Relays for switching circuilation pumps
I would say those relays are inappropriate for a heavy motor load. Relays intended for a motor load will be much larger and more expensive. Motors have inductance that causes arcing during switching (particularly switching off) and draw a large surge current.
When &quot;on&quot; and up to speed the load is not that different from a resistive load, but that does not really help except that the relay contacts will not overheat if rated for appropriate RMS current.
Here is an example of a relay series that is rated for, and recommended for, motor loads. Of course you still should evaluate the lifetime and other specifications in relation to all your requirements.