Most likely, yes because you are not evaporating out the proper amount of water to condense the wort over the same amount of time. You really want a nice boil to concentrate the wort
There are also mash efficiencies to take into account as well but first you need to get a proper boil and see how it turns out and go from there
Nothing Left to do but smile and drink beer.....
The Commune Brewing Company-Perfecting the "art" of beer since 2010