Gf200 dhw temp off

Deepfish

Hi, we just put one of these in our new home, just fired up a day or two before move in. Heating home no problem. Dhw though is very weak, one has to have shower or faucet open full hot to get a hot ish water supply. Just had a marginally warm shower on full hot. Temp on unit says 140 but at faucet much less. Plumber had a mixi ng valve on outside unit and temp was tested before valve at 138 and after valve was 119 even with valve at full open. They removed valve but temp result is as stated here. It seems like it needs to be turned up or there is something cooling the water or mixing cold in before it gets delivered. Any comments welcome, I'm the home owner not the mechanical or plumber.

nicholas bonham-carter

What make is that, and what shower valve do you have?—NBC

DZoro

Can you post a picture of the installation?