What type of water heater are you using: Tankless or Tank?
If tankless, these are NOTORIOUS for giving poor hot water flow (see the NUMEROUS threads on this site about that).
If tank, are you POSITIVE you're not bypassing the water heater? In our old 365BHS (tank style), it was VERY EASY to bypass the water heater (simple valve positions on the control panel) for winterization. If you're bypassing, MAKE SURE YOU DON'T RUN THE WATER HEATER. You'll overheat the system without water in the tank - VERY important.
Highlands Ranch, CO
2015 Seneca 37TS ("Screaming Eagle")
2009 Hummer H3 ("Ranger")
2005 Chevy 2500HD ("Max")
2008 MasterCraft X-15 ("One More Time")