Furnace turns on every 10 minutes

[waggy]

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]

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.

 

[Yzzim]

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]

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]

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]

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]

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]

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]

What the hell is a furnace?

 

[LiuKangBakinPie]

What the hell is a furnace?

Its like hell but only smaller

 

[Rubycon]

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.

 

[Bignate603]

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.

 

[Rubycon]

What the hell is a furnace?

Perhaps this will help.

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

:biggrin:

 

[LiuKangBakinPie]

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]

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]

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]

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 is a little project I've been working on. More blog entries after that one. Overkill thermostat ftw.

 

[iGas]

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 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]

Its like hell but only smaller

:biggrin:

 

[cbrsurfr]

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]

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]

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]

good luck OP I am researching practically the same problem for my house that just popped up today

 

[bruceb]

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]

Speaking of thermostats, this 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.