Need help with Primary/Secondary Water Loops

josephny

Several years ago I set up an IBC SFC-199 for DHW and a single zone under-floor hydronic heating.

I decided to add 5 additional zones upstairs and just built the system shown below.

I thought I had it all correct, but I can't get it to work. Using a Caleffi ZSR104 and a 103 (supply store did not have a 6 zone in stock) set up (I believe) as per the instruction manual, with an Ecobee on each zone, sure looks like the system is properly calling for heat.

But, I don't think there is any water flowing.

A thought that came up was whether I needed another pump somewhere on the secondary loop?

Can someone take a look at my design and tell me what's wrong?

Thank you!

hot_rod

Check valves in all the pumps!
purge valves somewhere?
Is there a pump inside the IBC?
piping is correct

josephny

hot_rod said:

Check valves in all the pumps!
purge valves somewhere?
Is there a pump inside the IBC?
piping is correct

All valves checked (confirmed open)

Purge valves on each return line. Should I open them to release water and/or air?

Yes, IBC SFC-199 has internal primary loop pump.

Thank you for the piping confirmation.

I got the unit to fire up, but the heat does not circulate at all into the secondary loop. The primary loop hot side gets a little warm, but not like it is passing 160*F water through it's short copper pipes.

hot_rod

The boiler injects hot into that header. The zone pumps pull from that header. Sounds like you need another purge. Do one zone at a time

josephny

Hot_rod to the rescue again!

system needed to be purged.  

Not that I knew how to do that, but I figured it out (at least enough to make it work). 

Now I’ve got heat.  

Thank you very much!

hot_rod

Once you have flow in all the zones, the air separator will finish off the job of getting dissolved air out. It could take days.
Leave the fill valve open for a period of time to add water as the remainder of the air comes out.

josephny

Got it.

I was sort of hoping that air separator would take care of the initial big purge, but I see that was fantasy-thinking.

I thought the fill valve was an automatic device to bring the pressure up to a preset level? Do you mean mean the manual lever on top that I pull vertical to bring in more water should be left in the vertical position? Pressure would (I assume) rise to the house water pressure of mid-30's PSI. Is thank okay?

I did not use antifreeze initially and now am rethinking this decision. Can I simply open a return valve on one of the zones to remove existing pure water while pumping in antifreeze on the supply side?

hot_rod

No need to lift the lever on the fill valve, it should be pre set to 12-15 psi. Fast fill lever is just to fill and purge the first time.

Why the glycol consideration? Messy, expensive, maintenance prone, and some efficiency loss. In some cases a larger circ is needed.

josephny

I'm concerned about freezing. I have tons of sensors with alerts, but I am often far away from the location.

I thought it was cheap insurance.

Should I not use antifreeze despite 1200' of 3/4" pex running throughout the 3 story home carrying heating hot water?