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WCohn
WCohn, Construction Worker
Category: HVAC
Satisfied Customers: 764
Experience:  Been in contruction 18+years
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I believe that one of my zone circulator pumps(grundfos) is

Customer Question

I believe that one of my zone circulator pumps(grundfos) is bad. The zone is circulating, even when the thermostat is off, and the power is off to that pump. Is it possible that when another circulator on the boiler is activated, that water is circulating through the zone of the bad pump? All of my zones are obviously hooked up in parallel with the boiler. Thanks.
Submitted: 2 months ago.
Category: HVAC
Expert:  WCohn replied 2 months ago.

Hello, my name is ***** ***** I look forward to helping you!

Expert:  WCohn replied 2 months ago.

Do you have zone valves.

Customer: replied 2 months ago.
Expert:  WCohn replied 2 months ago.

Does each zone have a pump and solenoid valve?

Customer: replied 2 months ago.
Three tacos and a grundfos. The grundfos is the problem.
Expert:  WCohn replied 2 months ago.

Can I see a picture of the manifolds from a distant and also the pump controller?

Customer: replied 2 months ago.
Did that work?
Expert:  WCohn replied 2 months ago.

Just got them please wait a sec while I review

Customer: replied 2 months ago.
I removed the widget from the controller to that zone to see if it solved the problem. That's why the cover is off.
Customer: replied 2 months ago.
I don't know the correct term for the widget.
Customer: replied 2 months ago.
This is the questionable pump.
Expert:  WCohn replied 2 months ago.

The pump is NOT the issue, the controller is not recognizing the thermostats signal. Or the thermostat is bad

Customer: replied 2 months ago.
If the electricity is off to the pump, how is the water traveling through the pump? I guess the thing I don't understand is does the solenoid in the pump turn it on and off, or just open and close the flow?
Customer: replied 2 months ago.
I have two other thermostats on the other zones that are working. I'll switch one of them and see if it works. If not, I'll switch one of the widgets from one zone to the next to see if that works. Can't do the phone call tonight. Maybe tomorrow.
Expert:  WCohn replied 2 months ago.

Wait.

Customer: replied 2 months ago.
OK. Thanks.
Expert:  WCohn replied 2 months ago.

Can you feel the pump running? or just water flowing through it?

Customer: replied 2 months ago.
Im pretty sure just water running through it. The sound is transmitted from the other pumps, so its hard to tell, but I believe the sound is just the water, because it didn't sound any different after I cut the power to the circulator in question.
Expert:  WCohn replied 2 months ago.

Water running through a pump is totally normal. unless you have a zone valve closed

Customer: replied 2 months ago.
Why would the water be running through the circulator when the thermostat isn't calling for heat?
Customer: replied 2 months ago.
I thought the thermostat calls for heat, and the controller turns the pump on??
Expert:  WCohn replied 2 months ago.

I can explain this better over the phone. If that doesn't work for you please wait while I type up my explanation

Customer: replied 2 months ago.
Meaning the pump doesn't activate until the thermostat calls for heat??
Customer: replied 2 months ago.
Sorry.
Expert:  WCohn replied 2 months ago.

It's okay =)

Customer: replied 2 months ago.
I'll wait.
Expert:  WCohn replied 2 months ago.

Each one of these thermostat wires control a zone pump (wait there is more)

Expert:  WCohn replied 2 months ago.

These are your secondary loop zone pumps that are controlled by the stats ( still more)

Expert:  WCohn replied 2 months ago.

Secondary loop pumps

Expert:  WCohn replied 2 months ago.

This is your PRIMARY pump, it is controlled by a temp controller and should always be maintaining heat when in heat mode, If it's pumping and a zone valve is open then it with push water through another secondary pump until the zone valve is closed

Expert:  WCohn replied 2 months ago.

The thermostats control the secondary pumps, but water can still flow through them if zone valves are open

Expert:  WCohn replied 2 months ago.

Does that make sense or do you have questions?

Customer: replied 2 months ago.
Thanks. Didn't know that. What closes the zone valves? Is it something electronic?
Expert:  WCohn replied 2 months ago.

Modern systems are. They turn on seconds before the pump. I didn't see electronically controlled valves in your pictures though

Expert:  WCohn replied 2 months ago.

This may help

Customer: replied 2 months ago.
That might sound stupid...aren't the taco pumps electronically controlled?
Expert:  WCohn replied 2 months ago.

Yes, but they don't prevent water from flowing through them when off.

Customer: replied 2 months ago.
if water is always flowing through them, what determines the temperature of the water? I mean how can the water flowing through one be cold, and the one next to it be hot?
Customer: replied 2 months ago.
Gotta call it a night. Thanks for your help. Will continue tomorrow if I can.
Expert:  WCohn replied 2 months ago.

Sure, but I'm a plumber by day so my availability is usually evenings.

Water runs the path of least resistance so I bet water is NOT going through the whole loop