3d press dropping temperature then taking ages to get back up.

[Kyebie]

Hi
I have a 3d vacuum heat press from coralgraph. when in use the temperature can drop from 195C to 168C then it hoovers at that temperature for a while before a slow gradual rise back up to the set temperature. Should this happen when in use.... its bugging me.
any help would be great.
Thank you all.

[Ucase Ltd]

Is this the ST3042?

If so it may be the temp sensor needs replacing. Not sure if there are any uk stockists for these.