The 40 amp relay is used in conjunction with a 3iE series thermostat in order to expand the original 15 amp capacity. It is specifically designed for large applications beyond 300 sqft.

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Miscellaneous questions Picture

How can I keep my relay from being loud/buzzing?

All relays ‘buzz’. A good example is the transformers for low voltage lighting in the house. When the room is quiet, you can hear the humming of the transformer or relay. Click “Read More” for details.