What I have:
Burnham gas furnace, hot water, model P205 WI (it's 30 years
old but still in good condition)
There's no stack vent (it had an old HyTemp which I've
disconnected electrically and locked open).
No fans of any kind.
Electric circulating pump.
House is old (but not large) and has big cast-iron radiators.

I was having some problems (furnace wouldn't start
correctly), had my plumber/heating guy come over. Checked
the pilot/ignition, cleaned the sensor.
He installed a new thermostat (old one must have been 40+
years old).
The new thermostat is a Honeywell "round" T87K1007.
There are only two wires from the furnace that connect to it.
No fans, no air conditioning.

The furnace still wasn't right afterwards, but I
investigated on my own and came to the conclusion that the
intermittent ignition module (old Honeywell S86H) had
something inside that was failing. I replaced it with a new
Honeywell "universal" module (S8610U3009/U), and that seems
to have solved the problems with the furnace.

But I find that the new thermostat is quirky.
The "room temperature" indication (bottom pointer) seems to
have no relationship to the "desired temp" setting (top
pointer that you set by rotating the dial).

I checked the thermostat's DIP switches (it has these
instead of the "predictor" that the old one has), and found
one that wasn't set according to the manual, and reset it.

But... I've come to the conclusion that the thermostat
doesn't do what I want it to do.
Please keep reading.

I understand that a thermostat is intended to automatically
maintain room temperature within a slight variation from the
desired target setting. Perhaps within 1 degree +/-?

The result is that the furnace cycles on/off too much for
what I want.

What I've been doing (it's still cold at night here in
southern New England yet) is setting the thermostat up
higher than where I want, letting the furnace run for an
hour, then turning the thermostat down (and furnace off)
until it gets a little cooler than I like.

I can repeat this two or three times a day, and that's all I
need.

So....
I know there are "smart thermostats" one can buy, but I
still don't know if they can do what I want. Which is:
- set a high temp limit (furnace shuts off)
- set a low temp limit (furnace turns on)
Say, set my low for 64 degrees and my high for 70 degrees.
Or something like that.

Are there any thermostats out that that work this way?
Or do they ALL "cycle within" a smaller range of temperature
change?

On 4/6/2018 9:10 PM, J.Albert wrote:
What I have:
Burnham gas furnace, hot water,
So....
I know there are "smart thermostats" one can buy, but I still don't know
if they can do what I want. Which is:
- set a high temp limit (furnace shuts off)
- set a low temp limit (furnace turns on)
Say, set my low for 64 degrees and my high for 70 degrees. Or something
like that.

Yes, but you don't have a furnace, you have a boiler. The boiler will
have limit switches on it that will shut it off at a maximum water
temperature for safety. The thermostat controls the circulator pump.

On 4/6/18 8:10 PM, J.Albert wrote:
What I have:
Burnham gas furnace, hot water, model P205 WI (it's 30 years old but
still in good condition)
There's no stack vent (it had an old HyTemp which I've disconnected
electrically and locked open).
No fans of any kind.
Electric circulating pump.
House is old (but not large) and has big cast-iron radiators.

I was having some problems (furnace wouldn't start correctly), had my
plumber/heating guy come over. Checked the pilot/ignition, cleaned the
sensor.
He installed a new thermostat (old one must have been 40+ years old).
The new thermostat is a Honeywell "round" T87K1007.
There are only two wires from the furnace that connect to it.
No fans, no air conditioning.

The furnace still wasn't right afterwards, but I investigated on my own
and came to the conclusion that the intermittent ignition module (old
Honeywell S86H) had something inside that was failing. I replaced it
with a new Honeywell "universal" module (S8610U3009/U), and that seems
to have solved the problems with the furnace.

But I find that the new thermostat is quirky.
The "room temperature" indication (bottom pointer) seems to have no
relationship to the "desired temp" setting (top pointer that you set by
rotating the dial).

I checked the thermostat's DIP switches (it has these instead of the
"predictor" that the old one has), and found one that wasn't set
according to the manual, and reset it.

But... I've come to the conclusion that the thermostat doesn't do what I
want it to do.
Please keep reading.

