If you happen to have a circulator pump that cannot stop running, then there are a few different things that you can do to help this. It can end up being costly if your circulator pump is running all of the time. It could also result in corrosion as well as your pump just not lasting as long as it should. Being able to stop the constant running as soon as possible is something that you are going to need to do so that you can keep your circulator pump in good shape for a long time to come.
Step 1 - Weld Relay Contacts
Whenever this happens, it is usually because your relay contacts will need to be welded. Welding is something that you should not do unless you have experience in it. It is always a good idea for you to hire a professional to do the welding for you unless you have experience in welding and feel confident in being able to do it yourself.
Step 2 - Further Inspection
If you find yourself wanting to check your system out further, then you can do this by getting the power to your system cut off. You then need to remove your wires temporarily from the TV as well as the T. You will be able to find these wires at your zone valves. Whenever you remove the wires and get your system turned back on check to see if your circulator stops. If it does, then it turns out that the problem all along was with your zone valves and the wiring. It may have even been your thermostat that could have been the issue. The thermostat is the least likely candidate should this happen, it should still be noted though.
Step 3 - Measure with Multimeter
You should only do this if you know how to use the OHMS function that is on your multimeter. The multimeter will measure the voltage and current of the wires. If you do not happen to have any type of thermostat that is in need of heat, then you will need to look for there to be an open circuit along with infinite ohms. Whenever your thermostat does call for heat, then when your zone valves do open up, then there should be the same short circuit as well as zero ohms.
Step 4 - Trace Your Wires
You will need to make sure that you take the time to trace your wires from your circulator all the way back to the aquastate. This will need to be done so that you can be sure that your circulator is not being powered directly by anything else. You should know that there are some systems that will power your pump directly. It is these pumps that are going to run nonstop only because of the way that they were made. There is nothing that you will be able to do to fix these as this is the way that they were built to run.