2 zone boiler one zone will only provide heat if other is on

Itsbroke

So I’ve got a 2 zone propane boiler and the #1zone works fine on its own but other #2zone will only send heat if zone 1 is on .

HomerJSmith

One flo-chek is in an open position and one is in an operating position. Which is zone 1 and which is zone 2?

Is this problem something new? Have you changed anything?

Maybe the weight is stuck, open up the flo-chek that is operational. That's the one with the short screw on top.

https://s3.amazonaws.com/s3.supplyhouse.com/product_files/Watts-0856760-Install-Instructions.pdf

It seems to me to be an unusual piping configuration.

hot_rod

so 1 circulator pumping into the return of the boiler, the other pumping zone 2 on the supply of the boiler?

Jamie Hall

For clarity in my mind -- since this may be a control problem. If zone 1 is calling for heat, the zone circulator runs and the boiler runs and you get heat in zone 1. If zone 2 only is calling for heat, neither the circulator nor the boiler runs? If both zones are calling for heat, the zone circulator runs and the boiler runs and both zones get heat?

Itsbroke

No this is not a new problem I bought the building a year ago and this is the way it’s always been .
Jamie yes you are correct 
so it I turn thermastat up for zone 2 ( while zone 1 is off ) you can hear things click in but the boiler doesn’t fire . 

If zone 1is on and I turn up zone 2 that I get heat in both zones

Jamie Hall

Ah good. Progress. Now -- there are zone valves? If so, what should happen is that the thermostat calls for heat and the corresponding zone valve opens. That should close what is called an end switch on the zone valve, and that, in turn, should turn on the circulator and the boiler (if the boiler aquastat is also saying go). What I'm wondering is... can you trace the wiring from the zone valve end switches and see where it goes? Maybe make a drawing of how it is wired? My suspicion is that the somehow the end switch from zone 2 is miswired -- or isn't working at all.