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Data Logging Thermostats

Home Inspector Training

Heat Pump Defrost

HVAC System On or Off when Unoccupied?

Learning HVAC Controls

Honeywell Chronotherm Plus 8624D Thermostat Problem

Twinned Split System with a Single Air Handler

Data Logging Thermostats

1) Question: Is there a thermostat for a nursing home with a print out for temperature verification? There are a few options for you. The answer......

Home Inspector Training and High Performance HVAC

2) Thank you!! I am training to become a home inspector and the info contained on this site is helpfull in identifing issues that require a HVAC professional to resolve. Read more........

Heat Pump Defrost

3) Hi. I noticed my that one of my outside condensing units was laboring throughout the night. This morning I found ice/frost buildup on the radiator fins. I live in Tucson, Az. It has been colder than normal (below freezing) with a bit more moisture in the air than usual as of late. Can you please tell me what causes this frost/ice buildup, and how I go about rectifying? Does this mean that the condensor pump is shot? I'm originally from the midwest, and have never experienced this before. What should I be doing? Thank you for your help. The answer...............

HVAC System On or Off when Unoccupied?

4) Please confirm this advice if you would; it is better to have your thermostat left at 70 to 72 degrees during the day while your home is empty and adjust accordingly when you get home as opposed to shutting off the heater/ac and turning on when you get home. I would think this would put less strain on the unit. Thanks in advance for your help. The answer.......

Learning HVAC Controls

5) I want to learn about BAS and DDC. The answer..........

Honeywell Chronotherm Plus 8624D Thermostat Problem

6) I have a Honeywell Chronotherm Plus 8624D running a Trane XL19i with a Trane XV90 - all installed new in new construction in 2003. Every winter, during the morning warmup from 66 to 70, the burners stays on for approx 1.5 hours at 70, then rises quickly to 73 before finally shutting off. The only way to interrupt the process is to turn the system to OFF at the theromostat. The system is on AUTO with the cooling set at 75 for the winter. I have swapped the thermostats (there are two sets in the house, this is the one in the attic for the second floor) with the same results. I have not swapped the thermostat circut boards, but I can not see a reason to. The main floor is on the same schedule, but has never done this three degree burst. I have had three different contractors out, with correponding charges, with no luck. Have you ever seen this? Any thoughts? Thanks! The answer.............

Twinned Split System with a Single Air Handler

7) Richard Very nice site! I have a question; my home was fitted out by the previous owner with a twinned system, and a thermostat (Totaline P374-1900) which was not designed to control discreet, paired units. I confirmed this with Totaline. The result is only one unit runs, and the second unit is never activated. It functions, but not automatically. Your website mentioned dual compressors in one system, and mine is similar, two independent compressor/condensers. Seeing the separate condenser units, I first thought the house was zoned, and later discovered both units feed into one Aspen BHA40 4-roll coil. Besides the issue of the wrong thermostat, I'm having problems finding an HVAC person who understands these hybrid systems and will service it. Is this configuration that uncommon? I live very near Houston Texas, so if you know of a local HVAC person with the skills to help me out - let me know. PS - I checked with Honeywell about the possibility of their thermostats working with my setup. They emailed me - they would only work with a HVAC professional. I thought this was strange since they sell them in the hardware stores. The answer.............