I understand that a thermostat is intended to automatically maintain
room temperature within a slight variation from the desired target
setting. Perhaps within 1 degree +/-?

The result is that the furnace cycles on/off too much for what I want.

What I've been doing (it's still cold at night here in southern New
England yet) is setting the thermostat up higher than where I want,
letting the furnace run for an hour, then turning the thermostat down
(and furnace off) until it gets a little cooler than I like.

I can repeat this two or three times a day, and that's all I need.

So....
I know there are "smart thermostats" one can buy, but I still don't know
if they can do what I want. Which is:
- set a high temp limit (furnace shuts off)
- set a low temp limit (furnace turns on)
Say, set my low for 64 degrees and my high for 70 degrees. Or something
like that.

Are there any thermostats out that that work this way?
Or do they ALL "cycle within" a smaller range of temperature change?

This is a bit dated but might help:
http://programmablethermostatreviews.biz/swing-control-explained/

On 4/6/2018 9:10 PM, J.Albert wrote:
What I have:
Burnham gas furnace, hot water, model P205 WI (it's 30 years old but
still in good condition)
There's no stack vent (it had an old HyTemp which I've disconnected
electrically and locked open).
No fans of any kind.
Electric circulating pump.
House is old (but not large) and has big cast-iron radiators.

I was having some problems (furnace wouldn't start correctly), had my
plumber/heating guy come over. Checked the pilot/ignition, cleaned the
sensor.
He installed a new thermostat (old one must have been 40+ years old).
The new thermostat is a Honeywell "round" T87K1007.
There are only two wires from the furnace that connect to it.
No fans, no air conditioning.

The furnace still wasn't right afterwards, but I investigated on my own
and came to the conclusion that the intermittent ignition module (old
Honeywell S86H) had something inside that was failing. I replaced it
with a new Honeywell "universal" module (S8610U3009/U), and that seems
to have solved the problems with the furnace.

But I find that the new thermostat is quirky.
The "room temperature" indication (bottom pointer) seems to have no
relationship to the "desired temp" setting (top pointer that you set by
rotating the dial).

I checked the thermostat's DIP switches (it has these instead of the
"predictor" that the old one has), and found one that wasn't set
according to the manual, and reset it.

But... I've come to the conclusion that the thermostat doesn't do what I
want it to do.
Please keep reading.

I understand that a thermostat is intended to automatically maintain
room temperature within a slight variation from the desired target
setting. Perhaps within 1 degree +/-?

The result is that the furnace cycles on/off too much for what I want.

What I've been doing (it's still cold at night here in southern New
England yet) is setting the thermostat up higher than where I want,
letting the furnace run for an hour, then turning the thermostat down
(and furnace off) until it gets a little cooler than I like.

I can repeat this two or three times a day, and that's all I need.

So....
I know there are "smart thermostats" one can buy, but I still don't know
if they can do what I want. Which is:
- set a high temp limit (furnace shuts off)
- set a low temp limit (furnace turns on)
Say, set my low for 64 degrees and my high for 70 degrees. Or something
like that.

Are there any thermostats out that that work this way?
Or do they ALL "cycle within" a smaller range of temperature change?

Are the cycle rate switches both set to "On"? That will allow 1 cycle
per hour.


MikeB

On 4/6/18 10:52 PM, BQ340 wrote:
Are the cycle rate switches both set to "On"? That will
allow 1 cycle per hour.

This thermostat has DIP switches.

There are 2 of them. Here are the possible choices:
on/on - steam or gravity (1 CPH)
off/on - high efficiency warm air, hot water, or heat pump
(3 CPH)
off/off - gas or oil warm air (5 CPH)
on/off - electric warm air (9 CPH)

Because mine is gas/hot water, I have the second choice
above selected.

Should I try the on/on position, then?

Actually, even with that, it's still not what I would prefer.
I want the furnace to come on when room temperature drops
to, say, 64 degrees.
I want the furnace to STAY ON until the temperature reaches
70 degrees, then shut off until the temp again drops down to 64.

Are there any thermostats that can do that?

