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Triumph
02-12-2012, 09:13 AM
I'm a new(ish) homeowner so I never noticed such things before, but I installed a thermostat, a Honeywell from HD that ran about $60, and the thing turns the furnace on about every 10 minutes and runs it for 7-8 minutes. With my old thermostat, I don't remember it ever operating this frequently. I looked in the manual, there's no option to adjust how sensitive it is (i.e. how much the temperature has to drop before it will turn on). I changed the thermostat in the first place to get the weekday and weekend scheduling options, not sure if that actually saves any money. Seems to me it'd be more efficient to try and keep at a constant temperature rather than losing all that heat during the day and trying to make it up in the evening.

Red Squirrel
02-12-2012, 09:16 AM
The span time is probably too low, so it's short cycling. Is it doing it more when it's really cold? I'm not familiar with that thermostat but see if there's an option called "span", though it may be called something else.

I've been working on a fully custom thermostat, and I'm actually going to set the temp in ranges. It cost less money to run the furnace for a long time, then to run it in a bunch of short cycles so the idea will be to avoid short cycling as much as possible.

Though if you have high heat loss it's harder to avoid.

FoBoT
02-12-2012, 09:17 AM
what kind of 'furnace' is it?

bruceb
02-12-2012, 09:22 AM
We need to know the type of furnace. Oil or Gas fired, hot water baseboard heat or hot air heat. All that makes a difference in how the thermostat options are set up. We also need the exact model of the thermostat that you bought from Home Depot. There are usually a few screw terminals on them and depending on the furnace, you may need to jumper a couple of them or there may be a screw that sets the amount of "on time" before it will go off or come back on again. For example, in a hot air system the fan will stay on a couple of minutes after the furnace goes off.

Triumph
02-12-2012, 09:23 AM
what kind of 'furnace' is it?

Brand I don't remember, but I am in a ~1500 sq ft townhouse in Virginia and it is a gas furnace with electric blower. Today is about 30 degrees outside.

Analog
02-12-2012, 09:28 AM
Sounds like the hysteresis is set to tight. Your older T-stat must have had a wider hysteresis setting. I'm not sure if you are able to change that on the new one.

Red Squirrel
02-12-2012, 09:28 AM
30 degrees F? Yeah the furnace should not be running that often. I could see that when it's like -20 or so. When it stops, is it at the temp you set it at though? If yes, then you could also have major heat loss going on, maybe not enough insulation in the attic.

Triumph
02-12-2012, 09:33 AM
Sounds like the hysteresis is set to tight. Your older T-stat must have had a wider hysteresis setting. I'm not sure if you are able to change that on the new one.

I don't think I can. It is a Honeywell RTH6450. The only thing that comes close in the manual is a "heating cycle rate," which only has the following options:
Set to 5 if you have gas or oil furnace
Set to 9 if you have electric furnace
Set to 3 if you have hot water or high efficiency furnace
Set to 1 if you have gas/oil steam or gravity system

So mine is obviously set to 5. There is nothing else in the manual that I can see that would change this.

Analog
02-12-2012, 09:38 AM
I don't think I can. It is a Honeywell RTH6450. The only thing that comes close in the manual is a "heating cycle rate," which only has the following options:
Set to 5 if you have gas or oil furnace
Set to 9 if you have electric furnace
Set to 3 if you have hot water or high efficiency furnace
Set to 1 if you have gas/oil steam or gravity system

So mine is obviously set to 5. There is nothing else in the manual that I can see that would change this.

I don't know about yours, but some have set-screw adjustments on the back side for such things.

