I had some plumbers take a look at my hydronic system to discuss splitting the single zone. They proposed to use separate zone pumps. In retrospect the other way to do this would be with zone valves. Any reason to prefer separate zone pumps and a lot of extra pipe?

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    @Ack hydronics not hydroponics. Not the same thing and definitely on-topic for this board.
    – jwh20
    Nov 10, 2020 at 21:01
  • go with two pumps .... the bonus is redundancy ... if you add manually operated crossovers, then the whole system can be configured run on a single pump, in case of pump failure
    – jsotola
    Nov 10, 2020 at 22:37
  • Why would using pumps entail a bunch of extra plumbing? That doesn't make any sense.... Nov 11, 2020 at 1:46
  • Because when you add a zone pump you have to create an entire loop for each zone. If your individual radiators are piped off the zone loop using monoflow tees, then to turn on and off each radiator individually you just have to put a valve before the radiator. As it is, I ended up splitting on zone into 3, but I now wish I had added another separate zone for the basement radiators. Mar 9, 2021 at 19:42

1 Answer 1


The problem with one pump and valves is that you can't ensure that you always get the flow you want when one of the valves is closed vs. both open. So things can be difficult to balance.

With two pumps there is more control and you should get more even heating.

Unless you have a strong reason to do it another way, I recommend you take the advice of the plumber you choose to do the work. Otherwise it could end up being a "you told me to do it this way" scenario.

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