In "J.Albert" writes:


Actually, even with that, it's still not what I would prefer.
I want the furnace to come on when room temperature drops
to, say, 64 degrees.
I want the furnace to STAY ON until the temperature reaches
70 degrees, then shut off until the temp again drops down to 64.

Are there any thermostats that can do that?

This is usually set to minimize temperature swings,
but if you turn it the other way, who knows?

https://www.thespruce.com/thermostat...stment-1824756


--
__________________________________________________ ___
Knowledge may be power, but communications is the key

[to foil spammers, my address has been double rot-13 encoded]

On 4/6/18 10:27 PM, J.Albert wrote:
On 4/6/18 10:52 PM, BQ340 wrote:
Are the cycle rate switches both set to "On"? That will allow 1 cycle
per hour.

This thermostat has DIP switches.

There are 2 of them. Here are the possible choices:
on/on - steam or gravity (1 CPH)
off/on - high efficiency warm air, hot water, or heat pump (3 CPH)
off/off - gas or oil warm air (5 CPH)
on/off - electric warm air (9 CPH)

Because mine is gas/hot water, I have the second choice above selected.

Should I try the on/on position, then?

Actually, even with that, it's still not what I would prefer.
I want the furnace to come on when room temperature drops to, say, 64
degrees.
I want the furnace to STAY ON until the temperature reaches 70 degrees,
then shut off until the temp again drops down to 64.

Are there any thermostats that can do that?

Well, according to the article I cited Honeywell works a bit
differently
than all Lux thermostats and the Hunter 44550 Auto Save.

"All Lux Products thermostats come with swing control as does the Hunter
44550 Auto Save. What is a mystery to those looking at thermostats is
why there is no swing control on Honeywell thermostats. It is not a
simple oversight on Honeywells part. Honeywell is one of the earliest
makers of control technology for the home and they have deliberately
done away with the idea of swing control."

On Saturday, April 7, 2018 at 6:35:15 AM UTC-4, Dean Hoffman wrote:
On 4/6/18 10:27 PM, J.Albert wrote:
On 4/6/18 10:52 PM, BQ340 wrote:
Are the cycle rate switches both set to "On"? That will allow 1 cycle
per hour.

This thermostat has DIP switches.

There are 2 of them. Here are the possible choices:
on/on - steam or gravity (1 CPH)
off/on - high efficiency warm air, hot water, or heat pump (3 CPH)
off/off - gas or oil warm air (5 CPH)
on/off - electric warm air (9 CPH)

Because mine is gas/hot water, I have the second choice above selected.

Should I try the on/on position, then?

Actually, even with that, it's still not what I would prefer.
I want the furnace to come on when room temperature drops to, say, 64
degrees.
I want the furnace to STAY ON until the temperature reaches 70 degrees,
then shut off until the temp again drops down to 64.

Are there any thermostats that can do that?

Well, according to the article I cited Honeywell works a bit
differently
than all Lux thermostats and the Hunter 44550 Auto Save.

"All Lux Products thermostats come with swing control as does the Hunter
44550 Auto Save. What is a mystery to those looking at thermostats is
why there is no swing control on Honeywell thermostats. It is not a
simple oversight on Honeywells part. Honeywell is one of the earliest
makers of control technology for the home and they have deliberately
done away with the idea of swing control."

That's right, at least with the Honeywell thermostats that I've used recently. They set the number of cycles per hour desired, not a temp swing range. I'd be surprised if even an old mercury thermostat with a heat anticipator could do a 6 deg swing. Nor do I see why anyone would want it. I'd call that a busted thermostat.

trader_4:

Sounds like H-Well went cheapo post-mercury
bulb jobs. Offering just a few presets in the form
either of dip-switches or 3 menu choices of #
of firings per hour.