JEDI
02-12-2012, 10:12 AM
I'm a new(ish) homeowner so I never noticed such things before, but I installed a thermostat, a Honeywell from HD that ran about $60, and the thing turns the furnace on about every 10 minutes and runs it for 7-8 minutes. With my old thermostat, I don't remember it ever operating this frequently. I looked in the manual, there's no option to adjust how sensitive it is (i.e. how much the temperature has to drop before it will turn on). I changed the thermostat in the first place to get the weekday and weekend scheduling options, not sure if that actually saves any money. Seems to me it'd be more efficient to try and keep at a constant temperature rather than losing all that heat during the day and trying to make it up in the evening.

my lux programmable thermostat says my system should cycle 3 to 6 times per hour.

so every 10min sounds like its within range.

Triumph
02-12-2012, 10:29 AM
I turned the heat off after the last cycle, and it took about 25 minutes to drop 1 degree. Granted it is getting warmer outside but I figure this is a good enough test of my insulation (which I know I have problems in the entry hall). I would prefer to adjust this thermostat so that it turned on after dropping 1 degree instead of 1/10th of a degree or whatever it's set to. There's nothing in the manual nor a screw adjustment on the module anywhere that speaks to adjusting this sensitivity.

Anyone have a suggestion for a good thermostat?

my lux programmable thermostat says my system should cycle 3 to 6 times per hour.

so every 10min sounds like its within range.

Thanks for that, that's good feedback.

arcenite
02-12-2012, 10:31 AM
I believe the heating cycling rate is exactly what you should be looking at. Change it to 3 and see if there's any improvement.

Thump553
02-12-2012, 10:32 AM
That's a perfectly good thermostat-I have two of them in central CT and both run perfectly.

Check to see if all the bottom switches are set correctly, then I'd follow Jedi's suggestions and if that doesn't work, call the Honeywell hotline-they are very helpful.

Engineer
02-12-2012, 10:34 AM
Sounds like the hysteresis is set to tight. Your older T-stat must have had a wider hysteresis setting. I'm not sure if you are able to change that on the new one.

This. Most of the programmable thermostats that I've seen have a 1,2 or 3 degree hysteresis.

OT: My new system simply keeps the temperature where it's set by varying the blower speed up/down like a servo system. Most consistent (and cheap - 95.5% efficient) furnace I've ever had.

JEDI
02-12-2012, 10:44 AM
I believe the heating cycling rate is exactly what you should be looking at. Change it to 3 and see if there's any improvement.

why 3?

changing from 5 to 3 will increase sensitivity, thus more cycles?

Rubycon
02-12-2012, 11:00 AM
How many btu/hr is the furnace?
Where is the thermostat located? Usually it's in a hallway away from drafts from doors and located near a return. Digital stats are far more sensitive than aneroid bi-metal old school stats like T87F etc.
Does it have an anticipator?

waggy
02-12-2012, 11:02 AM
ohh im going to piggyback on this thread (sorry op). but I think my thermostat is going (only after 7 years!) it keeps letting the temp drop. the other day it got to 61.

i had it set to 74 during the day and 69 at night. I had to set ot override and to 74 only room that is cool is the office/playroom (haven't got new windows in this room yet)

bruceb
02-12-2012, 11:08 AM
Recheck your settings. Also the type of heating system (hot water baseboard or hot air) and wether it is a newer high efficiency furnace will have to use the correct settings.

Set to 5 if you have gas or oil furnace ... this would be for normal, old hot air furnace
Set to 9 if you have electric furnace .. not many homes have this type
Set to 3 if you have hot water or high efficiency furnace .. hot water baseboard heat or new high efficiency furnace
Set to 1 if you have gas/oil steam or gravity system ... only used if you have steam radiators found in many very older homes

Note you can check the nameplate on the furnace. If it is within say 4 years or so old and has a rating of 80% or higher, it is a high efficiency type of unit.

arcenite
02-12-2012, 11:17 AM
why 3?

changing from 5 to 3 will increase sensitivity, thus more cycles?

It has nothing to do with sensitivity to temperature.

The lower the number the less times per hour the system will kick on and off.

5 = 60/5 = Tstat cycles a maximum of once every 12 mins
3 = 60/3 = Tstat cycles a maximum of once every 20 mins

That's my understanding anyway.

iGas
02-12-2012, 11:57 AM
This. Most of the programmable thermostats that I've seen have a 1,2 or 3 degree hysteresis.

