[Palmyweather]

Thank you for the additional suggestions

Measuring the voltage across the data pin to ground gives 4.4VDC reading.

I have enabled the serial data output from the DHTxx library with the below results. I note that the serial data from the DHTxx library only displays once on the initial reading and not again.
 

Code:

DHT 14 3 4 4 4 4 3 12 4 4 12 4 12 4 12 4 4 4 3 4 3 4 4 4 4 12 12 12 3 4 4 12 4 4 4 12 12 12 3 4 4
HEX 15 2 54 0 E2 38 : 38
Sending ID0...
  Sensor 0 - Temp: 0.00  Hum: 0.00
  Sensor 1 - Temp: 22.60  Hum: 59.60

Sending ID0...
  Sensor 0 - Temp: 0.00  Hum: 0.00
  Sensor 1 - Temp: 226.00  Hum: 0.00

Sending ID0...
  Sensor 0 - Temp: 0.00  Hum: 0.00
  Sensor 1 - Temp: 293.92  Hum: 0.00

Sending ID0...
  Sensor 0 - Temp: 0.00  Hum: 0.00
  Sensor 1 - Temp: 317.76  Hum: 0.00

Sending ID0...
  Sensor 0 - Temp: 0.00  Hum: 0.00
  Sensor 1 - Temp: -99.20  Hum: 0.00

After board reset:

Code:

DHT 14 4 4 4 3 4 3 12 3 4 11 12 3 4 12 4 4 4 3 4 4 4 4 3 4 11 12 12 4 3 4 11 12 4 12 4 4 12 4 3 12
HEX 15 2 64 0 E3 49 : 49
Sending ID0...
  Sensor 0 - Temp: 0.00  Hum: 0.00
  Sensor 1 - Temp: 22.70  Hum: 61.20

Sending ID0...
  Sensor 0 - Temp: 0.00  Hum: 0.00
  Sensor 1 - Temp: 227.00  Hum: 0.00

Sending ID0...
  Sensor 0 - Temp: 0.00  Hum: 0.00
  Sensor 1 - Temp: 303.92  Hum: 0.00

Sending ID0...
  Sensor 0 - Temp: 0.00  Hum: 0.00
  Sensor 1 - Temp: -237.60  Hum: 0.00

Sending ID0...
  Sensor 0 - Temp: 0.00  Hum: 0.00
  Sensor 1 - Temp: 245.44  Hum: 0.00

So it looks like additional requests for data of the DHT sensor is not occurring.

As an idea, would you mind zipping up your working code with the DHT sensor you tested last week and supplying it with the library etc to see if I can get your code to work correctly on mine?

I have ordered new DHT22 sensors from China, due end of the month. It will be interesting to see what results I get then if we cannot find a solution before that point.

Thank you once again for your help.