With the old heat-insemenator-antessimator
GOL-DANGIT - Anticipators(!), like on the
mechanical HW setback formerly in my parents
place, if one knew what they were doing,
they'd measure the voltage to set the
anticipator by, and could get the temperature
swing to less than one degree F° above or
below desired set point.(as long as the thing
was mounted perfectly level on a wall near
no drafts)

On 4/6/2018 6:10 PM, J.Albert wrote:
What I have:
Burnham gas furnace, hot water, model P205 WI (it's 30 years old but
still in good condition)
There's no stack vent (it had an old HyTemp which I've disconnected
electrically and locked open).
No fans of any kind.
Electric circulating pump.
House is old (but not large) and has big cast-iron radiators.

I was having some problems (furnace wouldn't start correctly), had my
plumber/heating guy come over. Checked the pilot/ignition, cleaned the
sensor.
He installed a new thermostat (old one must have been 40+ years old).
The new thermostat is a Honeywell "round" T87K1007.
There are only two wires from the furnace that connect to it.
No fans, no air conditioning.

The furnace still wasn't right afterwards, but I investigated on my own
and came to the conclusion that the intermittent ignition module (old
Honeywell S86H) had something inside that was failing. I replaced it
with a new Honeywell "universal" module (S8610U3009/U), and that seems
to have solved the problems with the furnace.

But I find that the new thermostat is quirky.
The "room temperature" indication (bottom pointer) seems to have no
relationship to the "desired temp" setting (top pointer that you set by
rotating the dial).

I checked the thermostat's DIP switches (it has these instead of the
"predictor" that the old one has), and found one that wasn't set
according to the manual, and reset it.

But... I've come to the conclusion that the thermostat doesn't do what I
want it to do.
Please keep reading.

I understand that a thermostat is intended to automatically maintain
room temperature within a slight variation from the desired target
setting. Perhaps within 1 degree +/-?

The result is that the furnace cycles on/off too much for what I want.

Emotion aside...
What is it that makes a stable temperature undesirable?
Can you put back the old thermostat?
The thermostat datasheet suggests that the jumpers might be setting
the number of cycles...but that's vague.
You can emulate the predictor by putting a resistor in series with
the thermostat and placing the resistor proximate to the temperature
sensing element. You'd have to do a lot of experimenting to determine
the resistance and proximity.

Try bolting the thermostat to something with large thermal mass
and restricting the coupling between the air and the sensing element.

What I've been doing (it's still cold at night here in southern New
England yet) is setting the thermostat up higher than where I want,
letting the furnace run for an hour, then turning the thermostat down
(and furnace off) until it gets a little cooler than I like.

I can repeat this two or three times a day, and that's all I need.

So....
I know there are "smart thermostats" one can buy, but I still don't know
if they can do what I want. Which is:
- set a high temp limit (furnace shuts off)
- set a low temp limit (furnace turns on)
Say, set my low for 64 degrees and my high for 70 degrees. Or something
like that.

Are there any thermostats out that that work this way?
Or do they ALL "cycle within" a smaller range of temperature change?
They're doing what they were designed to do.

High/Low setpoint thermostats used to be all over ebay for less than $10,
but all the ones I checked were "no longer available".

I'm still struggling with why it's worth a lot of trouble to make
your temperature unstable.

When modifying HVAC, it's important to ask yourself two questions...

1)What might go horribly wrong?
You can easily convince yourself that any catastrophic failure is
highly unlikely. Problem with statistics is that they are useless
in the individual case. A pregnant teenager is not comforted
by arguments that birth control is 99% effective.

2)Will my fire insurance cover my stupidity?

I think J.Albert is trying to use this particular
model in a setback manner. What he needs
is a programmable thermostat or even an
older mechanical setback with just one
adjustable setback period.

I know if the temperature in my house swung
up and down like something at Six Flags I
would not be too comfy, especially in Winter.

Also, are Albert's radiators properly bled,
does he have a circulator installed in his
system, and.... Are the radiators free and
clear - that is, nothing directly on top of,
to the sides of, or in front, blocking their
radiating properties? And is thermo on
an interior wall, away from windows,
exterior doors, and from any radiator?

On 4/7/18 12:56 AM, mike wrote:
What is it that makes a stable temperature undesirable?

I want the furnace to run only once every few hours.
I'm willing to put up with the temperature swings as a
result of doing so. I realize that may be different from
what most others might want or expect.
But that's what _I_ want.

