Tips for proper air elimination and start-up

Connecting to the panel:

After mounting your RHT hydronic panel in the proper location you will need to proceed with the following steps:

• 1. Confirm all circuits from the radiant panels, radiators or other heat emitters are connected to the Supply and Return system manifolds in the respective heated areas.
• 2. Connect the Supply and return lines from the Boiler piping (Primary/Secondary) to the system manifolds.
• 3. Connect the combination Backflow prevention device/pressure reducing valve (make-up water valve). Typically this is supplied with a ½" water line connected between the air eliminator and expansion tank.
• 4. Filling/Purging air from the Boiler and radiant/radiator system as described below

Filling the system & purging air:

Close the isolation valves on both Supply from and Return to the boiler. Open the system fill, and set the pressure reducing valve to full street (supply) pressure.

Utilize the isolation valves on the secondary supply circulator pump flanges, and return ball valve boiler drains to force water through the supply side pumps out to the circuit manifolds, and back to the closed ball valve on the return side. This will force air & water out through the associated boiler drain.

Systems with more than one heating zone should be purged one zone at a time. Each zone being purged should also be purged one circuit at a time. This will allow the maximum flow through each circuit, forcing as much air out of the system as possible. This can only be done if the return manifold has isolation valves installed on each circuit. Start by closing all of the circuit isolation valves on the return manifold, except for the one you are purging. If you are zoning with zone valves you will need to manually open one zone valve at a time, starting with the zone you are purging. After a circuit has been purged, and has no visible air bubbles for at least one minute, close this circuit valve and open the next isolation valve on the distribution manifold.

Once you have purged each circuit on a zone, it is time to move on to the next zone. After all zones have been purged, the boiler drain can now be closed. The automatic make-up valve should then be placed back into normal operation mode. Re-open both of the full port ball valves near the inlet and outlet of the boiler, and the purge T. The last thing to do is set the system pressure at 12-15 PSI. If the system pressure is higher than you want, bleed some water through the boiler drain valve. Any small or dissolved air bubbles left in the system will be -expelled by the air separating device located near the boiler. By following this simple procedure, you will have a quiet and smooth running system.

All hydronic systems must be properly purged for the system to function at 100% efficiency and design. The predominant number of the Boiler System related call backs received industry-wide are caused by residual air remaining in the system. Air left in a hydronic system is usually associated with noises in piping, low flows, corrosion, uneven heat patterns, pump failure, and other issues.

Electrical wiring:

The boiler, system control logic and thermostat wiring should be connected by a qualified technician as indicated in the manufacturers wiring diagrams.

*Ensure that no power is applied to the boiler or controls until it is confirmed that the system is completely filled with water and the air is eliminated to avoid element burnout and control board or pump failure. This would be similar to filling a Hot Water heater with water before connecting electric power to it.

Starting and operating the boiler:

Your boiler may come equipped with a built in outdoor reset control and sensor, this should be installed as an energy saving option to increase fuel savings during the shoulder heating season months.

Create a call for heat one zone at a time, by setting the area thermostat above the current room temperature and ensure proper flow and temperature to each zone.

With system zones on, verify that there is a normal temperature difference between the system supply and return. Typical ΔT (Delta T, or temperature differential) is 15°-25°F. Keep in mind radiant heat can take some time to bring the area up to temperature especially when embedded in concrete.

With zones running under heat demand conditions the boiler should cycle ON and then OFF when demand is satisfied.

Congratulations, you system is now operational!