OT: My new system simply keeps the temperature where it's set by varying the blower speed up/down like a servo system. Most consistent (and cheap - 95.5% efficient) furnace I've ever had.
Second the hysteresis theory.

Triumph
02-12-2012, 12:04 PM
Recheck your settings. Also the type of heating system (hot water baseboard or hot air) and wether it is a newer high efficiency furnace will have to use the correct settings.

Set to 5 if you have gas or oil furnace ... this would be for normal, old hot air furnace
Set to 9 if you have electric furnace .. not many homes have this type
Set to 3 if you have hot water or high efficiency furnace .. hot water baseboard heat or new high efficiency furnace
Set to 1 if you have gas/oil steam or gravity system ... only used if you have steam radiators found in many very older homes

Note you can check the nameplate on the furnace. If it is within say 4 years or so old and has a rating of 80% or higher, it is a high efficiency type of unit.


It is a 20 year old Rheem unit. I had the AC serviced last summer and the heat checked out in the fall. It works good, the HVAC guy said it was one of his favorite units and to run it until it dies. Which I plan on doing. So the #5 setting is correct for it.

It has nothing to do with sensitivity to temperature.

The lower the number the less times per hour the system will kick on and off.

5 = 60/5 = Tstat cycles a maximum of once every 12 mins
3 = 60/3 = Tstat cycles a maximum of once every 20 mins

That's my understanding anyway.

Even though the #5 setting is technically correct for me, I will try setting it to 3 and see what happens. I don't like this unit, the manual should make some explanation of what this setting is, without you and I having to guess at it.

ElFenix
02-12-2012, 12:12 PM
Seems to me it'd be more efficient to try and keep at a constant temperature rather than losing all that heat during the day and trying to make it up in the evening.

it's not.

yh125d
02-12-2012, 12:45 PM
it's not.

Yeah, in fact that's pretty much the sole reason programmable timer t-stats were invented.

DrPizza
02-12-2012, 01:17 PM
To answer your other question, yes, it saves energy. Your house loses energy at a rate proportional to the difference in temperature between indoors and outside.

LiuKangBakinPie
02-12-2012, 01:24 PM
I can honestly say that everyone I have sex with always smokes after!

Then again I am the furnace operator at the crematorium.

waggy
02-12-2012, 01:30 PM
I can honestly say that everyone I have sex with always smokes after!

Then again I am the furnace operator at the crematorium.

/facepalm

lol

feralkid
02-12-2012, 01:44 PM
I can honestly say that everyone I have sex with always smokes after!

Then again I am the furnace operator at the crematorium.

That was unexpected.

:D

Yzzim
02-12-2012, 01:57 PM
Not trying to hijack this thread, but..

My furnace seems to run about every 10 minutes as well, at least that once the temp gets below 20-30 degrees.
My house is 1500 sqft (main level) with about 1000 sqft basement (partially finished, heated).
The furnace is about 50,000 btu which seems small to me...it looks small too. It is a newer model, high efficiency furnace. Haven't been able to pinpoint a date exactly, but I'd say it was installed in the early to mid 90s.

Anyway to tell if the furnace is the correct size? If so, would having a furnace that is too small make it less efficient? Would it cost more to run or does it just mean it would run longer but heat the same?

edro
02-12-2012, 03:46 PM
Dead Band is another term for hysteresis.
If your set point is 70, a 4 dead band would mean the heat would turn on at 68, or AC at 72.

Zedtom
02-12-2012, 03:53 PM
My first house had a crawl space where the furnace was located. It would run for ten minutes then cycle off and come back on for ten minutes all night long on cold nights. It was driving me crazy. There was a house inspection the summer before when I moved in, and the furnace had been checked out and passed.

The problem was two ducts had cheap duct tape and had loosened up and air was pouring out heating the crawl space. It looked like the previous owner or somebody had tampered with them to make it loose.

