements."
Jim Murphy,
The Utica Company is trying to convey the message that most other boiler manufacturers are saying also: Setback and steam are not a match made in heaven.
I'm sure even Mr. Berkeley will agree that the claim made by Honeywell of 33% energy savings using the CT3500 is far-fetched.
Steam is a slow-response system with little room for efficiency upgrades and set back is often self-defeating.
The logic in thermostats like the CT3500 is taken largely from the Tekmar Corporation of Canada. To get significant energy savings from this type of programming takes more information than a single wall-mounted interior unit can possibly gather.
Systems using outdoor sensors along with end-of-system monitors and room temperature units (thermistors) aim for an energy savings of 10-15% annually.
Perhaps it's that type of control Mr. Berkeley is talking about when he mentioned the PC8900. I've never installed that model.
I'm not bad-mouthing the 3500. It's a great thermostat for someone who has convinced themselves they must have setback.
The Honeywell T87F is and always has been an excellent unit built to last and work well with steam or hydronic heat.
Master_Plvmber
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NRL
Citizen
Username: Nrl
Post Number: 301
Registered: 8-2003
| | Posted on Monday, November 10, 2003 - 11:36 pm: | |
I just installed the HW 3500 and I see a remarkable difference in performance from the LUX and the mercury I had prior to the LUX. The steam system setting appears to be doing its thing. I am hoping to see efficiency gains but as Master P says, Steam heat is a slow response system. In either event the 3500 performs very well and we are please thus far with its performance. Spend the extra dough on a better thermostat. You wont have a LUX laying around collecting dust as I do now. |
sullymw
Citizen
Username: Sullymw
Post Number: 197
Registered: 5-2001
| | Posted on Tuesday, November 11, 2003 - 9:27 am: | |
I am a thermostat novice, but relatively handy. How can I determine whether the 3500 would be compatible with my system? I have a single-pipe gas fired steam system (converted from oil). I'm guessing you need more info about my current thermostat? Alas, I am at work. |
jgberkeley
Supporter
Username: Jgberkeley
Post Number: 3297
Registered: 5-2001
| | Posted on Tuesday, November 11, 2003 - 9:31 am: | |
You can look the specifications and uses up on the Honeywell website.
Or, just take it from me, the CT3500 will work for your system. |
jgberkeley
Supporter
Username: Jgberkeley
Post Number: 3298
Registered: 5-2001
| | Posted on Tuesday, November 11, 2003 - 10:34 am: | |
To setback or not to setback,
Two situations for my steam heat system:
First:
I set my thermostat to bring the house to 68 at 6 AM. I leave for work and have my thermostat set to lower the house to 55 during the day. My thermostat is set to bring the house up to 65 at 7 PM when I arrive home from work and then lowers it back to 55 at 10 PM when I go to sleep.
Second:
I set my thermostat to 68 and leave it all season.
Ok, I don't know about or support any claim of a 33% savings, but you guess which one of the above will reduce the amount of energy burned.
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Master Plvmber
Citizen
Username: Master_plvmber
Post Number: 118
Registered: 3-2003
| | Posted on Tuesday, November 11, 2003 - 6:52 pm: | |
You're running your heating system like a car on city roads.
Think of it like this. Which car is getting better fuel efficiency? The car ramping up and slowing down as it drives along city streets or the car that's cruising steadily down the highway at 55 MPH?
When your house cools down to 55 during the day it is losing all of the energy poured into it during that high 68 degree cycle in the morning.
Then it has to replace all of that energy when it comes back to reach 65. At 6:59pm everyday, your boiler water is as cold as the house it's in. Then your boiler must process a large number of BTUs to make steam, then send it through cold pipes to cold radiators sitting in cold rooms in a cold house. Then from 7pm to 10pm, it's trying to pit hot radiators against cold air, cold walls, floors, ceilings, chairs, tables and what ever else. Of course, the radiators always win, but at what cost.
It takes a tremendous amount of energy to meet this demand.
During my training in the Institute of Boilers and Radiation, we were shown that there are two ways to get the most efficiency out of a boiler. One way is never let it turn on (significant energy savings there!).
The other way is to never let it shut off (I'll explain). Boilers run at peak efficiency when they are at their hottest. An efficiency curve on a steam boiler looks like an inverted "L" during a run cycle that starts from cold.
Nearly none of the energy being consumed during the period that the burner comes on but before steam reaches the radiators is what you can consider usable energy (heat). It's not until steam is in the radiators that we can start to calculate any real efficiency.
It has always been, to my knowledge, an industry standard that setback on a residential steam system should never exceed 4 degrees.
I know that’s disappointing because people like fancy thermostats but that’s how it’s been presented to us in the trade for years.