That's what I'm doing now.
I turn the thermostat "way up" before bed, let things get
just a little "overly warm".
Then I turn the thermostate "way down" so that the furnace
won't run at all overnight.
Of course, it's on the chilly side in the morning, so I
repeat the process.
A good "warm up" in the morning seems to last all the way
into the evening at this time of year.

I'd like to set those "wide swing points" on the thermostat
itself.
But if I can't, I'll just set them manually (I'm retired and
home most of the time).

On 4/7/18 11:27 AM, J.Albert wrote:
On 4/7/18 12:56 AM, mike wrote:
What is it that makes a stable temperature undesirable?

I want the furnace to run only once every few hours.
I'm willing to put up with the temperature swings as a result of doing
so. I realize that may be different from what most others might want or
expect.
But that's what _I_ want.

That's what I'm doing now.
I turn the thermostat "way up" before bed, let things get just a little
"overly warm".
Then I turn the thermostate "way down" so that the furnace won't run at
all overnight.
Of course, it's on the chilly side in the morning, so I repeat the process.
A good "warm up" in the morning seems to last all the way into the
evening at this time of year.

I'd like to set those "wide swing points" on the thermostat itself.
But if I can't, I'll just set them manually (I'm retired and home most
of the time).

Would it work to put some sort of a timer between the thermostat
and the
furnace? The furnace wouldn't kick on no matter what the thermostat does
for a set time.

On Saturday, April 7, 2018 at 12:27:21 PM UTC-4, J.Albert wrote:
On 4/7/18 12:56 AM, mike wrote:
What is it that makes a stable temperature undesirable?

I want the furnace to run only once every few hours.
I'm willing to put up with the temperature swings as a
result of doing so. I realize that may be different from
what most others might want or expect.
But that's what _I_ want.

That still doesn't explain *why* you want it.



That's what I'm doing now.
I turn the thermostat "way up" before bed, let things get
just a little "overly warm".
Then I turn the thermostate "way down" so that the furnace
won't run at all overnight.

Most people do that with a programmable thermostat that automatically
sets it back at a time you set at night and resumes it again at a
time you set for the morning.



Of course, it's on the chilly side in the morning, so I
repeat the process.

If you choose the resume time an hour or so before you get up,
then it's warm. Also, many new Honeywell and many similar thermostats
have adaptive recovery where you just set it for a desired temp
of 70F at 7AM and the thermostat figures out from experience what
time to fire up the heat so that it will be 70F at 7AM.





A good "warm up" in the morning seems to last all the way
into the evening at this time of year.

I'd like to set those "wide swing points" on the thermostat
itself.
But if I can't, I'll just set them manually (I'm retired and
home most of the time).

You might find some thermostat that allows a 6F range between swing
points, but I tend to doubt it, for obvious reasons. And you won't
find it with one that uses cycles, like the HW one that you have,
because they don't have a range that can be set at all. What kind
of thermostat did you have before that allowed this kind of operation?
Where did it go? I've never seen one that could work the way you
describe.

On 4/7/2018 12:41 PM, trader_4 wrote:
On Saturday, April 7, 2018 at 12:27:21 PM UTC-4, J.Albert wrote:
On 4/7/18 12:56 AM, mike wrote:
What is it that makes a stable temperature undesirable?

I want the furnace to run only once every few hours.
I'm willing to put up with the temperature swings as a
result of doing so. I realize that may be different from
what most others might want or expect.
But that's what _I_ want.

That still doesn't explain *why* you want it.



I mentioned that he has a boiler and it has a high limit switch that
turns off the burner, but there was no response. It really makes no
sense to intentionally have wide temperature swings as you have
discomfort with no benefits.

My guess it is a completely misguided attempt at something.

On 4/7/18 12:45 PM, Ed Pawlowski wrote:

I mentioned that he has a boiler and it has a high limit
switch that turns off the burner, but there was no response.

OP here.
If there's a "high limit" switch, it hasn't activated.
(that would be on the aquastat, right?)