I bought some metal pro grade duct tape and sealed them up and enjoyed a lower fuel bill.

Modelworks
02-12-2012, 03:57 PM
Make sure there is not a vent blowing in the direction of the thermostat. Sometimes air flow bounces off objects and when blowing across the thermostat will trigger it off, air flow stops, thermostat temp now lower cuts back on.

Another trick you can use is one of those boxes that cover the thermostat to block some of the room air from accessing the thermostat so quickly

Modelworks
02-12-2012, 04:01 PM
My house is 1500 sqft (main level) with about 1000 sqft basement (partially finished, heated).
The furnace is about 50,000 btu which seems small to me...it looks small too. It is a newer model, high efficiency furnace. Haven't been able to pinpoint a date exactly, but I'd say it was installed in the early to mid 90s.

Anyway to tell if the furnace is the correct size? If so, would having a furnace that is too small make it less efficient? Would it cost more to run or does it just mean it would run longer but heat the same?

It depends on the climate where it is installed. Florida would have no problem with a unit that size while New York it would be way undersized. I had a home that had a 3 ton unit and the home was under 1000 Sq. ft which is over sized but the dealer had it from another customer order that canceled and sold it the same price as the correct sized unit . My utility bill never broke $100 in summer or winter because the unit barely had to run , oversized is definitely better if the price is right.

A ton is about 200,000 BTU. So your unit isn't even 1/2 ton, a small unit.

JEDI
02-12-2012, 04:21 PM
Recheck your settings. Also the type of heating system (hot water baseboard or hot air) and wether it is a newer high efficiency furnace will have to use the correct settings.

Set to 5 if you have gas or oil furnace ... this would be for normal, old hot air furnace
Set to 9 if you have electric furnace .. not many homes have this type
Set to 3 if you have hot water or high efficiency furnace .. hot water baseboard heat or new high efficiency furnace
Set to 1 if you have gas/oil steam or gravity system ... only used if you have steam radiators found in many very older homes

Note you can check the nameplate on the furnace. If it is within say 4 years or so old and has a rating of 80% or higher, it is a high efficiency type of unit.


wait.. 80% is high efficiency?!

and would the name plate specifically say "high efficiency?"

bobdole369
02-12-2012, 06:09 PM
What the hell is a furnace?

LiuKangBakinPie
02-12-2012, 06:16 PM
What the hell is a furnace?

Its like hell but only smaller

Rubycon
02-12-2012, 06:18 PM
A ton is about 200,000 BTU. So your unit isn't even 1/2 ton, a small unit.

Tonnage is associated with refrigeration and comes from number of tons of ice that could be made in a 24 hour period. 12,000 btu/hr is one ton.

A common size for a household AC unit is three tons - 36,000 btu/hr.

Heating usually is much higher whereas a home may need three tons of AC the furnace may have 100,000 btu/hr. That is actually the INPUT so if the furnace is 80% efficient the actual heat directed into the home would be 80,000 btu/hr.

Rubycon
02-12-2012, 06:24 PM
What the hell is a furnace?

Perhaps this will help.

http://www.youtube.com/watch?v=TzKxTFsXcyc

:biggrin:

Bignate603
02-12-2012, 06:24 PM
Seems to me it'd be more efficient to try and keep at a constant temperature rather than losing all that heat during the day and trying to make it up in the evening.

It's not. The amount of heat (in BTU) that moves out of a warm house in a given amount of time is significantly greater than the amount of heat that moves out of a cool house. It's because the difference in temperature between outside and inside has a very large effect on the rate that you lose heat from the house. For a very simple analogy you can think of that difference in temperature as the "pressure" causing the heat to leave the house. The higher the difference in temperatures the higher that "pressure" is and the faster the heat leaves.

When you turn up the heat after the house has cooled down the furnace will have to run for a long period to get the house back up to temperature. However the total amount of heat it will need to produce to heat back up the house will be far less than it would have taken to keep the house warm the whole time.

