How To - Install the Combi Boiler Adaptor

Hugh the Tech Ducky

How to Install the Combi Boiler Adaptor




Written instruction for how to Install the State Proline XE Combi Boiler Adaptor

(2 wrenches needed, about 5 minutes)

parts of the combi boiler adaptor for the hug hydronics in-floor heating system 

  1. In place of the over-pressure valve, use the wrenches and plumbing tape/compound to put on the 3/4 “ to ¼” stainless steel adapter with nylon fitting.use the pipe wrench to tighten the adapter and the other wrench to hold the pipe so it doesn't bend or twist
  2. Insert the probe and hand tighten.hand tighten the nylon partscombi boilers connection with hug hydronics easy in floor heating adaptor
  3.  Remove the black hole plug from the top of the Combi Boiler by pinching it from underneath until it pops plug from top of the combi boilerhow the probe fits on the top side of the combi boilers
  4. Slide the power connector through this hole.slide the power connector through hole
  5. Remove the low water cut off (LWCO jumper plug) from the combi control board.
  6. Replace it with our Power Connector .steps 4 and 5
  7. If your combi boiler has a pressure sensor: Unplug the wires from the pressure sensor and plug the jumper wire to connect them.unlug the two wires from the pressure sensor and use the jumper wire to connect these wires

  8. On the HUG Tank, loosen the thumb screws on the right back side of the control board. Wiggle the screw slots on the Control Box under install the control box, loosen the thumb screws holding the control board on, slide the  holes in the side of the black box under it, and tighten
  9. On the HUG tank, remove a plug from an empty hose hole and replace with the adaptor’s water hose.put the water hose through a hose hole in the hug hydronics in floor heating tank

  10. Route the Purge Connector through a hole right under the control board, and plug it into the “purge” pins at the top of the pump section that is feeding the combi boiler (usually pump #10).route the purge connector  to the purge pins of pump 10

  11. Fasten the adaptor cable to the wall using wall clamps.

  12. When you turn on the combi boiler, the LED on the Control Box should glow green (if there is water). It glows red when it senses the need for water and it is purging.

 the control box light will glow green unless it is filling

wiring diagram for the combi boiler adaptor and the rib and power supply

Initial fill of boiler:

Once the Combi Boiler Adaptor is installed,

Make sure the HUG Hydronics tank is full of water (or antifreeze).

Make sure power is on for the tank and pumps

Turn on the power to the boiler.

The light on the Combi Boiler Adaptor will be red, indicating that water is low.

Pump 10 should come on and the boiler should start filling with water.

You should hear air bubbles coming out of the little adaptor hose

Keep adding water (or antifreeze) to the tank as needed.

If filling the tank takes longer than 30 seconds, the flow may start cycling on and off every 30 seconds or so. This is normal.

When the boiler is full, the system will automatically stop filling and the red light on the Combi Boiler Adaptor will turn green, indicating that the boiler is ready to operate.


Normal Operation:

When all is well, the Combi Boiler Adapter light will be green, indicating that water is all the way to the top of the boiler.


If enough air builds up in the boiler so that water no longer touches the probe, the light will turn orange and pump 10 will come on, adding water to the boiler and purging the air. Normally this takes less than a second.