hot water slow after pipe+valve replacement

[waterstuff]

Last week we had a pinhole leak in the supply line to the gas water heater. The plumber replaced the segment of the leaky copper pipe, the check valve, and a ball valve. All else remained the same. (the recirculating pump's flow speed, pump timer settings, and the water heater thermostat setting).
Now the hot water has become very slow to reach our faucets through the house. As if the pump is not working properly. But when I check the pump it seems to be spinning ok.
I've increased the pump speed, and the thermostat, but to no avail.
The WH and the pump are 8 years old. They were working fine before the pipe/valves replacement.
What could be the problem?

 

[Twowaxhack]

The impeller of the pump may not be spinning but the motor is running.

So no water is being moved.

Could there be air in the system ?

 

[waterstuff]

It sounds likely. It is also somewhat intermittent. Most of the times the hot water is very slow. But a few times it flows ok, as it should be with the pump timer on.
I'm not sure I can easily trouble shoot the impeller, or bleed any air. I think I will call the plumber to address these.

 

[JG plumbing]

The recirculating pump doesn't supply water. The water should get there no matter what the pump is doing.

Is this happening at every faucet?

If your check value isn't closing all the way it could slow your water down.

 

[waterstuff]

It happens in every faucet.
So maybe the new check valve is defective?

 

[JG plumbing]

It could be. Sometimes the manufacturer puts something in the check valve to keep it from slapping around during its journey from the factory to your house. There could be something stuck in it.

It should be a clean shot from your water heater to your fixtures. After the fixtures then it's the check valve and the pump. If the check valve is open the water can run past the fixtures and head back toward the water heater giving the illusion of low flow.

Or a different valve isn't open all the way.

 

[Twowaxhack]

If the check valve is open the water can run past the fixtures and head back toward the water heater giving the illusion of low flow.

Huh ?

 

[Twowaxhack]

I’m assuming when the OP says his hot water is “ slow “ that he’s referring to how long it takes to get hot once he turns on the hot faucet. Not a problem with flow volume.

 

[Twowaxhack]

If the check valve is stuck open and the pump isn’t operating ( impeller not moving water ) you can get water flowing backwards through the return line to the fixtures from the bottom of the water heater.

 

[waterstuff]

Yes, I meant it takes a long time for the hot water to come to the faucets. It used to be a few seconds, with the pump speed at "Low" and the pump timer set to run 15 min in each hour. But now it takes a minute for the hot water!
I checked the hot water pipe loop and it is lukewarm. Hence no recirculation. Even when the pump is spinning at "Medium" speed.
Hence it must be the check valve is defective. Or it was put backwards??..

 

[Twowaxhack]

Take some pics for us.

I think you have a bad pump. That’s my guess.

 

[waterstuff]

Here it is:
I cannot see a flow direction on the check valve. But the print is upside down, which means flows away from the WH??..

 

[JG plumbing]

OK yeah. I assumed flow issue. Yeah it's air then, lol. It can be difficult to bleed the air from a recirc system of the valves aren't specifically placed.

My bet air.

 

[JG plumbing]

The check valve should let water flow to the water heater. The letters don't necessarily indicate the direction of the valve. It's all about the arrow. The arrow should be pointing the direction of flow toward the water heater.

I'm sure you pump is right, but that picture doesn't show a lot. We need to see the volute of the pump. Aka the other side. The water should flow in through the center and out through the side.

 

[JG plumbing]

See how the bottom flange is letting water into the center of the pump and the top flange is ejecting the water out (I realize there's not water in the picture).

That's how I tell which way a pump is set.

So it's either the pump is set backward (not likley)

The check valve is backward (not likley)

Or your pump is airlocked (likley)

 

[waterstuff]

The pump is set the right way, since we got it installed 7 years ago.
So I think the new check valve is installed backwards...with all the repercussions this error implies.

 

[Twowaxhack]

Where is the check valve ? Take a pic

 

[waterstuff]

The check valve is visible between the grey foam insulation. The bronze with the text NSF/ANSI.
I cannot see a directional arrow. But I think it is set backwards.

 

[Twowaxhack]

take the insulation off and take a pic

 

[waterstuff]

Check valve: