Honeywell Thermostat Cycle Time

[noisyattic]

Installed a Honeywell programmable thermostat. Problem is that it cycles on and off at least six times an hour, approximately 5 minutes on/ 5 minutes off. It's driving me crazy since the furnace for the second floor is in the attic, and it's loud. Went to the FAQ's at Honeywell and it states:

"cycle rate is the ideal number of times a heating system will run, in an hour, to maintain temperature within one degree. For instance, gas or oil forced air systems have a recommended cycle rate of 6. With a cycle rate of 6, the heating system, at a 50% load, will cycle 6 times per hour. This breaks down to about 5 minutes on and 5 minutes off. Again, the actual on and off time of the heating system will vary as the load on the heating system varies."

Is this true? Seems like a lot to me.

Thanks

[bmbradley]

I had the same problem with a Honeywell programmable
thermostat I paid close to $100.00 for. Some times
it wouldn't run the oil burner, (forced hot air),long
enough for the limit switch to even start the blower
motor then shut off satisfied. I installed a good quality
White Rodgers t-stat and never had another cycling problem. Quality has gone down hill real fast in the last few years.

[mayguy]

You can change the cycle per hour.. Look in the owners manaul.. I would set it to 3 cycle per hour..

[whitedog]

You may have a Honeywell Chronotherm thermostat that has 2 cycling settings: 6 cycles per hour and 3 cycles per hour. I downloaded installation instructions from Honeywell's website and discovered how to set it to 3 cycles per hour. 10 min on and 10 off.

[hvacfella]

In my travels, Ive noticed the cheaper Honneywell Electronic Programmable thermostats sold in Menards and Home DePot (especially the Model 'CT' series)...will drastically short cylce the furnace -- especially if the furnace is an 80 or 90 plus unit ; its too bad Honneywell doesnt give the operator a specific "Temperature Differential" to choose from (IE : 1 degree, 2 degree, or 3 degree) . Thats why i prefer Robertshaws SaverStat model , over Honneywell .

[drumn91]

I have had bad experiences with Honeywell thermostats, especially the Magic Stat like mentioned above as a cheap Menards and Home Depot thermostat. I have installed thousands of White Rodgers thermostats and have had the least callbacks from them and they are the longest lasting. Check out the 1F 86 series. Best bang for the buck. Stay away from Honeywell......Home Depot, Wal-Mart,Menards,Kmart,Ace Hardware.....you wont find White Rodgers there and there is a reason for that...Honeywell has given in to greed and quality controls as well as quick testing on new products in their R & D labs, manufacturing enough to meet the demand of the HVAC dealers as well as every frickin store in the country..Robertshaw is not bad either.

[noisyattic]

Thanks for the advice. I'll be replacing this thermostat soon.

[Shophound]

In fairness to Honeywell, the VisionPro thermostat is a quality product. I've also had good experience with the "Vision" stat sold at Lowe's, as it's essentially a VisionPro with less features but the same basic performance.

[jerrod6]

A few years ago I had a Trane programmable stat installed with my Trane system. I think it was set to 3 cycles per hour, but it was adjustable. This year I had my HVAC pro install a Honeywell Vision Pro. For the type of system I have it was set to 5 cycles per hour, but it too is adjustable. Right now it is set to 4 cycles per hour.

I personally can’t stand room temperature fluctuations so I do not want the room temp to fall more than ½ degree or less, but I don’t want to unnecessary wear on the system, so there is always compromise to be made. In the winter I have the thermostat set to 71 degrees. Summer it is set to 73 degrees.

At 4 cycles per hour in mild weather(40 degrees) I will get run times of 7 min on and 8 min off for a while and then sometimes the unit will not be on for 30 to 40 minutes. When it gets a bit cooler (low thirties) the times increase to perhaps 9 on and 9 off. When the temps are single digits to teens, the times are any where from 23 to 27 minutes on, and 6 to 7 to 10 minutes off, I think some of this depends on the conditions in the house like wall and furniture temperature as well as air temp.

I have no problem with my Honeywell vision pro and it actually helped to reduce the cooling bill a bit, but I would encourage people to get stats that have adjustable cycle rates. That way you can have it adjusted to meet your needs.

As for buying at Lowes or Home Depot, well, I am not qualified to comment on that, but I feel that since I have made a major investment in my HVAC system and I have a good relationship with my HVAC service pro I would rather have him take care of everything. He knows what he is doing and I don’t have to.

[ckr74]

I really like the Visionpro. I have one on my wall, but I'm not real sold on it. It is neat looking though. But ya know,I almost miss my White-Rodgers. Seemed like it regulates temp better and more consistant. I think it's lots easier to program. More user friendly than the Visionpro by far. Just my opinion though. Later!

