Since I purchased my home 3 years ago (new Construction) my master shower (Moen) has a separate control for adjusting the water temp. It doesn't get hot enough even though the sink right next to it reaches 120F. I removed the control lever which exposes the valve but I have tried everything to see if there is an adjustment but cannot figure out how to get the valve to allow more hot water through it. Attached is a picture. Most cartridges have a plastic adjustment piece. This one does not. I am at my wits end. Any help would be appreciated.