Lochinvar Noble Combi 199--- very little hot water

Brand new installation of Lochinvar Noble Combi, propane, even though the temp DHW is set above average temp, we are getting very little hot water before it runs cold, 10-12 seconds worth. Before installing the recirc loop with aquastat the volume of hot was plentiful. Of course that was before the space heat season triggered that demand on the unit too. Advice? Yes, if we turn off the tap for a minute or two it will warm up then be hot for another 10 seconds.