Tinny rattling sound coming from DHW circulator

In_New_England

The circulator on the DHW side


has been making a tinny rattling sound for quite while now. The best I can describe it as is tiny little balls rattling in a pipe.

Is this just air in the circuit, or is it on it's way out, and I should be prepared to replace the cartridge?

It's been doing this for a year now - I can't recall if it always did it.

Thanks!

hot_rod

Good chance there is a spec of debris in the impeller, or the close piping that doesn't flow through.
It sees a lot of water introduced into a DHW system, along with crud from the bottom of water heaters.

Might be worth disassembling for a look. does it have isolation valves nearby?

In_New_England

Sadly, the installer did not install isolation valves and I was not savvy enough at that time to insist on them. The only way I can get to that circulator is to drain the tank below that level. I have the equipment for it, but it is more of a barrier than if the circulator broke and I was forced to replace it.

HomerJSmith

How about a pic from the front. Could be a solder ball?

hot_rod

You may find a complete pump is less expensive compared to cartridge. Plus you get a new o -ring that fits and motor. Leave the body in place, swap all the innards.

Lots of newer ECM versions of recirc pumps now, smarter, less power consumption, should you decide to upgrade

In_New_England

HomerJSmith said:

How about a pic from the front. Could be a solder ball?

That's a very interesting idea - something mechanical outside the pump that's loose and getting rattled about - solder ball, loose nut/screw. Will check.

In_New_England

hot_rod said:

You may find a complete pump is less expensive compared to cartridge. Plus you get a new o -ring that fits and motor. Leave the body in place, swap all the innards.

Lots of newer ECM versions of recirc pumps now, smarter, less power consumption, should you decide to upgrade

I did some searching and decided that the Taco 005-020RP is the drop in replacement cartridge. Online at least, the cartridge was cheaper than the whole pump assembly and comes with a new O-ring. I would expect this. My plan was to rebuild by just swapping out the cartridge. This would save me plumbing work.

Your statement suggests I could look for cartridges of a different type - but I worry about figuring out what is a drop in replacement and what is not for the housing that I have.

SteveSan

@In_New_England The only cartridge assembly for your taco 006-BT4 is the 005-020RP. Like others have said it could be a piece of solder in the volute of the circ. pump. With the replacement cartridge you do receive a new O-ring and 4 bolts. Taco has a you-tube channel with videos and many others have how to change out the cartridge. If you have any questions, please give Taco Technical Support a call during normal business hours Mon-Fri 8am-5pm EST 401-942-8000

In_New_England

Thanks @SteveSan and others. Guess what: The circulator must have gotten wind I complained about it, because, I kid you not, I can't hear the sound any more. I'll keep an ear to it, but I'm pretty sure I've been around for a cycle or to of the hot water circulating (I heard the furnace go off, some one was taking a shower, and the circulator piping was really hot) and it was silent.

It's an old pump - I just found some paperwork that says the company that put in the boiler in 2012 re-used the hot water circulator from the last set up, so perhaps I should buy a spare cartridge as insurance ...

Larry Weingarten

Hi, Really hot and silent suggests that the impeller is stuck. Maybe that ball of solder got in the way. Is the pump moving water? If not, it’s time to take it apart. 🤠
Yours, Larry

In_New_England

Larry Weingarten said:

Hi, Really hot and silent suggests that the impeller is stuck. Maybe that ball of solder got in the way. Is the pump moving water? If not, it’s time to take it apart. 🤠
Yours, Larry

If the motor body itself was hot I'd be concerned, but I was referring to the pipe of the circulating loop that brings water back into the tank. Also, we are getting hot water. If the impeller was stuck I'd expect cold water.

mattmia2

@Larry Weingarten from his other thread we know this is a dhw storage tank that is heated through a tankless coil. There would be no hot water if this circulator wasn't working.

SteveSan

@Larry Weingarten Under normal operation they will run between 140-160 degrees. A good test would be to take an amp reading. A typical 006 according to the name plate should be around .54 amps. If drawing upwards 1.5x nameplate would suggest air or cartridge is locked.

In_New_England

@SteveSan are there "flavors" to the cartridge? In the photos some look SS and some bronze. Are they all drop-in replacements? Thank you.

SteveSan

@In_New_England the cartridge that you have 005-020RP is made up of a Noryl based material ( black in color ) found in our open loop circ. pumps and a typical hydronic heating circ. pump, like a 007-F5 would be made from a poly-pro material ( black in color ). Not all Taco cartridges are replacements for your 006-BT4, each one of our 00 series has a certain flow & Head design so the cartridge would be different for each model number.

HomerJSmith

A last comment, do you have a swing check valve close to the discharge of the pump? Could be rattling of the gate.

In_New_England

HomerJSmith said:

A last comment, do you have a swing check valve close to the discharge of the pump? Could be rattling of the gate.

Another interesting thing to check. There is no ball cock downstream (it goes straight into the tank) but I noticed that the pressure relief on the tank circuit is a long pipe that touches another pipe that's part of the DHW circuit. I've placed something soft in between to see if that stops the noise.

HomerJSmith

Definitely the last comment, I have had a situation where the stainless coil in the tank was rattling against its self. Get that mechanic's stethoscope.