LiuKangBakinPie
02-12-2012, 06:25 PM
Tonnage is associated with refrigeration and comes from number of tons of ice that could be made in a 24 hour period. 12,000 btu/hr is one ton.

A common size for a household AC unit is three tons - 36,000 btu/hr.

Heating usually is much higher whereas a home may need three tons of AC the furnace may have 100,000 btu/hr. That is actually the INPUT so if the furnace is 80% efficient the actual heat directed into the home would be 80,000 btu/hr.

cooling capacity of air conditioning equipment

Imp
02-12-2012, 06:54 PM
To answer your other question, yes, it saves energy. Your house loses energy at a rate proportional to the difference in temperature between indoors and outside.

IIRC (and don't really...), the equation for heat loss has the cube or square of the delta-T on one side of the equation. Oh shit, I don't remember. Thank god I did half my masters on it.

So, where is OP's thermostat located? Mines is behind my computer, just about a foot above my monitor's CFL backlight... Keeps the thermostat nice and toasty....

mattpegher
02-12-2012, 07:19 PM
sounds like its short cycling, The last time mine did that was because it was overheating and shutting off prematurely. I had a repairman come out and test it. He cleaned the units gas vents and that fixed the problem.
I have also heard that some HEPA filters will cause some units to short cycle because of over heating.
If its an older unit it may just need cleaned.

Red Squirrel
02-12-2012, 07:23 PM
sounds like its short cycling, The last time mine did that was because it was overheating and shutting off prematurely. I had a repairman come out and test it. He cleaned the units gas vents and that fixed the problem.
I have also heard that some HEPA filters will cause some units to short cycle because of over heating.
If its an older unit it may just need cleaned.

That's a good point too. It may be the furnace itself.

OP: When the furnace stops, is the temperature at what it should be? Also, you should hear the relay in the thermostat go click for going on or off. Does this correspond with the furnace going on or off, or is the thermostat always in the on position and the furnace still going on/off?


Speaking of thermostats, this (http://www.redsquirrel.me/2012/01/21st-century-hvac-control.html) is a little project I've been working on. More blog entries after that one. Overkill thermostat ftw.

iGas
02-12-2012, 09:59 PM
That's a good point too. It may be the furnace itself.

OP: When the furnace stops, is the temperature at what it should be? Also, you should hear the relay in the thermostat go click for going on or off. Does this correspond with the furnace going on or off, or is the thermostat always in the on position and the furnace still going on/off?


Speaking of thermostats, this (http://www.redsquirrel.me/2012/01/21st-century-hvac-control.html) is a little project I've been working on. More blog entries after that one. Overkill thermostat ftw.
Look like a great project, but making things more unreliable by complicating things. Most new commercial/industrial HVAC system are now centralize control via the internet, and I haven't seen anyone apply this method for residential dwelling (even on 20+ millions dollar house/structural only).

postmortemIA
02-12-2012, 10:33 PM
Its like hell but only smaller
:biggrin:

cbrsurfr
02-12-2012, 11:43 PM
Is it just the fan coming on every 10 min? My furnace has a circulation setting, which cycles the fan on between heat cycles, it's a 10 min default setting. I can set it to auto, circulate, or on. My furnace is much newer though.

BoomerD
02-13-2012, 12:14 AM
Looking at the manual:
http://customer.honeywell.com/techlit/pdf/PackedLit/69-2416ES.pdf

System Type
Function 1
0 Heating & cooling: Gas, oil or electric heating with central air conditioning.
1 Heat pump: Outside compressor provides both heating and cooling without backup or auxiliary heat.
2 Heating only: Gas, oil or electric heating without central air conditioning.
3 Heating only with fan: Gas, oil or electric heating without central air conditioning. (Use this setting if you could turn the fan on and off with a fan switch on your old thermostat.)
4 Cool only: Central air conditioning only.
5 Heat Pump: Outside compressor provides both heating and cooling with backup or auxiliary heating.
6 Heat/Cool Multiple Stages: Two heat stages (wires on W and W2), two cooling stages (wires on Y and Y2).
7 Heat/Cool Multiple Stages: Two heat stages (wires on W and W2), one cooling stage (wire on Y).
8 Heat/Cool Multiple Stages: One heat stage (wire on W), two cooling stages (wires on Y and Y2).

