Hot water troubleshoot and recirculating pump question

[wopachop]

Ok dont laugh. Was with a restaurant owner at a local plumbing supply and the guy was super helpful. We bought the grundfos recirculating pump. Theres an upstairs bathroom where we planned to put the bypass valve. Now the funny part....we both thought he said the pump could be mounted right under the bathroom sink. Not sure why i didnt confirm. Thats like, impossible right? Supposed to be right at the heater on the hot side? Will it even work for this application since its 1" and the pump is 3/4". Wish i had looked at the heater before we went. We were going just for faucets. Pump was an add on.

The troubleshooting part. There was a community water heater. Some issue happened im not sure what it was. But the owner paid to have her own tankless heater installed inside the kitchen. She says its never worked properly. Just cant get hot water to the faucets. It takes forever she says. Was thinking about it this morning. Is it possible the guy plumbed it so that the hot water is still traveling all the way back to the original community tank location? Shes had professionals come test the heater and they say its ok. But nobody can figure out why no hot water to the faucets. We were hoping the recirculator will help. Now im worried its too small being 3/4" and the tankless is 1". Can i use the pump? I opened up the bags dont think i can return.

 

[Geofd]

Check your pre rinse faucets make sure the hot and cold handles are always off when not in use, check your janitors closets if there is a chemical soap connection make sure the hot and cold handles are off ECO
LABS makes a fitting that threads onto the slop sink faucet that prevents crossovers it's called a side kick, check the easy stuff 1st
The best way to prevent crossover is to install check valves on the hot/cold on the piping feeding the pre rinse facet

 

[wopachop]

Are there times a check valve is part of the faucet? Or always a separate device?

 

[Geofd]

Are there times a check valve is part of the faucet? Or always a separate device?

Yes t+s brass makes them but they can fail just like any stem

 

[wopachop]

I just watched a video shows a pump installed under the sink. I'm still confused.

Can this style pump with the valve both be installed at the furthest sink?

 

[breplum]

For sure we have recirc pump systems where the pump mounts under the sink. Taco and Laing both have those products I’ve installed. Of course you need 120V under the sink.

 

[wopachop]

Thanks. But can the model we bought with the separate bypass valve be installed under sinks?

Video I watched the pump had the valve built into it.

 

[breplum]

you are likely right, you bought the wrong pump. More like these TacoGenie products is what you'd need.
You could mount a pump at the tankless. I never do that any more and only buy the tankless models that have built in recirc. pumps on board with settings to control the parameters. Navien is the only brand I deal with any more, but Noritz makes models too.
Aftermarket mounting of pumps is not efficient and a waste of good money IMHO.
or

 

[wopachop]

I'm guessing in theory you can mount the pump in the bathroom sink? Feeding into the hot side of the bypass valve?

Me and a lady were both positive he said several times you can just lay the pump on the ground if you wanted.

Or I can get adapters and hook to the water heater.

Watching videos I agree getting a tank less with a built in pump would be a no brainer.

I should find a model number and confirm it doesn't.

 

[Geofd]

Have you checked yo see if the pre rinse +janitors faucet aren't adding to your issue????

 

[wopachop]

Can you please help explain the janitors sink and what to look for? Should I be seeing a 1 way valve plumbed into the copper line.

We replaced the prerinse faucet. Also tested it by turning off the supply valve.

Still only getting warm water. Finally tested it myself. She says other plumbers have all said it could be crossover. But nobody can point to a spot and say there....we can replace that and fix the issue.

There were 2 professional plumbers there yesterday. The jetted the drains and also installed the new prerinse faucet. They can't give an answer either. It's a bummer I feel bad for the owner. She's trying to hire and pay for a fix but nobody can fix it. I'm more a general handyman. I appreciate all the help her. I told her the smart guys on the plumbing forum have been helping a ton.

 

[wopachop]

There a dishwasher near the prerinse sink.

Then what I think is the janitors station near the mop sink.

 

[wopachop]

Below are the pipes under mop sink that feed the janitor chemicals.