Thermostat that lets ME control the cycle rate?

On 4/8/18 11:23 AM, trader_4 wrote:

I explained what began this entire problem in another post earlier this eve.
It was intially a -boiler problem- (ok, I'll call it a boiler, though it doesn't "boil" anything, just heats water to about 150 degrees). It wouldn't start up properly. Plumbing/heating guy cleaned the (combined) ignitor/sensor rod and replaced the spark cable. He also replaced original thermostat (which had old-style "anticipator" with a "lever" to adjust it) with new thermostat (has DIP switches to set cycle rate). Old thermostat was -at least- 40 years old, perhaps older.
At first, that seemed ok, but then later in the day the boiler had startup problems again. After investigating myself (and some reading and researching), it seemed obivous (to me) that the problem was located in the "intermittent module" (Honeywell s86h) that was 30 years old (came with the boiler in 1988). I replaced it with a new Honeywell universal module that had my old one "on the list of units it replaced".
After I did this, the boiler now starts up with a proper ignition sequence, there are no more problems in the startup sequence that I've observed.
The problem I have now looks to be that the thermostat doesn't seem to be controlling the boiler as it should. It shuts it off prematurely. Or at least it appears that way to me.
This DOES NOT seem to be a problem related to over-temperature or with the aquastat assembly. Here's why I believe this to be so:
If I set the thermostat "way up high" -- say, 85+ degrees -- the boiler starts and runs, and KEEPS RUNNING without any problems until I manually shut it down by turning the thermostat "way down" to, say, 55 degrees. Then the boiler just "clicks off" as it should.
If there were over-temp or other faults, wouldn't the aquastat take care of that, and force a shutdown? It DOES NOT do this. Aquastat is set (as far as I can tell) at about 182-183 degrees.
I just had it running a short while ago. I have the old thermostat sitting near the new one, so I can observe the room temperature on both. They are within 2 degrees of each other (indicated temperature).
The indicated temp was about 66 degrees. I set the thermostat to 71 or so. Boiler comes on and runs. Ran for about 30 minutes, then the thermostat shut it off. But indicated temperature reads 68 degrees. I'm just guessing at the discrepancies in the needles.
I've changed the DIP switch settings from the 3CPH setting to 1CPH. I'll see if that changes anything.
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On 4/8/18 11:40 PM, J.Albert wrote:

Followup to my earlier post.
The thermostat I'm using is a Honeywell "round" model T87K1007.
I was using the DIP switch setting the manual recommended. That setting reads "High efficiency warm air (90%+), hot water, or heat pump (3CPH)"
That was causing problems -- boiler would start, run for a very few minutes, and shut off. The radiators wouldn't even begin to warm up. And it would repeat this at short intervals.
I changed the DIP switch setting to "Steam or gravity (1CPH)" to see if that would change things. And it DID -- it makes quite a difference. The boiler now starts, STAYS RUNNING until the radiators warm up, and then the thermostat shuts it off. The thermostat now keeps the boiler off until the radiators are cool, and then cycles again properly.
Seems much better. I won't say "that's it" yet. But "pretty close" to how things were running before I had problems a couple of weeks' back.
I should mention that my system isn't "steam". It's a gas furnace/boiler, hot water, cast iron radiators. 2-story house built in 1911, no insulation, plaster walls, original windows.
That's why I used the "gas hot water" setting first (it's what the plumbing/heating guy set it at, I guess he was going by the manual, too). But that setting clearly was wrong. At least for my system. The "steam" setting works much better.
I may investigate a programmable thermostat that allows the user to manually set the "temperature differential" (I think that's what it's called). The manual for this Lux unit: (Amazon.com product link shortened)89&creative25&creativeASIN044UYVFW&linkCode=as2&tag=hvac0a0-20&linkId2fece5666350ad62adbb6929419807b ... says the swing setting can be programmed to 2.25 degrees F.
Question: If set to the 2.25 setting, does that mean 2.25 degrees -below- the set temp and 2.25 -above it-, as well? That would be pretty close to "what I'm looking for".
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J.Albert wrote: "should mention that my system isn't "steam". It's a gas furnace/boiler, hot water, cast iron radiators. 2-story house built in 1911, no insulation, plaster walls, original windows. "
My Gods Jim! Tighten up that draft stack you reside in: Insulate at least the attic, repair any cracks in the plaster walls and ceiling, and weatherstrip all exterior doors.
Then you can have your +- 2.25 degree temp swing using less of our precious resources.
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On 4/10/2018 12:06 AM, J.Albert wrote:

Does the boiler run for domestic hot water also? That would account for running with no circulation.

