Regarding not reaching 70, I assume that the average temperature dropped in the house due to in=and-out activity that might also tend to distribute the mass of cold air from our less insulated rear porch. The next scheduled event is back down to 62 at 8:00 a.m. I couldn't find the American Standard install manual online, but the same thermostat is available from Trane. I have excerpted what I think are the relevant controls to play with. I did look at these once, but was frankly too put off by all the double negatives such as, "disables the 10 minute inhibit" and "Heating Aggressive Recovery can only be enabled if Aggressive Recovery is disabled." I'll be back home in two weeks and I can try to adjust these. Naturally, I will ask for advice here on anything I'm unsure of. Aggressive Recovery: This option disables the 10 minute inhibit anytime the thermostat sees more than a 2° change (such as moving from one program time frame to another). This applies to heating & cooling modes. Heating Aggressive Recovery: This option disables the 10 minute inhibit based on outdoor temperature in heating mode only. The value for outdoor temperature can be set from 0°��"70°. Heating Aggressive Recovery can only be enabled if Aggressive Recovery is disabled.There is a 10 minute “inhibit” period between first and second stage compressor as well as compressor heating & supplemental strip heat. This 10 minute inhibit period minimizes the cycling of higher capacity request due to drafts around the thermostat or marginal load conditions. Cycle Rate The cycle rate affects the cycle time of the system. With a 50% load value, a cycle rate of 3 will allow the system to run for 10 minutes and be off for 10 minutes; completing 3 cycles in one hour. A cycle rate of 5 would allow the system to cycle on and off at 6 minute intervals. The higher the cycle rate, the more often the system turns on and off. The actual amount of time the system will be “on” or “off” will be reflective in the load value of the home. Higher load value demands will increase system run time and decrease system off time. Lower load value demands will decrease system run time and increase system off time.Emergency HeatThe heat pump will be disabled and the furnace / heat strips are enabled any time the thermostat is set to Emergency Heat. Lockouts System lockouts will disable a certain function of the system under specific outdoor temperatures:Compressor Heating Lockout • ��" will lockout all compressor operation below a set outdoor temperature (from 5°��"70°). This value must be set lower than the auxiliary heat lockout. Auxiliary Heating Lockout • ��" will lock out auxiliary heat stages above a set outdoor temperature (from 40°��"70°). This value must be set higher than the compressor heating lockout. Defrost Heater Balance Point • for W1, W2 & W3 ��" will lock out specific auxiliary heat stages when above a set outdoor temperature. (W1 setpoint is from 40°��"55°, W2 & W3 setpoints are from 5°��"55°). This feature does not apply to dual fuel systems. Compressor Cooling First Stage Lockout • ��" will lock out the first stage compressor above a set outdoor temperature. (from 80°��"120°) Compressor Heating First Stage Lockout • ��" will lock out the first stage compressor below a set outdoor temperature. (from 0°��"50°) Furnace First Stage Heating Lockout • ��" will lock out first stage furnace operation below a set outdoor temperature. (from 15°��"50°) First stage lockouts are not available with zoning. Setpoint Dead Band This sets the temperature band between heating and cooling setpoints while in the auto mode. Here is a link that might be useful: Trane Comfortlink II Installation Manual

I ask this because it happened to me.....is there something close to the Tstat that generates heat during the day, causing the Tstat to read as satisfied even though the rooms temperature feels lower during the day than at night? Our Tstat was on a wall in the living room, and the TV was close to the wall. We have the TV on frequently during the day. House always felt one temp during the day, and then warmer at night. Finally we realized that the TV was putting out heat and that was raising the temperature close enough to the Tstat to have it read as satisfied at the set temp, even though the actual room temp was lower. So the boiler was not very active during the day. Then at night with the TV off, it was very active. Something like that may be happening to you. Additionally, your older home probably has more infiltration at the basement (I am guessing it is stone and does not have insulation and a vapor barrier...) and has more cold air seeping in there. This may be mixing with the air in your first floor where the Tstat is located, and would be a colder air mix at night when outdoor temps are lower. Combine that with the hot air in your home rising during the night, and that may explain some of the temperature stratification you experience. Have you actually checked the temperature at the radiators themselves in the day and middle night to see if they are vary by different amounts day/night? Do you have a one-temp type of Tstat, or a programmable one? Either way, try dialing it back a bit when you go to bed and see what happens. (but you will be cold at 6am!)

Ok,I misstook the air inlet pipe for a motor housing. You are correct,no motor is involved. Despite your dodging the volt meter,I will try to help you. And please,if anyone here on G.W. knows by looking at the pics what the problem is, spare mamalinda the hassel of testing. First off,the symptoms point to a loose or broken wire or t-stat. You stated "I've replaced the batteries in the thermostat and looked at all the wiring - nothing seems to be loose or breaking." , that must be 100% true or our tests will be flawed. One pair of the wires connected to the blue plastic is from t-stat ( we will call them T and Tc ) and the other pair go's to the pilot lite ( we will call them P and Pc ), We know that Tc and Pc are the 2 wires in the center, The wire on end that go's to pilot is called P which leaves the wire on opisite end as T. Turn t-stat on and calling for heat. Touch one lead of volt meter/test light to either center screw and other lead to an end screw then other end screw. Tell us: A. If you got readings and which end screws had a reading ( YOUR RIGHT, LEFT or both) B. If each pair of wires remain within the same outer jacket as they go from blue plastic to pilot and t-stat. Or conversly,if one wire within a jacket terminates at pilot and other terminates at t-stat. When we have your answers,we will continue from there. Note on meter, if needle deflects backwards when screws are touched, reverse leads because -- & + are reversed. A digital meter will simply read as a negitive voltage if leads are reversed. Note on test light, note voltage on one of the batteries and multiply voltage by the number of batteries in t stat. That is the volt value your test light must be within 10% of.

Thanks Racket. The heater has sprung back to life. I disconnected and sprayed WD40 into the connectors to the control display board and the blue spark ignitor wire and she's working again. thanks for the help. regards