I also had to send my Chargemaster 1500 back for replacement due to the number pad not working correctly.
I would press 4 and get the decimal.
I would press 5 and get a zero.
Sent it back and they replaced it with a new one. Was torqued that I had to spend $35.00 for shipping it to them for what I thought (knew) was a design flaw but at least they replaced it FOC.
New one works fine.