[mayguy]

CKR,

How is that WR regulate the temp better than the Vision?

I have the Vision, and I'm very happy with the temp control. it stays with in range. and all room is comfy..

What do you have yours set up at for cycle per hour?

[hvacfella]

'I personally can't stand room temperature fluctuations so I do not want the room temp to fall more than ½ degree or less, but I don't want to unnecessary wear on the system
'

ME: A half degree is simular to Laboratory conditions ; you will cycle the death out of your equipment . Its unnecessary ; most people are comfortable at a 2 f. differential unless you are sitting still for a long time without much on . Id encourage you to experiment at going with the widest differential you possibly can for sake of equipment longevity and fuel costs. If you dont have a humidifier, that will help as well.

[noisyattic]

I have the same Honeywell thermostat for the downstairs furnace too. I didn't want to have to replace the downstairs thermostat so I called Honeywell today to find out if I could change the cycle rate. Turns out for my model the options are cycle rates of 1,3,6 or 9 cycles per hour. There's no option for setting it for a fixed temperature differential. I was advised not to lower the cycle rate from 6 for a furnace below 90% efficiency because, I paraphrase, "the furnace should not run much longer than the 5 minutes at a time because it was hard on the equipment especially the burner." He also said that it was more efficient to run the furnace more frequenty but for shorter periods.

What do you make of that? It seems that the constant cycling on and off would be worse. Opinions?

Thanks again.

[hvacfella]

'I paraphrase, "the furnace should not run much longer than the 5 minutes at a time because it was hard on the equipment especially the burner." He also said that it was more efficient to run the furnace more frequenty but for shorter periods.
What do you make of that? It seems that the constant cycling on and off would be worse. Opinions?
Thanks again
'

ME: If Honneywell told you this, then, im mighty surprised ; Running the furnace more frequently for shorter periods...might afford you the greatest amount of comfort, BUT, it will come at an expense --- both to the equipment life and fuel consumption. What you want to do , is, to experiment with the cycle rate of the thermostat until you achieve close to a 2 degree f. drop in room temp. before the next furnace cycle starts ; whatever a 2 degree F. drop equates to in terms of 'cycles per hour' , is where you should set it. This way, youll achieve satisfactory comfort and not short cycle the furnace excessively. (Bear in mind, that, you may need to make a periodic adjustment to this as the outside temp. gets significantly colder/warmer thruout the winter ).

[jerrod6]

Two questions:

1. As I mentioned in my first post I have the Vision PRO that is set for 4 cycles per hour for the 1st stage of heat. The installation manual gives a range of typical cycles per hour based on the type of system you have. It recommends

1 cycle for steam, 3 cycles for hot water or 90% forced air system, 5 cycles for forced air systems under 90% and 9 cycles for electric forced air systems.

Does anyone know why 3 cycles is recommended for 90%AFUE and above and 5 is recommended for below 90%?


2. Why would you have to muck about with the number of cycles when the outside temperature gets warmer or colder?

[Shophound]

I wouldn't tweak with the cycle rate per hour based upon outdoor temp changes. I'd find a cycle rate that works well for normal cold weather and leave it at that.

On my own VisionPro I've lowered the cycle rate for my Trane 80% from 5 CPH to 4. This gives a longer interval between calls for heat and allows for a slightly higher temp drop before the stat calls for heat, which translates to slightly longer run times for the furnace. That in turn means more comfort and less stress on the equipment, along with fuel savings as the furnace isn't constantly bumping on and off.

The previous owners of our house oversized the furnace and a/c, anticipating finishing out a garage conversion, which they never did but I've since done. Even so, after running a heat calc on the house I'm a ton oversized in cooling and could do fine with a 50 vs. a 60k BTU furnace. Just goes to show the size-by-thumb method is bogus.

[jerrod6]

Shophound:

I also have a Trane 80% 2stage VS and the Vision pro. I had the cycle rate lowered from 5 to 4 in November and so far everything seems to be ok.

I was just wondering why the Trane installation sheets would recommend 3 cycles for 90% or better, but 5 cycles for below 90%?
What kind of difference does this cause because the efficiency is lower?

Last week the temp was in the single digits and I had good long run times. And sometimes less than 4 cycles per hour. This week it is in the mid to upper 40’s. The system runs a bit to recover from set back, and then may not run for 5 or 6 hours, so I really didn’t see the need to move the cycle rate all the time. With the VS blower I keep it set to “on” during the heat periods to distribute the heat from the upper floors throughout the house, so maybe that accounts for the long off times when the weather is mild.

[furnace doctor]

I have read a release from Honeywell that shows that their thermostats use tri-ads(voltage stealing) boards and they are having problems with furnace boards. To use these thermostats you needed a resister accross the terminals.
I just started using the White Rodger that didnot use that type of board.