Ever had a zone pulse or bounce occasionally?

Timco

Back zone of my house. A couple times a month I hear an engine idling in the distance. It’s my back zone pulsing or bouncing. Good x tank, 15-58 med speed. Changing anything quickly stops the phenomenon.

Thoughts? It’s strapped tight.

Solid_Fuel_Man

15-58 got an IFC? Is there also a flow check in the circuit? What is your deltaT with it on low speed?

hot_rod

TRV on the circuit? sometimes they will pulse. Agree with the integral check valve in the circulator, it could be causing some pulsation on low flows.

Timco

Actually there is a FC in it and I put a spring check on returns to keep zones flow separated. Remove return spring check?

hot_rod

The spring checks, were they hydronic type? Checks can have different "pop"or cracking pressure. Here is a common Conbraco soft seat check used for hydronics, notice the different pop pressures available.

I think those checks in the circulator are somewhere between .35 and .50 psi crack. if you get too stiff of a spring the valve may hunt around causing the surge.

Ideally when sizing a check use the flow rate not pipe size, often the check can be a few sizes smaller then the piping.

Also know the Cv is with the check full open. If you have too much spring the check will possible rattle and also add some pressure drop, maybe turbulance if it in a partially open positions .