Roof exhaust fan with too much exhaust

[John]

My roof exhaust is too powerful. When the electrician set it up he asked whether I want it to full power or half. It was set to full power.

The exhaust fan takes two 230V lines. What if one 230V line is disconnected will it be half power or will I damage to fan? I am sure to get a fully qualified answer one would have to inspect the connections and such but generally speaking would disconnection the other 230V line be the usual solution? I am thinking of just shutting the breakers to the other line.

[RBM]

It doesn't work that way. It is probably a 230 volt motor and has two speeds, which are internally changed. Have him or an electrician come and reconnect it for the lower speed

[Mikepier]

Also ask if possible if he can wire up the 2 speeds to a switch you can control downstairs. So on really hot days you can turn it up to full speed and other days you can have it on low speed.

[John]

I scrambled up and looked its specification plate. It says "Y/A 380/220 V" What does that mean? The motor is at least 30 years old if not older.

[CJT]

If it's thermostatically controlled, how can it exhaust "too much?"

Just adjust the thermostat.

If there's no thermostat, get one installed.