Before I pick up a new $85 circulator pump assembly from Home Depot I'd like to be 99% sure that this is the problem my heating system won't cycle on and work. Didn't notice it wasn't working for 1-2 weeks until a cold spell hit again. It also has a tankless water heater so the burner runs every few hours no matter what. It's still doing that fine, just not sending hot water to the heating registers. I'd rather not unbolt the old circulator only to find it doesn't all go back together properly...taking down the hot water system too.
The thermostat works as it triggers the circ pump relay when cycled. And I jumpered it out one time just to be sure. After being "on" for 5-10 minutes the casing of the circulator pump gets extremely hot...approx 140-165 deg. F as I can't leave my hand on it. The surrounding piping is no more than 80-110 deg. The circulator piping feels the same temp. just when the hot water is running to the faucets. I put a screwdriver to the volute of the cast iron pump housing to see what I could "hear." All I got was an electrical "hum" and no sounds of flow noise or cavitation. To seal the deal my wife said she smelled a funny odor at the bottom of the basement stairs a few days ago. We chalked that up at the time to the carpet pad in that area. She smelled that same thing yesterday (burnt insulation?) within minutes of when I was testing the circulator again. I couldn't smell it.
Other choices? Any control/instrumentation issues shouldn't even allow the pump to run. Build up in the pump or a piece of debris that has locked the rotor? That at least seems plausible. System air bound? Discharge piping flow check stuck? Doesn't seem likely as in 26 years with our heating system no air pockets have formed that required venting or affected system operation. No recent maintenance where the system was opened. I checked out a few of the upper register air vents and they push out solid water streams. The Taco air scoop high vent (only 1 yr old) is properly adjusted. This circulator pump does have an internal check valve assembly inside the discharge flange .
Other things to check or is it highly likely the pump motor is fried? I'm due for a furnace cleaning so I can probably time that with the circulator troubleshooting/replacement. Either I can do it the day before....or work with the burner tech.
Taco circ pump (no LED on my older version)
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Misc: circulator is installed on the return side. The pump/motor assembly is mounted in standard/recommended positions as per Taco drawings....the impeller is mounted horizontally. The burner water jacket was replaced on warranty 9 years ago, so I'm not 100% sure if the circulator might have been replaced at that same time. If not, then it's 19 years old along with most of the Burnham furnace/boiler controls.
The thermostat works as it triggers the circ pump relay when cycled. And I jumpered it out one time just to be sure. After being "on" for 5-10 minutes the casing of the circulator pump gets extremely hot...approx 140-165 deg. F as I can't leave my hand on it. The surrounding piping is no more than 80-110 deg. The circulator piping feels the same temp. just when the hot water is running to the faucets. I put a screwdriver to the volute of the cast iron pump housing to see what I could "hear." All I got was an electrical "hum" and no sounds of flow noise or cavitation. To seal the deal my wife said she smelled a funny odor at the bottom of the basement stairs a few days ago. We chalked that up at the time to the carpet pad in that area. She smelled that same thing yesterday (burnt insulation?) within minutes of when I was testing the circulator again. I couldn't smell it.
Other choices? Any control/instrumentation issues shouldn't even allow the pump to run. Build up in the pump or a piece of debris that has locked the rotor? That at least seems plausible. System air bound? Discharge piping flow check stuck? Doesn't seem likely as in 26 years with our heating system no air pockets have formed that required venting or affected system operation. No recent maintenance where the system was opened. I checked out a few of the upper register air vents and they push out solid water streams. The Taco air scoop high vent (only 1 yr old) is properly adjusted. This circulator pump does have an internal check valve assembly inside the discharge flange .
Other things to check or is it highly likely the pump motor is fried? I'm due for a furnace cleaning so I can probably time that with the circulator troubleshooting/replacement. Either I can do it the day before....or work with the burner tech.
Taco circ pump (no LED on my older version)
------
Misc: circulator is installed on the return side. The pump/motor assembly is mounted in standard/recommended positions as per Taco drawings....the impeller is mounted horizontally. The burner water jacket was replaced on warranty 9 years ago, so I'm not 100% sure if the circulator might have been replaced at that same time. If not, then it's 19 years old along with most of the Burnham furnace/boiler controls.