I don't really want the furnace cycling on/off repeatedly,
just to maintain a specific setting on the thermostat by
(say) +/- 1 degree, or even 2 degrees.

I don't mind a drop of 3-4 degrees (or even a bit more)
between having it run.

What's really so hard to understand about that?

Having said that, I guess there really isn't a product on
the market that can do this. If I was creative, I'd -build-
one. Just to prove it could be done.

I may try using the DIP setting that's supposed to limit
cycling to once per hour, and let it go at that.

Thanks for your contributions, anyway...

On 4/7/2018 9:27 AM, J.Albert wrote:
On 4/7/18 12:56 AM, mike wrote:
What is it that makes a stable temperature undesirable?

I want the furnace to run only once every few hours.
I'm willing to put up with the temperature swings as a result of doing
so. I realize that may be different from what most others might want or
expect.
But that's what _I_ want.

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.

That's what I'm doing now.
I turn the thermostat "way up" before bed, let things get just a little
"overly warm".
Then I turn the thermostate "way down" so that the furnace won't run at
all overnight.
Of course, it's on the chilly side in the morning, so I repeat the process.
A good "warm up" in the morning seems to last all the way into the
evening at this time of year.

I'd like to set those "wide swing points" on the thermostat itself.
But if I can't, I'll just set them manually (I'm retired and home most
of the time).
Thermal mass should be able to do that.

On Saturday, April 7, 2018 at 12:57:07 AM UTC-4, mike wrote:
On 4/6/2018 6:10 PM, J.Albert wrote:
What I have:
Burnham gas furnace, hot water, model P205 WI (it's 30 years old but
still in good condition)
There's no stack vent (it had an old HyTemp which I've disconnected
electrically and locked open).
No fans of any kind.
Electric circulating pump.
House is old (but not large) and has big cast-iron radiators.

I was having some problems (furnace wouldn't start correctly), had my
plumber/heating guy come over. Checked the pilot/ignition, cleaned the
sensor.
He installed a new thermostat (old one must have been 40+ years old).
The new thermostat is a Honeywell "round" T87K1007.
There are only two wires from the furnace that connect to it.
No fans, no air conditioning.

The furnace still wasn't right afterwards, but I investigated on my own
and came to the conclusion that the intermittent ignition module (old
Honeywell S86H) had something inside that was failing. I replaced it
with a new Honeywell "universal" module (S8610U3009/U), and that seems
to have solved the problems with the furnace.

But I find that the new thermostat is quirky.
The "room temperature" indication (bottom pointer) seems to have no
relationship to the "desired temp" setting (top pointer that you set by
rotating the dial).

I checked the thermostat's DIP switches (it has these instead of the
"predictor" that the old one has), and found one that wasn't set
according to the manual, and reset it.

But... I've come to the conclusion that the thermostat doesn't do what I
want it to do.
Please keep reading.

I understand that a thermostat is intended to automatically maintain
room temperature within a slight variation from the desired target
setting. Perhaps within 1 degree +/-?

The result is that the furnace cycles on/off too much for what I want.

Emotion aside...
What is it that makes a stable temperature undesirable?
Can you put back the old thermostat?
The thermostat datasheet suggests that the jumpers might be setting
the number of cycles...but that's vague.

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.



You can emulate the predictor by putting a resistor in series with
the thermostat and placing the resistor proximate to the temperature
sensing element. You'd have to do a lot of experimenting to determine
the resistance and proximity.

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.




Try bolting the thermostat to something with large thermal mass
and restricting the coupling between the air and the sensing element.

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.



What I've been doing (it's still cold at night here in southern New
England yet) is setting the thermostat up higher than where I want,
letting the furnace run for an hour, then turning the thermostat down
(and furnace off) until it gets a little cooler than I like.

I can repeat this two or three times a day, and that's all I need.

So....
I know there are "smart thermostats" one can buy, but I still don't know
if they can do what I want. Which is:
- set a high temp limit (furnace shuts off)
- set a low temp limit (furnace turns on)
Say, set my low for 64 degrees and my high for 70 degrees. Or something
like that.

Are there any thermostats out that that work this way?
Or do they ALL "cycle within" a smaller range of temperature change?
They're doing what they were designed to do.

