Failed recirculating pump...cont'd

[Patricia T]

I recently posted a question regarding the failure of my recirculating pump:

https://terrylove.com/forums/showthread.php?t=7797

When I questioned my plumber regarding his not turning off the pump while the water to the house was off (for a different job outside, unrelated) he claimed it could not have been the reason for the overheat/failure since the pump would have continued to recirculate the hot water in the tank. I've tried to picture the schematic in my mind and I *still* think his turning off the water is the reason for the overheat/failure. Can anyone set me straight and offer more on this? I'd like to have a definitive answer before I challenge him on possibly paying for its replacement.

Thank you very much,

-P

 

[Dunbar Plumbing]

"Turning the water off" implies a possibility.

1. Was any hot OR cold faucets open when the water was shut off at the main?

2. If any faucets were opened and allowed a drain down scenario......I can definitely see that pump running without any flow of water to keep it from burning up.

A sump pump not sitting in water running continuously can destroy it/cause premature failure. I believe your situation mimics the same.

I'm always cautious when dealing with recirculatory pumps by shutting them down during pipe repairs and what not. For one it can cause a draw down of the water heater if the circumstances are right and two the cost of a pump that is simple to protect by merely flipping a breaker off.

 

[Sponsor]

 

[Patricia T]

Thank you very much for your reply. It seems logical, as confirmed by several plumbers.

I simply asked the plumber if he thought (not accusatory) if it could have burned up from the water being shutoff, but he rejected that idea saying "I was working with cold water -- not hot and it would be circulating out of the tank and back in." Hmm... what am I missing here.

Unfortunately, I do not have an answer as my old pump and replacement pump unexpectedly arrived in a box today with a note from him that I am basically on my own. I don't know what to make of this (?) All I did was ask him....

Thank you,

-P

 

[Dunbar Plumbing]

He's sounding and acting GUILTY as charged. Otherwise he'd be a little more acceptable in the matter. It seems the one-liner statement isn't very convincing.

 

[Patricia T]

Thanks, Rugged. I came to the same conclusion, but feel badly about the whole deal. If only he had stood up to the mistake all this could have been avoided and no hard feelings. Nice fellow, good work and I would have certainly recommended him to neighbors and friends.

And still without hot water... <sigh>

-P

 

[MrRedyTemp]

Recirculation pumps should be powered off anytime the homes main water supply is shutoff. Recirculation systems require enough water pressure to maintain a "constant / air-free" supply of water. Recirculation pumps are not designed to operate like a well water pump. By shutting off the homes main water supply, and then performing work on the homes cold water line you can expect; 1. water will drain from the cold water line. 2. air will enter into the cold water line and possibly through the Grundfos thermostatic bypass valve.

Circulation pumps require water flow to keep them from over heating. I don't know if your system was a closed loop (dedicated hot water loop) or whether it shared the cold water line. If the cold water supply valve to the water heater was closed while work was performed on the cold water line, this may have prevented water from exiting the water heater through the recirc pump and thereby preventing cooling the pump.

Everybody makes mistakes. Perhaps manufacturers like myself should start supplying tags or stickers that inform anyone at the main shutoff valve and water heater.

"WARNING: THIS SYSTEM UTILIZES A HOT WATER RECIRCULATION PUMP. POWER OFF PUMP WHEN SERVICING."