Anyone on here have 1 or know anything about them ive got a question.it was brand new this fall and I asked the hvac guy about and he said its normal.the question is about every 2 and a half minutes it will make a humming noise for about 15 seconds then stop then repeat and its not calling for heat or hot water.i just think its odd that it does this when it isn't needed for either 1.

Is it the low temp setpoint turning the pump on? Refer to the manual.

Ive read the manual and it doesn't say alot in it other then to call them but you have to be a licensed hvac guy or they won't talk to you for liability reasons.

Mine was doing similar (I don’t remember the duration or frequency) and I found a setpoint in the manual that turns the pump on at a certain temperature to prevent freezing. You would have to be running your room temp fairly low for this to be happening. The default temperature was in the low 50’s I believe.

My thermostat in the basement is set at 62 and whenever I happen to be down there its always warmer then that.thanks for the response iam going to get the manual out and read that section.

I got the manual out and doing some research i think the pump comes on to keep the water hot inside the unit so when there's a call for domestic hot water it has some and youll get hot water sooner but if iam reading everything correctly I can shut that off and it will take a little longer to get hot water at the faucets.but iam not positive on this.

My navien boiler does the same thing …. If you figure out what’s causing your boiler to run please let us know ?