After 100 years you'd think someone would be smart enough to insulate. You boiler will run much less once you do and it will pay for itself quickly, plus add comfort. Less run time, little temperature swing.
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1. I think you have a boiler problem that you are trying to fix with a the rmostat. Not gonna work. Might as well just put an On-Off switch on the b oiler and run it manually until it breaks all the way.
2. When I grew up in Wisconsin, the thermostat controlled the boiler and t he circulating pump ran any time the boiler ran. That might not be the way yours worked. Radiators are slow to heat up and the room even slower, so there's no way our boiler cycled very often. In cold weather it never shut off and didn't quite keep up, but that's what sweaters and blankets are fo r.
3. When I lived in Germany the boiler maintained a loop temperature, zone valves opened for area demand, and each radiator had a thermostat on it. T he boiler loop temperature had a set back. If it was 0 F outside, it would run 160 F; if it was 60 F, it would run 120. Or something like that, I fo rget exactly. Of course the walls were a foot thick, masonry covered with plaster which totally eliminates infiltration, and triple pane windows.
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On 4/10/18 9:18 AM, Ed Pawlowski wrote:

Can't install insulation (at least the "blown in" kind). I also have original knob-and-tube wiring, and I believe that the recommendation is that blown-in insulation SHOULD NOT be used with K&T.
There is insulation in the attic -- directly under the shingles!
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J.Albert wrote: "endation is that blown-in insulation SHOULD NOT be used with K&T. "
Understood. Not totally upon those details.
"There is insulation in the attic -- directly under the shingles! "
ERRRR!!
Unless there is finished living space in that attic, the insulation belongs in the attic FLOOR, not up between the rafters. The attic roof is open at the gutter sides, and serves as shelter against wind and precipitation.
In a home with unoccupied attic space, you insulate between the upstairs ceiling studs, not betw. rafters. Sheesh! Americans... No WONDER they consume billions of gallons of heating oil per season. Cain't even insoolayt properlee!
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I had K&T which I removed, but I never insulated before I sold. Could have, should have.
I had a couple cycle rate thermostats, got rid of them. Now it's strictly following temperature on forced air.
Greg
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On 4/7/2018 9:27 AM, J.Albert wrote:

You have the right to want what you want. BUT If you disclosed the details behind what you want, some of us might decide that we wanted to do that too. At this point, it seems that nobody can see any benefit so they won't waste effort considering a solution. The thread is devolving into name calling, as internet discussions always do.
More people thinking about it positively can result in a quicker solution.
IRRC, somebody mentioned that you have a boiler, not a furnace. I missed the response to that. Seems like the answer might be relevant.
My thermostat has the ability to set different temperatures at different times. I'm home almost all the time, so I set it at 66F and don't worry about it. If I'm cold, I put on a thicker shirt.

Thermal mass should be able to do that.
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On Saturday, April 7, 2018 at 12:57:07 AM UTC-4, mike wrote:

That is almost certainly what they are doing. I have a HW VisionPro and that is exactly what it does, you set the number of cycles per hour that you want the system to run. It will target that for when it's maintaining the set temp. They also have guidelines like he posted for different suggested cycles based on type of sytem, eg gas, electric, etc.

I don't see how that solves anything. A resistor is like the heat anticipator that old thermostats had. All it can do is cause the thermostat to warm up quicker than the room and turn off the system a bit early. The idea there is that there is residual heat that will then bring the room up to the final set temp. He wants a 6 point swing, which would mean you'd have to trick the furnace out in the opposite direction, ie make it go way past where it would otherwise turn off. He's need a cooler, not a resistor.

