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mikenri 12-19-2011 06:19 AM

Circulator pump runs constantly
I have a hydronic heating system w/ three zone valves.
Recently the circulator pump (taco) has been running constantly even though no zones are calling for heat.

It does not seem that a zone valve is stuck, the various parts of the house heat and cool normally and it's not like the heat is constantly running in a zone.

I tried moving the manual zone valve levers figuring maybe it was stuck a little bit but that didn't help.

It seems that the zone wiring all goes in to a honeywell controller board on the boiler.

Any ideas before needing to get a service call?

thank you.

biggles 12-19-2011 07:33 AM

if you have 4 low voltage wires out of each zone valve....then there is an end switch that closes to call the circ in for the active zone as the others call the same action.with the first running the others do the same but the circ is already as the stats satisfy the zone/CLOSES the end switch/OPENS the circulator call to run... :wink:circ is still running with the follow up zones still heating.until the last zone satisfies the circ runs.:huh:moving the manual bar only opens the valve causing the end switch to make to circualtor....:thumbsup: ...trick with the zone valves is if it has resistance when pushing it(bar) the zone isn't calling..if it just swings over easy the zone is calling circ running stat calling.all 3 zones go to the module on the boiler shut all 3 zones off on heating even removing stat off subbases...module should drop out..verify the zone valve has resistance on that bar(closed position indicated)if it is still running disconnect only one at a time the end switch wire per zone(just break one end switch wire needed.this is isolating the closure points and working you towards the module relay sticking for the stats are off the wire per end switch each disconnected...and the circ is still running:mad: relay module is sticking tap the relay module enclosure or read R to W there if you can...shouldn't be 24Vs might be a slight feed back voltage but not that.....lets hear back just giving out a techs break down run thru..why pay them it's Christmas time:thumbup:

mikenri 12-20-2011 06:36 AM

Seems i have a problematic zone valve afterall.

i noticed one of the zones wasn't getting heat last night so i went to bleed out air bubbles this am after letting the system cool and the head for the zone valve fell off when i went to manually open it.

i had a repair guy that worked on that zone valve last winter that wound up replacing the zone valve head after the valve wasn't opening properly.

it must have not been put on completely right, after reconnecting the zone valve head the circulator pump wasn't running all the time anymore.
i made that zone call for heat, things were working ok.
shut the zone off, i heard the valve close but the pump is still running again.
the valve does closed though as things were cold with the head off overnight so i can hear the fins on baseboards expanding when i turn the zone off then on again.

i have three wires going in to each zone valve.
i'm going to try to disconnect one of the wires from the problematic one now.

thanks for your help!

mikenri 12-20-2011 07:23 AM

Ok, so i do have 4 wires, there are 3 connections on each zone valve.

i disconnected a wire from zone valve 1 (the one that was acting up) , and the pump was off after turning the power back on, i left that wire disconnected.

i made zone 2 call for heat, pump came on.
turned it off, waited a few minutes and the pump stayed running.
disconnected the thermostat on the wall for zone 2, after a couple of minutes the pump shut off.

i'm trying it again and will wait longer after shutting off the zone to see if the pump shuts off.

if not, do you think this is a problematic relay or stat?

i misplaced my multimeter so i cant do a voltage reading right now but i'll locate or pick one up today.

Zone 3 is connected to a wall heater in a garage area, the unit has never worked since i bought the house.
so i dont know if i'll really be able to test it by disconnecting zone 2 and trying to have 3 call.

mikenri 12-20-2011 07:48 AM

I wasn't waiting long enough, it was ok this time with zone 1 disconnected and turning zone 2 on/off.

the pump did shut off properly this time.

with the history of problems with this zone valve i'm not sure if it's a problem with the head, the valve or an electrical/relay issue.

i'll get a multimeter and a new zone valve head to try.

heat wise it does seem the valve works ok.

i actually have 5 wires going in to each zone valve.

Zone 1:

1 - red
2 - red + white
3 - white + blue

Zone 2:

1 - red
2 - red + red
3 - white + white

Zone 3:

1 - red
2 - white + white
3 - blue + blue

from a voltage or continuity standpoint any ideas on what i should see on the wires?
to be honest i'm new to heating systems and have been learning as i try to fix it.


biggles 12-20-2011 08:08 AM

just do too much too fast one zone at a time keeping in mind the boiler works from the action of A zone valve(either with 1 or 10 zones doesn't know how many there are) which in turn reacts to the stat call....if you pull all the stats off the subbases the circualtor shouldn't run.if a test zone is running and the circ is ON as you saw the circ goes OFF.when the stat calls you should see 24Vs at the zone valve making it swing.. the third wire is the end switch/circulator closure and is either side of the 24Vs being sent to the boiler module and relay for the circ.just like you see the zone valve get 24V to swing the relay/circ is waiting on the zone/end switch to close...if the circulator is running with no call for heat the module needs to be looked you have 24Vs at the module if nothing is calling is the mystery...i think were're away from a stuck relay if its reacting to the stats calling or being removed....keep it going lets hear back

Grampa Bud 12-20-2011 08:58 AM

OOOPS I sent you erroneous garbage. Sorry.

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