Is this the correct wiring?

jamespet

I have a taco sr501-4 running a hydronic heating system in a garage I just bought. It didn't work when I moved in. Though I was told it did. The system was dry and I had to fill it. A fuse was blown, so I replaced it and turned on the system. The fuse blew again. I disconnected (removed power) the pump that initiates the tankless heater(no boiler) and turned the system back on. The circulator did not move, but it did get hot. turned it off. Cartridge from the circulator was seized (taco 007-f5). I then disconnected the circulator(from power) and reconnected the pump on the tankless(taco 0013-sf3). Turned the system back on the the fuse blew again. Turned the system off and pulled the pump. The impeller had busted off and I could see scorch marks in the motor after removing the cartridge. The cartridge was very difficult to remove.

Note: replacing the cartridge from the 007 and the motor assembly from the 0013.

My main question is this. The wiring of the system does not match the diagram for the wiring for this system. I just want to be sure that it is wired correctly or if I need to move the pump wiring over to the boiler connection.

STEVEusaPA

What was the quality of the water?
You have 2 circulators on that terminal?
Are you saying when t-t closes, it's from the aquastat, and the boiler pump and the pump for the indirect zone need to run?

EdTheHeaterMan

If you remove both wires from #4 N/O and turn on the thermostat to the relay, Does the fuse blow?
Answer should be NO
You mentioned the Taco 0013 has what looks like burnt wires in the housing that holds the cartridge. Those burnt wires are shorted and will cause a fuse to blow every tine, You will need a complete new circulator.

mattmia2

So you have a boiler pump (circulating through a misapplied tankless water heater) and a system pump?

Kind of sounds like someone fried the circulators by running them dry.

EdTheHeaterMan

There is some question about your terminology. What is the brand and model number of the "Tankless" device that the "Tankless Pump" is connected to? Or a picture of the device would help.

There is no reason to have both those pumps operate unless someone designed a heating system using the wrong appliance. If However some genius decided to use a tankless appliance designed for DHW to be used for Space heating, then that is part of the reason you are having problems.

Bottom line is one or both of these circulator pumps has a dead short. Try plugging the pump directly into a breaker protected electrical outlet. You can wire nut the pump leads to a lamp cord. If the pump is good the rotor will spin when plugged in. If the pump is shorted the breaker will trip.

You will need to replace any pump that causes the breaker to trip.