That would potentially create wider swings. But practically, IDK how much thermal coupling he'd get as opposed to it reacting to the air entering the thermostat.

+1

Those are considerations too.
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On 4/7/2018 9:48 AM, trader_4 wrote:

The intent was to emulate the anticipator. I'd have to agree with your statements. I was thinking that the thermal mass of the resistor would heat rapidly when the furnace was on, but cool slowly by convection in air when the furnace was off. You'd have to do a lot of experimenting...

I couldn't tell from the specs, but it sounds like the sense element is a thermistor that could easily be coupled to thermal mass.

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On Saturday, April 7, 2018 at 2:16:35 PM UTC-4, mike wrote:

I agree, you're right, there is potentially that effect, but the heat would have to last long enough to keep the thermostat above room temp so that it delays it coming on as the room drops. With thermostats there isn't enough mass there for the effect to last more than what? Ten, fifteen minutes? He wouldn't get his several hours, that's for sure.

I would agree that it's a thermistor, but how you couple that to a mass of any real consequuence in the typical modern thermostat, IDK. And it would have to be a heck of big mass to get hours of delay. I guess he could modify it, remove the thermistor, put it on wires, put it between a large mass like two bricks.....
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On 4/6/2018 9:10 PM, J.Albert wrote:

Get a process controller.  Most can be programmed for upper and lower temp limits.
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I am curious Dev, why do you nymshift so much? It seems like you use 20-25 different pseudonym each month. Is it a mental disorder?
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On 04/08/2018 12:13 PM, None wrote:

Why did the chicken cross the road?
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On 4/8/18 11:51 AM, Dev Null wrote:

Thanks for that information. This sounds almost like what I'm looking for.
I just want the furnace (boiler?) to come on when the temperature drops to a point I specify, and shut off when the temperature increases to a point that I specify.
I want it to "cycle", but not too often. Apparently a "normal" home thermostat can't be set up to behave this way. At least not with a "spread" as wide as what I would prefer.
Oddly enough, I don't recall this happening with my old thermostat (that had an old-style predictor/anticipator lever). But the new thermostat which has DIP switches instead of the anticipator doesn't seem to control the furnace as well the old one did.
It seems to turn it on, then shut it off prematurely. Also, it seems I have to set it considerably higher (desired temperature, top indicator) then the lower indicator (actual room temp?) indicates.
Maybe I just have a bad thermostat.
All this began because the furnace wasn't working properly. It wouldn't go through the ignition process reliably. The plumbing/heating guy cleaned the flame sensor and put on a fresh spark/sensor cable. He also replaced the thermostat with the one I have now.
It looked ok when he left, but then the ignition/startup problems began to recur. Furnace would try to start and you'd hear a "chattering" inside the intermittent control module (old Honeywell s86h). Sounded like there was a relay inside that wasn't holding. I could rap mildly on the side of the controller, and it would "catch", after which the furnace ran ok -- until the next startup, might do the same thing.
The module was 30 years old, and it was possible that it was failing. So, I replaced it myself with a new "universal" Honeywell module (checked documentation carefully so I knew it was the right replacement).
The furnace now starts reliably: 1. ignition spark on 2. pilot valve opens, pilot lights 3. flame rectification occurs, spark ends 4. main valve opens, burners light The LED light on the module shows normal operation.
But... again because of the thermostat, it seems to get shut down prematurely (if I set the thermostat to call for a "regular temperature", say 68 degrees).
IF I set the desired temp on the thermostat "way over" where it would be regularly set -- say to 85 degrees -- the furnace runs fine, UNTIL I set the thermostat back down to "way low" (say, 55 degrees). No overheating or thermal cut-off. It seems to run fine.
I can do this manually, but (of course!) would prefer it to run automatically without my intervention. But the new thermostat is giving me trouble.
I've set the internal DIP switches to 1 "CPH" (cycle per hour?), which isn't the recommended setting (it's the "recommended setting" that's giving me the problems!) but haven't had a chance to really observe the results yet.
Thanks for reading.
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