The Attic Heat Harvester Ltd. powerful microprocessor based Differential Temperature Controller is designed for applications
that compare two thermistor derived temperatures to control external devices based on user pre-settable parameters and a
predefined algorithm. The Differential Temperature Controller also calculates, displays and remembers system performance data.
In the Attic Heat Harvester guise the Differential Temperature Controller continually monitors an attic and a room sensor to determine whether a fan should be turned on to move solar heated attic air from the attic to one or more rooms.
Hardware
System input power: 230vac 50Hz (default) or 115vac 60Hz. - voltage selection made using links.
Micro Processor: Microchip PIC16F1936
Clock rate 2 Mhz
Controller power consumption excluding relay output power - 1 Watt
Thermister: Inputs: |
1 - Attic thermistor 2 - Room thermistor |
30K at 25C 30K at 25C |
Outputs: Display: Keypad: |
1 - 3 amp 230vac SPNO relay - provides 230vac (115vac) to power fan 2 - 0.05 amp max, 18-26vac SPCO relay - provides 24vac to open/close main air valve Option: 3 - 1 amp 230vac SPNO relay - provides 230vac (115vac) to power attic cooling fan 2 line x 8 character 5.6 mm high LCD display with LED backlight 3 push buttons: 'MODE', '+', '-', |
|
Indicators: |
1 - +5vdc on - 2 - System running - 3 - Fan On - |
Green LED Yellow LED - flashes each second in normal operation flashes differently if system errors detected - see error codes Red LED |
Enclosure: |
110 x 110 x 68mm (4.35 x 4.35 x 2.7 in) with clear polycarbonate lid Fixing holes: 4 in a rectangle spaced at 95mm (3.75 in) Weight 0.5kg (1.1lbs) |
Temperatures Current Power (cPwr) Current Efficiency (cEff) Total Power (tPwr) Total Efficiency (tEff) Fan Hours (FHr) Average Temperature Difference (AvTD) |
-9.9 to 70°C in 0.1°C increments 18 to 160°F in 0.2°F increments 0 to 65.5kW in 0.1kW increments 0 to 99.9 in 0.1 increments 100 to 999 in increments of 1 0 to 999.9 kWhrs in 0.1 kWhr increments 1000 to 16609 kWhrs in increments of 1 0 to 999.9 in 0.1 increments 0 to 999.9 in 0.1 hr increments 1000 to 6553 (270 days) in 1 hr increments 0 to 25.5°C or 0 to 45°F |
Range | Default | |
Attic Temp - Room Temp (AtT-RmT) Max Room Temp (MaxRoomT) Fan Flow (Fan-Flow) Fan Power (FanPower) Max Attic Temp (MaxAticT) |
0 to 25.4°C 0 to 42°F 5 to 30°C 41 to 86°F 0 to 5120 cmh 0 to 3060 cfm 0 to 255 watts 35 to 60.7°C 95 to 141°F |
3°C 5.4°F 23°C 73.4°F 1400 cmh 820 cfm 90 watts 50°C 122°F |