Do not see historical trend when using prometheus as data source

I am new to running Grafana and prometheus and have configured prometheus to receive temperature data from a sensor. The sensors send the data to telegraf every 10 minutes for prometheus to scrape on a server that it is already pulling data for.

I have two panels on a dashboard, 1 is a gauge to show last (no null) value and the other is a graph to graph the temperature over time. Below is the query for the gauge which appears to show the temperature correctly.

query = RoomTemps_value{host=“FrontPortchTemp”,instance=“”,job=“ctrlr”}

The problem is with the chart, when I first set this up, I was able to get a graph for the last 12 hours, but if going to a shorter interval no data was shown. It has now been two days thinking I should be able to go back for the last 12 hours or 24 hours and I now get no data for any interval I select for the chart.
Below is the query for the chart

Below is the picture for 1hour

If I go into prometheus I do not see any data for the last 6 hours but if I look at last 2 hours or shorter I do see data. Also why will prometheus not show any data beyond 2hours, the first day I was able to get 6 hours, now I do not even get that.
I would thought the chart would show something all the way up to 2hours (i.e last 2 hours, 1hour, 30 min, etc)