DHW piping into boiler

[Charlie T]

I recently had a plumbing company replace both my HW boiler and the boiler mate style Hot water heater. I believe they plumbed the return feed from the HW heater to the boiler incorrectly.

The output of the HW heater circulator pump is piped before the heating circulator pump so that the HW return must flow thru the heating circulator on it's way back to the boiler. Shouldn't both pumps be effectively "T'd" into the boiler return line so that it isn't necessary for the HW circulator to force the water thru the second pump (baseboard circulator) to return to the boiler?

Thanks for your anticipated replies

 

[frodo]

no you should not be pumping through another pump,

 

[Diehard]

I recently had a plumbing company replace both my HW boiler and the boiler mate style Hot water heater. I believe they plumbed the return feed from the HW heater to the boiler incorrectly.

The output of the HW heater circulator pump is piped before the heating circulator pump so that the HW return must flow thru the heating circulator on it's way back to the boiler. Shouldn't both pumps be effectively "T'd" into the boiler return line so that it isn't necessary for the HW circulator to force the water thru the second pump (baseboard circulator) to return to the boiler?

Thanks for your anticipated replies

I think a couple of pictures would help clarify exactly what you are describing.
I am under the impression that a "boiler mate style Hot water heater" is a unit such as a SuperStor indirect water heater or a Amtrol Boiler Mate, which are fed by a heating boilers water through a pipe coil within the Domestic Hot Water Tank.
If that was your case then the diagram shown above wouldn't apply.

 

[frodo]

I think a couple of pictures would help clarify exactly what you are describing.
I am under the impression that a "boiler mate style Hot water heater" is a unit such as a SuperStor indirect water heater or a Amtrol Boiler Mate, which are fed by a heating boilers water through a pipe coil within the Domestic Hot Water Tank.
If that was your case then the diagram shown above wouldn't apply.

that is exactly what that diagram is . it is heating water through a pipe coil within the Domestic Hot Water Tank.

 

[Diehard]

that is exactly what that diagram is . it is heating water through a pipe coil within the Domestic Hot Water Tank.View attachment 21007

Then the piping shown is incorrect. It shows the Domestic water interconnected with the heating boiler water. It would be okay if it was a tankless but it wouldn't be done through a tankless system.

 

[frodo]

no. it does not show the domestic water interconnected with the boiler water
it shows the boiler water going inside the unit. threw a coil, that is called a heat exchanger
the boiler water and domestic water are 2 separate systems

My diagram is only showing one of the systems. I assume because you can not see the other piping that you are confused

maybe this will turn the light bulb over your head on

 

[Diehard]

Look again! Are you now saying the recirc is not domestic but heating?????????????

 

[frodo]

I recently had a plumbing company replace both my HW boiler and the boiler mate style Hot water heater. I believe they plumbed the return feed from the HW heater to the boiler incorrectly.

The output of the HW heater circulator pump is piped before the heating circulator pump so that the HW return must flow thru the heating circulator on it's way back to the boiler. Shouldn't both pumps be effectively "T'd" into the boiler return line so that it isn't necessary for the HW circulator to force the water thru the second pump (baseboard circulator ) to return to the boiler?

Thanks for your anticipated replies

baseboard is the thing on the wall that produces heat when it is cold outside
it is a separate system from potable water

 

[Diehard]

The baseboard heat is piped off the circulating line between the boiler and the water heater??????

That's why my original comment, to the OP, said, "I think a couple of pictures would help clarify exactly what you are describing."

 

[Charlie T]

Hello Guys/ Girls
Thanks for the replies. I should have posted a drawing to clarify. In the drawing below, my DHW "heat exchanger" circulation pump is currently plumbed at point #1 so that it's forced to flow thru the circ pump for the baseboard heat. I believe it should be plumbed to point #2 so it returns directly into the boiler. Am I correct in this thought?
Thanks for the help
Charlie T

 

[frodo]

You do not want to pump water through a non running pump
the impeller is going to change the gallon per minute you are pumping
i added ck valves to stop water from circulating backwards through the zone that is not calling for heat

 

[Charlie T]

You do not want to pump water through a non running pump
the impeller is going to change the gallon per minute you are pumping
i added ck valves to stop water from circulating backwards through the zone that is not calling for heat

View attachment 21013

Thank you for your assistance. I now need to go back to my plumbing contractor and ask him to pipe the system properly.
I appreciate the time it took to help me

Charlie T

 

[frodo]

what i do not understand is the use of 2 pumps, when one would have been just fine
it can be on either supply or return


opps. i did not add 2 --$40.00 zone valves

 

[Charlie T]

Its a 4 heating zone system with Taco zone valves for each zone. I would imagine the separate pump for DHW is to allow for priority as well as to ensure sufficient hydronic flow during periods of high demand. Other than that I'm not sure other than to say the old system was set up with 2 pumps so they just copied it. I do believe they made a mistake with the proper piping of the circ pumps which started this discussion.

 

[Diehard]

Yes, it wouldn't make a lot of sense to consider a one pump system at this stage of the game.
Get the plumber to fix that screw up and add check valves as pointed out. The circulators may have them built in.