I have a multizone hydronic heating system that has a pump for each zone.
The Pumps are Taco 0015 three speed pumps like this one that I am to understand are permanent split capacitor motors.
The thermostat I am testing is an Aube TH401 like this one that uses a triac for switching.
(I have been using old style bi-metallic thermostats to hold the temperature in each zone but they are very inaccurate and allow large temperature swings.)
So, the new Aube TH401 is a little more expensive but it holds temperature better. It operates on 5 minute cycles on "Fan" mode for a baseboard heater with an integral fan, and 15 second cycles when it is set for straight resistive heat. I have it set on the "Fan" mode since the resistive mode cycles are too short to actually move any water in the zone.
The thermostat has one to four little heat waves on the display to indicate "heat intensity". That is what the manual says. I am assuming it actually controls the amount of electricity a baseboard heater would receive by controlling the duty cycle of the triac.
And now my question: If the duty cycle on the triac is being controlled to hold a tight temperature instead of just turning it full on and full off, can operating a PSC motor on a thermostat like this damage the motor?
EDIT: In the last half of this video the gentlemen shows what he believes is a Triac based fan speed controller. If ceiling fans use PSC motors and Triac speed controllers then it would seem that a Triac based thermostat and PSC pump would be able to work together. I have set the three speed selector to the highest setting so the minimum speed from the thermostat is less likely to be below the pumps starting torque/speed. So far, no black smoke from the motor so the experiment continues.