If you have a furnace and A/C, it should be set at "0."
Just a furnace w/o A/C, it should be set at "2."
If you have a heat pump, then it should be set at "5."


Fan Control
Function 3
0 Gas or oil heat: Use this setting if you have a gas or oil heating system (system controls fan operation).
1 Electric heat: Use this setting if you have an electric heating system (thermostat controls fan operation).

Heating Cycle Rate
Function 5
5 Gas or oil furnace: Use this setting if you have a standard gas or oil furnace that is less than 90% efficient.
9 Electric furnace: Use this setting if you have any type of electric heating system.
3 Hot water or high-efficiency furnace: Use this setting if you have a hot water system or a gas furnace of greater than 90% efficiency.
1 Gas/oil steam or gravity system: Use this setting if you have a steam or gravity heat system.

It's possible that you have something wrong in the initial settings...OR, you could have connected your wiring wrong. Double check that.

bobdole369
02-13-2012, 12:47 AM
Perhaps this will help.

http://www.youtube.com/watch?v=TzKxTFsXcyc

:biggrin:

LOL <3 that movie! Haven't had a furnace in my house since I lived in the great white north (SEMICH). Florida homes don't need such nonsense. Currently 55f - and everybody puts on ugg boots, fuzzy hats, sweaters, actual coats, gloves, etc. You'd think it was a massive snowstorm. I had a hoody, trapper hat, and shorts on today. :)

OrByte
02-13-2012, 12:58 AM
good luck OP I am researching practically the same problem for my house that just popped up today

bruceb
02-13-2012, 07:52 AM
Based on this info from Boomer and the OP saying it is a 20 year old furnace the OP should set
the Heating Cycle Rate as listed below


Function 5
5 Gas or oil furnace: Use this setting if you have a standard gas or oil furnace that is less than 90% efficient.

Modelworks
02-13-2012, 08:09 AM
Speaking of thermostats, this (http://www.redsquirrel.me/2012/01/21st-century-hvac-control.html) is a little project I've been working on. More blog entries after that one. Overkill thermostat ftw.

I did a similar project about 2 years ago. The thing I wanted to change was how my thermostat would turn off the AC when the room temp was reached . I noticed that when it did this there was still plenty of coldness to the air exchange unit so it was just letting that go to waste. I wired it so that when the temperature was reached it would turn off the compressor but proceed to blow air until the air exchange itself was no longer cold. Later I was able to predict how long it took for the air exchange to use up whatever cold it had stored and add that to the program so the thermostat looked for what the temp would be with the added blower run time allowing the compressor to shut off earlier than a plain thermostat control. I save quite a bit off doing that project. I used a pic controller, 16f84 I think, DS1822 temp sensor, and a relay for the switching.

JEDI
02-13-2012, 02:42 PM
Based on this info from Boomer and the OP saying it is a 20 year old furnace the OP should set
the Heating Cycle Rate as listed below


Function 5
5 Gas or oil furnace: Use this setting if you have a standard gas or oil furnace that is less than 90% efficient.

wait.. u said 80% above?! now 90%?

wtf?

Triumph
02-13-2012, 10:43 PM
Based on this info from Boomer and the OP saying it is a 20 year old furnace the OP should set
the Heating Cycle Rate as listed below


Function 5
5 Gas or oil furnace: Use this setting if you have a standard gas or oil furnace that is less than 90% efficient.

