Thermostat Question

[omega50]

Hungarian MIL moved to new condo with Electric Baseboard Heat for winter and a Air conditioner compressor for summer on her balcony plumbed back to her laundry room with an evaporator pan and vented to each room just below the ceiling.

Have set the centrally located Wall Thermostat asking for 20C, but getting really frosty at about 15C actual. Reset the wall setting for 25C and still getting about 18c actual. What is at play here?

Generally speaking how do I close the gap between desired and actual on the Cool Setting. Is there usually a quick way to achieve this?

[dewalt18]

Make sure you're setting the right thermostat. There will likely be two, one for the ducted ac, and one for the hydronic heating, although there is a possibility of them both being controlled from one. If it's freezing up like that, the two most likely causes are lack of airflow (either a clogged filter, or a non functioning fan) or the ac system is undercharged, causing excessive evaporation at the indoor coil

[Weedy1]

Originally Posted by omega50

Hungarian MIL moved to new condo with Electric Baseboard Heat for winter and a Air conditioner compressor for summer on her balcony plumbed back to her laundry room with an evaporator pan and vented to each room just below the ceiling.

Have set the centrally located Wall Thermostat asking for 20C, but getting really frosty at about 15C actual. Reset the wall setting for 25C and still getting about 18c actual. What is at play here?

Generally speaking how do I close the gap between desired and actual on the Cool Setting. Is there usually a quick way to achieve this?

If you can take a picture of the thermostat(s) we could give you a better idea of what may be going on.
My guess is she has a single stage heat/cool thermostat or two thermostats as Dewalt pointed out.
The thermostat sounds like it is out of calibration, possibly damaged or even mounted incorrectly.
If it is an older thermostat that uses mercury switches it must be level in order to function correctly.
If it is an electronic thermostat, programming of the thermostat may be an issue.
If it is a pneumatic thermostat there could various reasons that it is over cooling depending on the control sequence.
Also, is there any heat source directly under the thermostat such as a computer monitor or is the thermostat perhaps being hit by the sun?
Many possibilities, need more info.

[omega50]

Originally Posted by Weedy1

If you can take a picture of the thermostat(s) we could give you a better idea of what may be going on.
My guess is she has a single stage heat/cool thermostat or two thermostats as Dewalt pointed out.
The thermostat sounds like it is out of calibration, possibly damaged or even mounted incorrectly.
If it is an older thermostat that uses mercury switches it must be level in order to function correctly.
If it is an electronic thermostat, programming of the thermostat may be an issue.
If it is a pneumatic thermostat there could various reasons that it is over cooling depending on the control sequence.
Also, is there any heat source directly under the thermostat such as a computer monitor or is the thermostat perhaps being hit by the sun?
Many possibilities, need more info.

Definitely single stage Thermostat- Top Left-Fan swith-Auto or On
Top Right-Cool-Off-Heat. Right side sliding lever for Temp Set.

Currently fan set to On and mode to Cool.
Pulled down ceiling tiles in Laundry Room and filter is spotless as new.

Will take pic of Thermostat face and interior next time I am in her area.

Talked to some other people in the building and common problems is for evaporator pan to overflow and drop over a litre of water into laundry room- Which it did a few weeks back when she was in the hospital and mode was set to Off as she was hospitalized for a few weeks. Once she had this leak- I set to Fan to On and mode to Cool to continue flow over evaporator-Perhaps I contributed to this issue?

[Weedy1]

Originally Posted by omega50

Definitely single stage Thermostat- Top Left-Fan swith-Auto or On
Top Right-Cool-Off-Heat. Right side sliding lever for Temp Set.

Currently fan set to On and mode to Cool.
Pulled down ceiling tiles in Laundry Room and filter is spotless as new.

Will take pic of Thermostat face and interior next time I am in her area.

Talked to some other people in the building and common problems is for evaporator pan to overflow and drop over a litre of water into laundry room- Which it did a few weeks back when she was in the hospital and mode was set to Off as she was hospitalized for a few weeks. Once she had this leak- I set to Fan to On and mode to Cool to continue flow over evaporator-Perhaps I contributed to this issue?

From what you are describing she has a fan coil unit in the ceiling of the laundry with a split DX cooling system, + radiant heating. I would guess the thermostat is pooched. How old is the place/thermostat?

Does it look like this?



If you had the mode/system switch set to OFF it should not have run the cooling at all thus there should not have been any condensate except maybe residual.

The evaporator pan catches the condensate. Is there a trap on the condensate drain line and if so how high is it? Whether the fan blows or draws through the coil the trap height is very important in order to prevent problems. See here: http://www.azashi.com/a/Attitude_and_Altitude Keeping the drain line clean is important too.

[omega50]

Originally Posted by Weedy1

From what you are describing she has a fan coil unit in the ceiling of the laundry with a split DX cooling system, + radiant heating. I would guess the thermostat is pooched. How old is the place/thermostat?

Does it look like this?



If you had the mode/system switch set to OFF it should not have run the cooling at all thus there should not have been any condensate except maybe residual.

The evaporator pan catches the condensate. Is there a trap on the condensate drain line and if so how high is it? Whether the fan blows or draws through the coil the trap height is very important in order to prevent problems. See here: http://www.azashi.com/a/Attitude_and_Altitude Keeping the drain line clean is important too.

Yup-Very similar looking Thermostat.
Unit was built in 1999

Will poke around to look for a drain line, but nothing obvious under the tile that collapsed except the pan itself. Perhaps I need to pull a few more ceiling tiles.

System was off for a least 2 weeks before the pan overflowed and found a leak path out through some screw holes and took down the ceiling tile below. Initially thought it was a washer overflow from the unit above, but a call to their property management hotline assure me it was the air conditioning and a very common issue in the building. So I took their word for it.

Made no sense, but it happened so I forced the fan on the help evaporate any residual water