Lochinvar Knight with multiple heating zones

myqhenryt

I'm currently in process with the install of a Lochinvar Knight WHN-110 with three heating zones (with circulators) and a DHW zone. One of the heating zones is a hydronic coil in our air handler (first floor), one is Warmboard radiant (part of first floor), and the other is baseboard (basement). We had initially purchased a Taco SR504-4 to control the different zones thinking that we'd utilize a single temp for the heating zones. We'd have a thermostatic valve for Warmboard to reduce the temp for that zone.

But now we're thinking that it would be best to utilize multiple temps here as Lochinvar supports it, but there's a bit of confusion around the setup for multiple temperatures via the boiler. Given what we currently have, is it possible to configure multiple temps? Or do we need to without Lochinvar's Multi Temp Loop Control or some other controller?

Thanks!

Paul S_3

You need to mix down for the radiant zone

Paul S_3

Just saw that your using a mixing valve

myqhenryt

Yup, we have a thermostatic mixing valve for that. Note that the radiant is more for comfort in that area of the home which is over an unheated crawl space.

I guess the question comes down to handling the multiple temps for the coil and baseboard. Best that I can tell, we cannot do this out of the box with the Lochinvar boiler without purchasing additional equipment -- does that sound right?

Brewbeer

The WHN allows you to program different temperatures (minimum and maximum) for three different zones. Take a look at page 20 of the manual: lochinvar.com/_linefiles/WH-SER_Rev%20L_100161828_2000019118.pdf

That having been said, if your different zones require vastly different temperatures to function acceptably, and they call at the same time, only one of the zones will work as intended, and the other zones won't work well until the first (controlling) zone stops calling.

myqhenryt

Ok, this is where I'm confused. You can program three separate temps as you've noted, but how do those correspond to the actual circulators? For example, how does the boiler know that the SH1 temperature is for the zone 1 circulator? I might be missing it in the wiring diagram, but is there a wire that runs from the boiler to the zone relay to trigger the appropriate circulator based on demand from the thermostat?

Brewbeer

myqhenryt said:

is there a wire that runs from the boiler to the zone relay to trigger the appropriate circulator based on demand from the thermostat?

Yes, see the wiring diagram on page 55 of the installation manual:
lochinvar.com/_linefiles/WH-I-O-Rev%20W_100161819_2000019113.pdf

Boon

oops. nevermind

myqhenryt

Brewbeer, I've seen the diagram. But where I'm confused is around wiring those three heating zones from the boiler. It appears that there is not a way to utilize a Taco SR504-4 in this setup. If I'm understanding things correctly, the only way to make this work (with multiple temps) is having independent relays for each circulator. Each relay would be connected to the corresponding 'HEAT / LOOP DEMAND' connection on the boiler. We'd also want to make sure that the radiant loop has a mixing valve as the loop with the highest temp will take priority with this setup.