Yes I said that early in the thread, that's what it was set at when it was turning on every 10 minutes. I changed it to setting 3 for "high efficiency" furnace. Which I seriously doubt that I have. But it seems to have fixed the problem, it took over 25 minutes between cycles this time, and the indoor temperature reading has not dropped yet.

I still think it's a shitty thermostat for not making this more clear in the instructions.

millermin
11-24-2014, 11:43 AM
Yes I said that early in the thread, that's what it was set at when it was turning on every 10 minutes. I changed it to setting 3 for "high efficiency" furnace. Which I seriously doubt that I have. But it seems to have fixed the problem, it took over 25 minutes between cycles this time, and the indoor temperature reading has not dropped yet.

I still think it's a shitty thermostat for not making this more clear in the instructions.

I got same problem this season,and i did the same job as you after read this, and fixed the same problem, thanks a lot.

gorcorps
11-24-2014, 04:07 PM
despite the necro, this is still valid:

I've got to dig it up again, but I remember reading a study on the difference between letting your heat (or AC) run all day vs. right when you come home. Their conclusion was it was better to save energy during the day, and run it longer right when you get home after some real world tests.

The theory behind why IIRC is because your house is obviously not perfectly insulated, so it's going to be losing heat during the day. Heat transfer is greater when your delta T is greater (difference in temperature), so the bigger the difference between the outside temperature and the temperature you're heating your house to, the larger your heat transfer rate. So by keeping your house warmer for longer, you're wasting more heat via natural heat transfer than you would if you kept it cooler when you aren't there.

Red Squirrel
11-24-2014, 04:20 PM
despite the necro, this is still valid:

I've got to dig it up again, but I remember reading a study on the difference between letting your heat (or AC) run all day vs. right when you come home. Their conclusion was it was better to save energy during the day, and run it longer right when you get home after some real world tests.

The theory behind why IIRC is because your house is obviously not perfectly insulated, so it's going to be losing heat during the day. Heat transfer is greater when your delta T is greater (difference in temperature), so the bigger the difference between the outside temperature and the temperature you're heating your house to, the larger your heat transfer rate. So by keeping your house warmer for longer, you're wasting more heat via natural heat transfer than you would if you kept it cooler when you aren't there.

That's pretty much what my theory has always been, nice to know that it's actually backed up by some studies. I never really tested it myself.

I let the heat drop to like 12c at night or when I'm not home. When it does kick in it runs till it hits about 15c then lets it drop to 12 again. I set a long range like that mostly so that the heat runs long enough that it should get to areas that are colder than 12. In -50 situations I don't want pipes to freeze.

What sucks though is when I need to get up to go pee in the middle of night. :P

JEDI
11-24-2014, 04:24 PM
Yes I said that early in the thread, that's what it was set at when it was turning on every 10 minutes. I changed it to setting 3 for "high efficiency" furnace. Which I seriously doubt that I have. But it seems to have fixed the problem, it took over 25 minutes between cycles this time, and the indoor temperature reading has not dropped yet.

I still think it's a shitty thermostat for not making this more clear in the instructions.

ok, how do I set my furnace from a 5 to a 3?

gorcorps
11-24-2014, 04:35 PM
Yes I said that early in the thread, that's what it was set at when it was turning on every 10 minutes. I changed it to setting 3 for "high efficiency" furnace. Which I seriously doubt that I have. But it seems to have fixed the problem, it took over 25 minutes between cycles this time, and the indoor temperature reading has not dropped yet.

I still think it's a shitty thermostat for not making this more clear in the instructions.

They must not have paid their technical writer enough

natto fire
11-24-2014, 06:35 PM
why 3?

changing from 5 to 3 will increase sensitivity, thus more cycles?

Yeah, I was going to suggest going the other way, setting it to 9, although it might end up making the temperature swing too much to be comfortable.

Carson Dyle
11-24-2014, 07:19 PM
If you can't figure out which is which, try one extreme, then the other. Shouldn't take someone of average intelligence very long to figure it out.

("Hey, if I can't find the knowledge on the Internet, I'm f***ed.")