Whilst I am not exactly an Ultimaker owner, I have incorporated various Ultimaker parts in to my UM2 reprap clone.
All the electronics are working well (hotend, motors etc.) however, I have run into a problem with the OEM UM2 heat bed. I have the heat bed connected through a SSR relay to a 24v 300w PSU triggered by a Printrboard control board. Unfortunately, the heat bed takes around 15 minutes to heat up to around 80 degree Celsius and then levels off. This is not to the controller managing the heat but simply because the heat bed will not heat up any further. I have even directly connected the heat bed to the 24v 300w PSU without the controller and relay and the same thing happens.
I thought it might be a faulty UM2 heat bed so I bought a new one. No luck there.
Any ideas what may be causing this issue?