Hot Topics: Recirculator Pump Shouldn't Be On Fire

A burnt-up hot water recirculation pump.

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If you have to wait at an open tap for the water to heat up, a hot water recirculation pump can solve that issue, saving you time and money and water. But there’s all kinds of heat and gasses around your water heater, so if things aren’t installed properly it can get ugly, or even deadly. Let the Forum take a look to spot the dangers.

Original Post: Grundfos Comfort Series caught fire

noblehouse Member

I have a Grundfos Comfort Series hot water recirculating pump installed on the water heater. It was here when we bought the house so I don't know how old it is. A few days ago we noticed we weren't getting hot water, and I went out to take a look. The timer seemed to be set correctly and it was plugged in, but I didn't have time to investigate further. A few days later I went out to look again, and saw that at some point it caught fire. The timer side of the pump was completely burned away. I don't know when this happened, but I'm lucky the house didn't catch fire.

Until this happened we were pleased with the system--there's a drought here in California and we were wasting a lot of water waiting for the hot water, so I'd like to get another. But now I'm hesitant -- what would cause this to happen? Is this a known problem with Grundfos pumps?

Highlights from the Thread

Rockledge Member

Wow. It looks like some serious over-heating was going on there.

I can only speculate as to what caused the pump to cook like that. Faulty wiring/electronics? Seized motor? Pump installed too close to exhaust vent?

NJ Trooper Forum Topic Moderator

Not a known problem that I'm aware of...

I myself would be on the phone to Grundfos... that's serious shyte ryte there...

lawrosa Super Moderator

It’s not installed properly... Really??? Placing the motor right on top/touching of the flue, anything would overheat. (From what I see anyway.)

I would not look for any warranty, and especially don’t show them that picture... Plus you need a straight piece of pipe off the heater not an ell directly on the draft hood.

I would look to go after the installer of said heater and/or pump install...

Last you may want to look at electrical issues and the outlet the pump was plugged into...

Just my 2 cents is all...

noblehouse Member

Thanks all for your insights. Regarding the location of the pump, it's not actually touching the flue...that's just the perspective of the photo. It is pretty close though. But that's where the hot water pipe is. Should the pump be installed somewhere else?

Hot Topics, Recirculator Pump Shouldn’t Be On Fire, hot water

My guess is that the installer was the previous homeowner. We know he was quite the do-it-yourselfer (and not in a good way). We've had to correct other instances of his handiwork.

Hot Topics, Recirculator Pump Shouldn’t Be On Fire, hot water

lawrosa Super Moderator

Oh my... Clearly you have draft issues... Look at the red and blue inserts at the h/c nipples. You see they are melted? That means flue gas is rolling out and into the home... You have chimney blockage or lack of draft...

Please have a working CO detector for you and your family's safety... (You can Die!!!!)

The flue needs to be checked, and/or heater, and corrected ASAP!!!!

(That’s your over heating issue IMO)

Your pump is the least of your concerns at this point...

NJ Trooper Forum Topic Moderator

Yeah... those new pics tell all!

Where does the flue pipe go after it leaves the pictures?

Second the CO detectors... loud enough to wake NJ Trooper out of a Sam Adams Coma.

I bet there's no “earthquake straps” on that unit either.

noblehouse Member

Wow, this is why you ask the experts.

We do have CO detectors in the house. The water heater is not accessible from within the house. It is in a closet, accessed via a door on the exterior. The door is vented, so fresh air gets in.

We had the entire roof replaced last year, including the plywood, so it was all opened up and we did look at all the vents at that time. I am pretty confident that the flue pipe vents out the roof.

I've ordered a new pump and I intend to have a licensed plumber install it. I will ask him about the flue setup as well.

Thanks for all your advice.

PJmax Forum Topic Moderator

Since that is single wall flue pipe... If it goes into a wall it must be in some type of chimney.
If that flue pipe goes into a wood or sheetrock wall then it requires immediate attention as it could be a fire hazard.

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