Fried boiler Taco (007) F5-7IFC circ pump motor?

[69GTX]

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)

------

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.

 

[johnnydc]

I have hot water heat myself. It has a Taco circulator pump. I've been at the house for 22 years. The same pump. Very reliable. As for the problem you are having, I don't know. My pump gets very hot, But so is all the piping. I would think if the water is not heating up, The pump should be cool to the touch.

 

[69GTX]

I've never put my hand on the pump when a normal heat cycle was in progress. My bad for that. Other blogs and threads I've read have commented that these type of circulators do tend to run hot, up to 40 deg F hotter than the surrounding fluid, which means 210-225 deg F. during a heating cycle. It's rated for 240 deg F. Mine is definitely not seeing any flow though.

 

[eljefino]

I had this happen and had your symptoms. You can feel a stalled motor, it kinda "tickles" and vibrates instead of the happier feeling of a running one.

 

[wog]

Taco pumps are reliable,but they do go south eventually . Symptoms say pump, the housing will get very hot so that you can t touch ., when in working order you can leave fingers on it for 10 to 15 seconds without burning yourself. Make sure your pressure is 12 to 18 pounds pressure.e. if air bound you will get some gurgle on other zones. .isolate pump and get new one. ,if it is rusted on flange bolts get a set of bolts in case you have to saw old bolts. Then fill and purge boile loops one at a time. Don t fill hot boiler fast with cold water you could crack boiler. Initial filling let water in easy,then when up to pressure purge shut power off to boiler when you go get circulator give time to cool a little.

 

[fdcg27]

Sounds like it must be the circulator.
They're usually not that costly or difficult to replace.
Can you valve the outflow and return lines off? This will allow you to avoid draining the whole system although you'll still have to bleed off air.
The one on our boiler has seen more than twenty years in service.
Maybe I should replace it before the heating season just as PM?

 

[69GTX]

Never heard gurgling on my system. Just some bangs and creaks as the system starts up. Boiler operating pressure per the installed gauge is 20-30 psi. Water regulator is rated at 10-25 psi (set 12-15)....which technically wouldn't get water into the boiler. Maybe one of them assumes "psig?" Flanges and flange bolts look good w/o signs of ever leaking, should come apart easily.

Unfortunately, no isolation valves near the circulator, so lots of water will drain out. There are adequate drain valves to bleed out air. I'll just let the entire system cool down before doing anything with the circulator.

 

[wog]

Good plan! Some new taco s you can get a rebate from taco ,conservation another smart! Appliance. Go on web and checkm,supply houses were showing displays about it.good luck

 

[walterjay]

If you have or can borrow an amprobe you can check the motor amperage. It should be around 1 amp draw. If it is using much more than that, the motor is locked up and drawing high amperage and will have to be replaced.

 

[Andrew1972]

Mine does that when system goes air bound. The idiot HVAC who improperly install my indirect hot water heater showed me how to purge air(open faucet at exit) and then it operates normally.

 

[JHZR2]

Not a very good picture in the linked document. IIRC, there's often a cap or a screw of some sort on the round motor end, that you can remove to verify that the unit is spinning. Sometimes they can get stuck, especially after sitting three seasons. Getting in there will allow you to see if you need to give the impeller some help...

You should be able to hear it, but they tend to be very quiet... If yours is a multi-speed, the delta in sound may help.

 

[69GTX]

Success? Not so fast.

I turned up the thermostat and the burner kicked on for a heating cycle. What luck? No idea why it would do that now. Went down to the basement and checked the 3 high point drains in the basement and they all blew straight water. Then I felt the discharge piping and it was hot 5 ft further down the line than if only the hot water heater was on. But that was it. The return line was stone cold and the burner was up to max temp of approx 220 deg F and turned off....a 2 min cycle rather than a typical 5-10 min. The pump motor was getting real hot again. 5 ft of flow is better than nothing....lol. Or was that just induction heating from the burner getting 40 deg hotter for a home heating cycle vs. a hot water cycle? For a minute there, I thought I was going to luck out.

This Taco pump is a removeable cartridge unit. The only option is to unscrew the 4 flange fasteners and pop out the sealed motor/impeller assembly. No other way to see inside or give the shaft some help. WIth the cartridge costing nearly as much as the entire pump/housing assembly, it's more cost effective to buy the larger unit.

 

[wog]

Buy complete pump, changing motor might not work .sometimes they don t seat good and go south in short time.put hose in a bucket out side and let water run until no bubbles are coming out. It takes a good 5 minutes or more to get a smooth flow. While system down,change canister vents on boiler if they are limed up or rusted. These vents will help eliminate air in loops or zones of heat.purge with power off so you get as much air out as you can.most of the time the highest points get airbound and you need to force air out,elevating pressure helps get job done . Loops or loop is air bound as well as pump might be toast.have you installed new pump? If not purge loop and try heat ,if not moving then new pump is next.

 

[69GTX]

Thanks Wog. Still can't explain why apparently the heating system (and the pump too) ran/pushed water for at least a few seconds yesterday. Before I take the pump assembly out of the system, I'm going to have a new one sitting in a box, ready to go. Fortunately, I don't house heat again until Sept/October. I vented the system in numerous places and got not a single air bubble out.

 

[sleddriver]

I have a Taco HW pump on my solar water heater. If I recall correctly, you don't need to replace the whole pump, just the insert cartridge. Much cheaper that way.

 

[mk378]

It could be the stator assembly or the cartridge. Most likely there is dirt in it making it unable to spin. You don't need to take the body out of the pipeline to swap the other parts. If you do start messing with the pipes, adding isolation valves would be good.

 

[L_Sludger]

Today I learned that there is a company that manufactures steam heat central heating pumps out of an iron casting. They paint their product green and are known by the name 'Taco' to enlightened persons of tribological repute.


Because before I clicked this thread, I had no idea that a company, any company, was named Taco. A company named Taco, that manufactured recirc pump motors for central steam heating systems, and that people threw their brand name around as if it were a hot topic of conversation.

Or even that a burned-out Taco-brand steam or water pump was known as a 'fried Taco'.


Strange times we live in, times that require context. Context that's desperately needed in order to survive and sound knowledgeable.

 

[69GTX]

Originally Posted By: L_Sludger

Or even that a burned-out Taco-brand steam or water pump was known as a 'fried Taco'.


Oddly, I never once thought of that association when presenting this thread. "Fried" is a common "slang" term used in the power industry when motors fail.

The difference in price between a cartridge assembly and the whole pump/motor/cast housing w/flanges is only around $16-$22 via Amazon or Home Depot. Considering that a housing can get eroded and/or corroded from cavitation for example, ....buying the whole thing would seem to be the best choice. What if after buying the cartridge insert you find out the pump casing has a problem? Then you have to buy the entire assembly anyways.

 

[bmwpowere36m3]

007 Tacos are probably the most ubiquitous circulators in hot water systems... should be under $100. I usually buy stiff from my local supplier who has been very good to me when I redid my entire system. However Supplyhouse.com is also very good and quick (a lot comes from NY warehouse).

The pipe being hot only 5' is either gravity or conduction... Do the circulator flanges have isolation valves? Sounds like a seized circulator... but it could be an obstruction in the piping as well. I pull the circulator and inspect it. As well flush the circuit ensuring clean flow.

 

[69GTX]

As soon as I get my burner cleaning set up, I'll pick up a circulator. For me, no valves around the pump. But, it's such a small system (150-175 lineal feet of 1" pipe) it doesn't take all that much do drain/fill it (5-6 gallons).