High/Low setpoint thermostats used to be all over ebay for less than $10,
but all the ones I checked were "no longer available".

I'm still struggling with why it's worth a lot of trouble to make
your temperature unstable.

+1




When modifying HVAC, it's important to ask yourself two questions...

1)What might go horribly wrong?
You can easily convince yourself that any catastrophic failure is
highly unlikely. Problem with statistics is that they are useless
in the individual case. A pregnant teenager is not comforted
by arguments that birth control is 99% effective.

2)Will my fire insurance cover my stupidity?

Those are considerations too.

On 4/7/2018 9:48 AM, trader_4 wrote:
On Saturday, April 7, 2018 at 12:57:07 AM UTC-4, mike wrote:
On 4/6/2018 6:10 PM, J.Albert wrote:
What I have:
Burnham gas furnace, hot water, model P205 WI (it's 30 years old but
still in good condition)
There's no stack vent (it had an old HyTemp which I've disconnected
electrically and locked open).
No fans of any kind.
Electric circulating pump.
House is old (but not large) and has big cast-iron radiators.

I was having some problems (furnace wouldn't start correctly), had my
plumber/heating guy come over. Checked the pilot/ignition, cleaned the
sensor.
He installed a new thermostat (old one must have been 40+ years old).
The new thermostat is a Honeywell "round" T87K1007.
There are only two wires from the furnace that connect to it.
No fans, no air conditioning.

The furnace still wasn't right afterwards, but I investigated on my own
and came to the conclusion that the intermittent ignition module (old
Honeywell S86H) had something inside that was failing. I replaced it
with a new Honeywell "universal" module (S8610U3009/U), and that seems
to have solved the problems with the furnace.

But I find that the new thermostat is quirky.
The "room temperature" indication (bottom pointer) seems to have no
relationship to the "desired temp" setting (top pointer that you set by
rotating the dial).

I checked the thermostat's DIP switches (it has these instead of the
"predictor" that the old one has), and found one that wasn't set
according to the manual, and reset it.

But... I've come to the conclusion that the thermostat doesn't do what I
want it to do.
Please keep reading.

I understand that a thermostat is intended to automatically maintain
room temperature within a slight variation from the desired target
setting. Perhaps within 1 degree +/-?

The result is that the furnace cycles on/off too much for what I want.

Emotion aside...
What is it that makes a stable temperature undesirable?
Can you put back the old thermostat?
The thermostat datasheet suggests that the jumpers might be setting
the number of cycles...but that's vague.

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.



You can emulate the predictor by putting a resistor in series with
the thermostat and placing the resistor proximate to the temperature
sensing element. You'd have to do a lot of experimenting to determine
the resistance and proximity.

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.

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...



Try bolting the thermostat to something with large thermal mass
and restricting the coupling between the air and the sensing element.

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.

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.



What I've been doing (it's still cold at night here in southern New
England yet) is setting the thermostat up higher than where I want,
letting the furnace run for an hour, then turning the thermostat down
(and furnace off) until it gets a little cooler than I like.

I can repeat this two or three times a day, and that's all I need.

So....
I know there are "smart thermostats" one can buy, but I still don't know
if they can do what I want. Which is:
- set a high temp limit (furnace shuts off)
- set a low temp limit (furnace turns on)
Say, set my low for 64 degrees and my high for 70 degrees. Or something
like that.

Are there any thermostats out that that work this way?
Or do they ALL "cycle within" a smaller range of temperature change?
They're doing what they were designed to do.

High/Low setpoint thermostats used to be all over ebay for less than $10,
but all the ones I checked were "no longer available".

I'm still struggling with why it's worth a lot of trouble to make
your temperature unstable.

+1




When modifying HVAC, it's important to ask yourself two questions...

1)What might go horribly wrong?
You can easily convince yourself that any catastrophic failure is
highly unlikely. Problem with statistics is that they are useless
in the individual case. A pregnant teenager is not comforted
by arguments that birth control is 99% effective.

2)Will my fire insurance cover my stupidity?

