Symptom

Possible Cause

Action

Valves are not opening or not fully diverting the water flow.

1.      Load is too large for the transformer

2.     Transformer is burning out

3.     Petroleum or oil in system fluid causing the small EPDM O-ring seals to swell.

1.     Check and add up the power draws or VA ratings of the valves supported by the transformer.  If the combined VA rating of the valves is higher than the VA rating of the transformer, change to a larger transformer or split the system and add a second transformer.  Note: Do not wire two transformers parallel.

2.     Change the transformer if secondary voltage is measured too low (but not due to district low-line voltage supply) due to faulty transformer.

3.     Replace adapter plate with plug seal and 0-ring seals.  Flush to clean the system and replace system fluid.

Burst pipe and/or burst valve due to freeze ups.

1.     Pipes vulnerable to very low outdoor temperatures, e.g. located in outside wall, near an open window, uninsulated etc.

2.     Occupant leaves door or window open to regulate room temperature.

1.     Add pipe insulation or use a valve with internal let-by that helps avoid freeze-ups by permitting a steady trickle of water through the pipes.

2.      Keep doors and windows near pipes shut in winter or add Outdoor Temperature Compensation control to hydronic system to minimize over-heating problems.  

Equipment seizes up.

Equipment sits idle during long periods, e.g., summer.  The valve or the pump cylinder can seize up.

A knock of a hammer may free the pump cylinder.  If that fails, replace the entire unit.  Install a control timer that “exercises” the pumps and valves by regularly turning them on and off during the warm months.  

End switch failures.

Use of lubricating silicone spray may have damaged the end switches.

Replace the valve actuator.  Avoid using lubricating spray on actuators.  

End switch does not make connection.

1.   Insufficient supply of VA or voltage due to a faulty transformer or due to an excessive drop in district line voltage supply.

2.     Too many valves are powered by the same transformer.

3.      Failed switch contacts due to over current.

4.    Valve motor may be burned out or worn out.

5.     Actuator gear or motor gear may be worn out.

6.     Valve is installed backwards with respect to the flow direction.

1.  Change the transformer if it is faulty.

2.     Add or replace transformer.

3.      Ensure that the actual current draw is within the specification of the end switch. Add isolating relay of the end switch. Add isolating relay if current draw is too high.

4.     Replace valve motor.

5.      Replace Actuator.

6.      Reinstall valve Correctly.