I've written before about my system that keeps running without shutting off. Climatemaster Tranquility 4 ton closed loop in Indiana. Heating downstairs only -1600SF- of an 1830's brick federal. Contractor was out again today and slowed down the air speed to make it hotter. Also switched Honeywell stat with a White Rogers Big BlueUniversal stat 1F95-1291. While here, all looked like that was the answer. The system cycled on and off around 15 minutes at a time at setting of 67. Outside temp was 28. This continued until we settled in for the evening and turned the temp up to 69. It has once again kept running for over five hours now merely cycling between stages 1 and 2. The reading of the inside temperature is 69, too. The outside temp is 20 or so. Any ideas about solutions to this problem? Is it a problem? Thank you for your thoughts and expertice.

Unless stairway(s) have doors you are probably somewhat heating upstairs as well.

Old house - loose (high infiltration) and not much insulation?

Slowing blower to make air hotter costs both capacity and efficiency. How hot was the air and how hot is it now?

Do you have auxiliary resistive strip heat? - sounds like you are going to need it later this winter.

Systems in indiana are usually designed with a balance point of around 25 degrees to 30 degrees out door temperature. At this point the system will run 100%. If you have a Tranquility 27, because of the 2 stages It will run 100% at a much higher temp but on low stage. This is a good thing. If it is not running, it is not saving you money. It is like a car cruising on the highway. That is where it gets its best economy.

Klatunickto:
I went back and read all your posts. You had the same problem in October when outside was 42 degrees. Your system kept running for hours.

Based on what you have posted and what I know, two cases come to mind:
1- Your system was running at 2nd stage or perhaps near max capacity, as Engineer and IndyGEO implied above.
2- Some thing is going on with the tstat.
I would think, but I am not sure, that No 1 is not the case, as the problem existed when it was 42 degrees outside. But since then the ambient and ground loop temps have changed. Perhaps you can rule out the capacity limit concern by gradually increasing the setpoint to 73 degrees, one degree at a time, to find out if your heat pump will maintain the higher demand, without activating aux heat. Your new stat will activate the 2nd stage of the compressor if you set it 3 degrees higher than the current room temp. If you do this test, please note the stage of compressor (indicated on stat), outside temp, and the time it takes if and when each new level is reached.

For my No 2 concern, I looked at your new thermostat's manual online. It is complex. With all indoor / outdoor sensors, fast / slow cycle rate selections, and a lot of other settings, here I think of humidity. I am not certain if Tranquility can start to dehumidify between heating cycles, due to the thermostat (either installer or user defined) settings. Early on with my Tranquility 27, the fan (while was set on auto) started to run continuously when indoor humidity dropped, as it got cold outside. I do not have a humidifier, but the humidity sensor of tstat was calling for humidity increase, thus turning on the blower. I lowered the humidity setpoint on the thermostat to min and above the room's, the blower stopped.
Could this be your case? You wrote "It has once again kept running for five hours now merely cycling between stages 1 and 2." Did you see "System On +2" lit on the tstat indicating the 2nd stage was running? Or did you notice a change in the system sound and the blower force as it would have cycled between 1st stage and a lower fan only speed?

What was the installers logic for slowing down the air speed? Was "cool air coming out" one of your complaints?

Regards, Masoud

Thanks to all responders. The temperature at the registers was mid 70's. Slowing it down a bit took it to mid 80's according to the trouble shooter who has been out the past two days. It is mid 20's with 15-20 mph winds currently. Stat has been maintaining at 70 in 2nd stage for many continuous hours. I checked the humidity setting and it was on 5. I could not get it to go lower so I assume that that is the minimum. I also tried Masoud's test with raising the temperature without favorable results; however, I will save that same test for next week. After talking on the phone a few minutes ago to the technician, thay are going to move the stat to a different room on Monday. They have never thought this would have helped, but if you have read my post back in October, you know that I have been suspicious all along of its placement at the base of the stairwell with the unheated landing above. The stat is on the wall right above  the air return. It is so drafty that I have felt that it had to be the reason that it reached setting but never shut off. I don't know that they even now think that is the problem, but that they will at least appease me since nothing else is working. I will post an update early next week.

Whether the system is gas , oil , or geo All two stage equiptment is designed to run most f the time in 1st stage in the peak heating/cooling times.  This is a comfort issue. Second stage is to catch up if 1st stage does not satisfy a maintaining temperature status.Aux is also a catchup if 1st and 2nd stg doesnt satisfy the setpoint. If you notice, the eqiptment may run and run in 1st stg , then after 10 min or so , 2nd stg will kick on in increments then back to 1st stg.

 

on another note , if you have 70 degree indoor temp, i would hope you have supply temps in the low to mid 90's for 1st or 2nd stg geo   

If possible measure return air temp as near as possible to the unit, such as at the filter. Be careful that taking the measurement doesn't influence it such as by opening the return air to unheated basement or garage air while thermometer is in place - best might be an inexpensive LCD outdoor thermometer with a probe on a wire.

If it is significantly below house interior temp that indicates return air being pulled from unheated areas and would help explain both continuous / lengthy run times and tepid supply air (and the resulting high power bills)

Klat,

You emailed me that you are seeing a 13 deg F drop (65 down to 52) between main return and air filter - that's huge, given that the typical heating TD is only 20 or so. What's likely happening is that some very cold air is getting sucked into and mixing with the return air between the main return and unit. We are up against a failing of the internet - I can't hang my head into your return ductwork and determine the problem. Another possibility is that you have a long run of uninsulated return ductwork in cery cold unconditioned space, or, heaven forbid, outside.

Your installing contractor needs to step up and deal with this. I'm glad I was able to point you at the problem, at least.