Those are considerations too.

On Saturday, April 7, 2018 at 2:16:35 PM UTC-4, mike wrote:
On 4/7/2018 9:48 AM, trader_4 wrote:
On Saturday, April 7, 2018 at 12:57:07 AM UTC-4, mike wrote:
On 4/6/2018 6:10 PM, J.Albert wrote:
What I have:
Burnham gas furnace, hot water, model P205 WI (it's 30 years old but
still in good condition)
There's no stack vent (it had an old HyTemp which I've disconnected
electrically and locked open).
No fans of any kind.
Electric circulating pump.
House is old (but not large) and has big cast-iron radiators.

I was having some problems (furnace wouldn't start correctly), had my
plumber/heating guy come over. Checked the pilot/ignition, cleaned the
sensor.
He installed a new thermostat (old one must have been 40+ years old).
The new thermostat is a Honeywell "round" T87K1007.
There are only two wires from the furnace that connect to it.
No fans, no air conditioning.

The furnace still wasn't right afterwards, but I investigated on my own
and came to the conclusion that the intermittent ignition module (old
Honeywell S86H) had something inside that was failing. I replaced it
with a new Honeywell "universal" module (S8610U3009/U), and that seems
to have solved the problems with the furnace.

But I find that the new thermostat is quirky.
The "room temperature" indication (bottom pointer) seems to have no
relationship to the "desired temp" setting (top pointer that you set by
rotating the dial).

I checked the thermostat's DIP switches (it has these instead of the
"predictor" that the old one has), and found one that wasn't set
according to the manual, and reset it.

But... I've come to the conclusion that the thermostat doesn't do what I
want it to do.
Please keep reading.

I understand that a thermostat is intended to automatically maintain
room temperature within a slight variation from the desired target
setting. Perhaps within 1 degree +/-?

The result is that the furnace cycles on/off too much for what I want.

Emotion aside...
What is it that makes a stable temperature undesirable?
Can you put back the old thermostat?
The thermostat datasheet suggests that the jumpers might be setting
the number of cycles...but that's vague.

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.



You can emulate the predictor by putting a resistor in series with
the thermostat and placing the resistor proximate to the temperature
sensing element. You'd have to do a lot of experimenting to determine
the resistance and proximity.

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.

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 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.








Try bolting the thermostat to something with large thermal mass
and restricting the coupling between the air and the sensing element.

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.

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.

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.....

On 4/6/2018 9:10 PM, J.Albert wrote:
What I have:
Burnham gas furnace, hot water, model P205 WI (it's 30 years old but still in good condition)
There's no stack vent (it had an old HyTemp which I've disconnected electrically and locked open).
No fans of any kind.
Electric circulating pump.
House is old (but not large) and has big cast-iron radiators.

Get a process controller.Â* Most can be programmed for upper and lower temp limits.

On Sun, 8 Apr 2018 11:51:05 -0400, Dev Null wrote:

On 4/6/2018 9:10 PM, J.Albert wrote:
What I have:
Burnham gas furnace, hot water, model P205 WI (it's 30 years old but still in good condition)
There's no stack vent (it had an old HyTemp which I've disconnected electrically and locked open).
No fans of any kind.
Electric circulating pump.
House is old (but not large) and has big cast-iron radiators.

Get a process controller.* Most can be programmed for upper and lower temp limits.

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?

On 04/08/2018 12:13 PM, None wrote:
On Sun, 8 Apr 2018 11:51:05 -0400, Dev Null wrote:

On 4/6/2018 9:10 PM, J.Albert wrote:
What I have:
Burnham gas furnace, hot water, model P205 WI (it's 30 years old but still in good condition)
There's no stack vent (it had an old HyTemp which I've disconnected electrically and locked open).
No fans of any kind.
Electric circulating pump.
House is old (but not large) and has big cast-iron radiators.
Get a process controller.Â* Most can be programmed for upper and lower temp limits.
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?

Why did the chicken cross the road?

On 4/8/18 11:51 AM, Dev Null wrote:
Get a process controller.Â* Most can be programmed for upper
and lower temp limits.

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.