DIY or you're crazy - Hydronic heating tapped off indirect WH stopped on all three zones

KamboPC

We have no hydronic heat circulation to all 3 levels of our townhome and I believe it’s both the cartridge circulator and a motorized actuator valve that are seized.

System design is this.

• Boilers in common area serve 8 units
  
• Hot water from boilers feed an indirect water heater – this is working fine we still have hot water flowing to our house.
  
• Auxiliary pipe out of indirect heater feeds the 3 zone hydronic system. 3 zone is a brass manifold
  
• One cartridge circulator for 3 zones with actuators on each zone plus for whatever reason a common motorized valve actuator in another area.
  
  

Triage so far

• Confirmed control panel is lighting green for each zone
  
• When demand from thermostat additional red light comes on down below for that zone
  
• Confirmed power to cartridge circulator
  
• Confirmed 24v power to motorized valve actuator
  
  

My hypothesis

• Root cause: I noticed black sludge dripping from the manifold. Looks like that probably seized everything.
  
• Cartridge circulator is seized up due to sludge – see brand/parts below
  
• A Honeywell motorized valve actuator under the circulator is shot, spring return, etc.
  
• Probably worth swapping out the actuators on the 3 zones – showing the new replacement for the Wirsbo actuator and space rings for brass manifold.
  
  

hot_rod

Does the circ get hot, scalding hot. That can be an indication of a seized pump.

Most often you have an air lock, or the pump is not spinning. Could be a control issue if there is no voltage on the circulator.

KamboPC

Welp found out it's the control board having only 16V from the control board on some of the zones.
So replacing the main Taco control board and the Honeywell MVA -and it's all good.