Looks like good unit, Long wait!
Waited several months for delivery of 3.5T unit due to shipping issues and COVID lockdowns.
Allen and others at MBTek were patient and as helpful as they could be with something outside their control.
3/4 of my energy bill is for heating between Oct and April. Hoping for a slight overall reduction - it'll depend on future gas prices.
Unit arrived mid April when my radiant floor system goes dormant until Oct. Lots of time for installation!
Now it's installed and running.
Pipe installation was very simple, only complicated by the positioning of the buffer tank. Turned it on and it ran with just the defaults set. It's silent - only audible within 3'. Heats the buffer tank (50gl) to temp in under 30mins (previous gas heater took ~40mins).
The instructions for the wiring took a little educated guesswork, but everything worked first time and it responds correctly to the house thermostats and the water temp settings.
Now we're attempting to add a DHW indirect tank as the old gas unit has just sprung a leak. Expecting great things.