hydronic heat for the barn - part 12

Once all the plumbings are done I proceeded to install a 4-plex with the dedicated 120Vac circuit. Installed also is a 24Vac HVAC transformer for used with the thermostat. Then I could begin to fill the system with glycol mixture and purge the hydronic system of air.

I used the 120Vac diaphragm pump to fill the system first

soon I would found many leaks that need to be addressed

the 5-gallon bucket made mixing and filling easy; the process took most of the day

this barb end gave me a lot of grief and I simply couldn't stop the trickle of leak; it is a sprinkler barb nipple designed not for 60 PSI of pressure

the spiral barb is for easy of pushing into sprinkler hose and not to prevent leak; there is only one barb at the end for stopping leak

I calculated the system volume to be 40 gallons so I ordered 20 gallons of antifreeze to achieve a 50% mix ratio. I was within 2-3 gallons of accuracy.

the poor diaphragm pump had a hard workout pumping 40 gallons

the installer's mode allows me to switch on the internal pump and the secondary loop pumps to bleed the air through out the system properly

but soon I discovered the pump's one flange seal was pinched and cause a big leak

switching on the primary and secondary loop pumps to purge the remaining air

Once I was satisfied that all the air in the system had been purged I proceed to fire up the boiler for the first time. You don't do this unless you have triple checked everything and very confident there are no pockets of air in the system.

switched on the pumps via installer's mode functions

Next is the moment of truth - ignition of the boiler. 

we have ignition!

I opened the valves on all eight loops. As the 4000 square feet of slab floor was in the low 40s the boiler should be firing at close to the worst case BTU capacity for the barn. The system will be much quieter once the floor zones reach the target temperature. The loops nor the pumps have yet to be fine tuned and balanced.

all eight loops wide open

Firing up the boiler is a giant milestone for me after all the planning, design, procurement, and installation. There is a lot more work ahead to fine tune the system, get to know the boiler and assessing my choice, verifying and validating my design's versus the desired goals of it being a supplemental heat to the LG mini split heat pump system.

Each of my radiant loop is 500 feet which is pushing the limit of 1/2" PEX. Also I set out to design the most cost effective hydronic heat system by keeping the parts list to the absolute minimum and take advantage of my collection of parts.