Hi,
What is the maximum current-switching of each of the relays in a VMB4RY?
The manual (link) isn’t too clear - page three says “16A/230V max” whereas page 5 speaks of needing an external relay if “… the consumption exceeds 1000W” which is only about 4.5A at 230V.
As stated the 16A/230VAC rating for the on-board relays is for resistive loads, they are down-rated to 8A for inductive loads. That sort of “spread” in the resistive and inductive load ratings indicates they are light duty contacts (of necessity because of the package size) that should be pushed too hard despite the ratings…
For 2.5kW, even a purely resistive load, I would recommend using an external relay unless that duty cycle and life expectancy (of the relay contacts) are both low–I.e. stick to the “page 5” recommendations, the maximum ratings for those tiny on-board relays should have a 50% service factor applied for anything other than light use.