is a taco circulator supposed to block the flow when not running? (HVAC question)?

Question

I have a 5 zone heating system and I've noticed one of our zones gets hot even when the circulator is not runnng. I've verified there is now power running to the circulator for this zone. I've also noticed that the pipe on the inbound side of the circulator is hot....

Answer 1

it probably isnt the circulator, if you have more than one zone valve then check and see which one is calling for heat and you will probably find that the zone valve is not working properly. very common. if no zone valves then check t-stat for each zone and see which one is calling, disconnect t-stat wire and if circulator stops then its either the t-stat, or a broken wire or staple in wire making it stay on.also common problems. sometimes there is a flow control installed and goes bad, if this is it then could be gravity feeding. hope this helps,

Answer 2

The pipe on the input side of the circulator is often hot as heated water rises from the furnace. The circulating pump will allow water to flow through in either direction if it is off. It sounds like you have a zone valve problem. If it is faulty or stuck open water will flow through the valve and into the heating zone, even if the thermostat is not calling for heat.

I recently found a similar problem in one of my five zones, but fortunately had a spare zone valve installed a short time ago. I relocated the output line and rearranged the control wiring. When time comes that I need the sixth zone valve I'll have to replace the faulty parts.

Answer 3

The circulator does not block the flow when it is off, that's why you have valves in the system. The zone that still gets hot must not be sealing off.

Answer 4

you may have a bad zone valve. The zone valve is what opens and closes allowing hot water from the boiler to be pumped through that zone