Master_Plvmber
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jgberkeley
Supporter
Username: Jgberkeley
Post Number: 3306
Registered: 5-2001
| | Posted on Tuesday, November 11, 2003 - 7:17 pm: | |
OK, you win.
You must be the same bolier guy that runs the unit in my Mother-in-laws apartment. The heat runs full blast all the time. (Peak efficiency when it is hot)!
So she keeps the windows open.
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Master Plvmber
Citizen
Username: Master_plvmber
Post Number: 119
Registered: 3-2003
| | Posted on Tuesday, November 11, 2003 - 7:31 pm: | |
Ahh, the open window....
....original zoning device.
Master_Plvmber
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shoshannah
Citizen
Username: Shoshannah
Post Number: 299
Registered: 7-2002
| | Posted on Tuesday, November 11, 2003 - 8:23 pm: | |
The winter-long open window system has been perfected in the NYC prewar apartment. |
us2innj
Citizen
Username: Us2innj
Post Number: 892
Registered: 5-2001
| | Posted on Tuesday, November 11, 2003 - 10:33 pm: | |
MP, I totally understand your logic, and have run our programmable thermostat exactly as you discuss. The temperature range is 65 at its coolest and 70 when the heat is running. The only thing I notice is that when the heat turns off at 70, the steam boiler continues to generate heat so the house pops up to about 71-72 even after the system stops. |
Master Plvmber
Citizen
Username: Master_plvmber
Post Number: 120
Registered: 3-2003
| | Posted on Tuesday, November 11, 2003 - 11:10 pm: | |
That's where the anticipator is failing you. Either check your manual to adjust the setting or if it's a mechanical thermostat, you can check the amperage draw of the burner circuit and set the anticipator to that number.
Master_Plvmber
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newtoallthis
Citizen
Username: Newtoallthis
Post Number: 73
Registered: 2-2003
| | Posted on Wednesday, November 12, 2003 - 10:42 am: | |
Keep in mind that if you have a PSEG Worry Free contract, and the thermostat is old and not working properly, they will come out and replace it for you as part of the contract (they did it for us). |
Jim Murphy
Citizen
Username: Jimmurphy
Post Number: 144
Registered: 5-2001
| | Posted on Wednesday, November 12, 2003 - 11:31 am: | |
Just an update:
I bought the CT3500 on Monday night from Sears Hardware in Essex Green for $85.95. (Saw it last night at the Depot for $79.95 - doh!)
Installed quickly and is working like a charm. House is much more comfortable, although we do have an 8-degree setback applied as we are just too hot at night without it.
I had always heard about the pros and cons of a setback with steam. This discussion confirms that it is controversial.
Maybe a better approach is no setback with TRVs on the upstairs radiators.
Anyone care to weigh in on that approach?
Jim |
sullymw
Citizen
Username: Sullymw
Post Number: 198
Registered: 5-2001
| | Posted on Wednesday, November 12, 2003 - 11:32 am: | |
What did they install? Mine is old, but apparently working ok. I just want more features. Hmmmmmm....how can I make it break?  |
Master Plvmber
Citizen
Username: Master_plvmber
Post Number: 121
Registered: 3-2003
| | Posted on Thursday, November 13, 2003 - 8:19 am: | |
I love TRVs. When installed correctly, they have little or no effect on system balance and are the best way to give my customers the control they desire.
Actually, TRVs are for 2 pipe steam. Manufacturers of these valves are begining to use the term radiator thermostats when referring to the one-pipe control unit. It makes more sense since a radiator valve, be it mechanical or thermostatic, is a shutoff device used at the inlet.
Radiator Thermostats are what you probably need.
Master_Plvmber
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Yonti2323
Citizen
Username: Yonti2323
Post Number: 11
Registered: 6-2003
| | Posted on Thursday, November 13, 2003 - 3:11 pm: | |
I have a Honeywell thermostat located in the dining room, near the front door, and it works very well for the rooms nearest to it. However, the rooms upstairs don't get hot enough because the heat turns off before they can warm up sufficiently. Is there anything I can do about this?
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jgberkeley
Supporter
Username: Jgberkeley
Post Number: 3317
Registered: 5-2001
| | Posted on Thursday, November 13, 2003 - 4:00 pm: | |
If this is a single pipe steam system, yes. Change the vents on the radiators near the thermostat to cause them to heat last. |
Jim Murphy
Citizen
Username: Jimmurphy
Post Number: 145
Registered: 5-2001
| | Posted on Thursday, November 13, 2003 - 4:25 pm: | |
Also, check the heat anticipator on your thermostat. Modern steam systems are supposed to cycle less frequently but for longer periods. If the setting is too low, it will short-cycle and heat may not get to the far radiators. Setting should be at 1.0 to 1.2. It's found on a little wheel inside the thermostat.
Believe me, been there, done that.
Jim
Jim |
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