thermostat not starting the circulating pump

Frank_62

Kirk it sounds from your limited discription you have a hot water boiler two zones that i'm guessing are zone valves. If you can lift the therostat/pump contact in the relay before the burner and bring in the burner and pump you probably have a bad 24v transformer. one side of the transformer would be connected to the zone valves and one side to the relay. Do you get your domestic hot water off the boiler? you mention a 120 degree setting,if their are three dials on the relay and the low limit is set to 120 and you were getting hot water before that's ok as for your install of expansion tank and pressure reducing valve(?) hopefully you purged it out and your pressure gauge reads 12-15lbs don't fire the boiler without water in it.follow the wires back and you'll see the transformer probably mounted in the 4x4 box you mentioned with two 18 ga wires attached, the back side is line voltage (120) be carefull. check to see if you have line voltage to the back of the transfrmer and 24 volts on the front if this is not the problem repost and give as much info as you can good luck

Kirk Bentley_2

thermostat not starting the circulating pump

Hello, I have a hot water heating system with a "SuperHot" boiler. Neither of my two thermostats will start the water circulating pump. The pump is okay because I can switch it on manually. I don't think it's a thermostat because both from different zones fail to actuate the pump.
Could it be the relay? Is the relay inside the 4" square box and do you have to buy it all as one unit?

Need help! thanks......Kirk Bentley

JK_3

more information

some relays have an adjustable min starting temp for the circ to turn on ,is this the case and if so what is the set point. Is this a newly developed issue or were there recent changes made. do you have a volt meter and are you familiar with electrical circuts?

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Kirk Bentley_2

The minimum set point was about 120, but now the boiler get completely cold. This is this a newly developed issue, the only recent changes were I installed a new pressure reducing valve and a new expansion tank. I do you have a volt meter and am somewhat familiar with electrical circuts.

Could it be the relay because I can force the relay magnet with my finger to connect and it will start the pump and boiler.

Kirk Bentley_2

Thank-you very much, Frank. I'll try your suggestion and test the transformer. Either way, I'll post back with the results.

Thanks again....