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Radiant heating with Buderus 115/5 - Riello 40 F5 , (2) XPB mixing blocks and Wisrbo manifolds.

tyracz Member Posts: 10

I have searched this forum back and forth and I cannot find proper answer for my issue/problem.

I just purchased a house after it being foreclosed for 2.5 years.

It has radiant floor heat all over the place ( even garage ).

Boiler - Buderus Logano G115/5 with Riello 40 F5 burner.

(2) XPB mixing blocks for each floor

(3rd picture - grey XPB ) - 1st floor - 1/2 PEX leaving Wirsbo manifold - it is working good and keeps the space at 72 F.

(4th picture - green XPB) - 2nd floor - 3/4 PEX leaving XPB and going to Wirsbo manifold that supplies water to 2 upstairs bedrooms, laundry room, bathroom and hallway

(4th picture - green XPB) - second 3/4 PEX leaves XPB supplies water only to master bedroom.

Supply line from boiler has TACO circulating pump.

2nd floor cannot get above 68F, this morning at 5:30 AM it was 66 F.

Both RMB-1 controller settings - i have 1 outdoor sensor for each RMB-1 outside :

Mixing target temp - 135 F
Outdoor Design Temp - 10
Mixing Design Temp - 130 F
Mixing Max Temp - 140 F
Mixing Min Temp - 120 F
WWSD - 72 F

As i said before , 1st floor is at optimal 72 F temp, i have daughter at 19 months and i need to rise upstairs temp. Boiler is running very often and does not seem like it can meet my settings because it runs for 15 min every 15 min...

First thing i did to this system was opening boiler and cleaning the boiler from soot. It was packed with stuff so i have vacuum everything, removed baffles, used brush to clean entire inside and placed baffles back at its original positions. Then I have replaced flue piping, it had holes and corroded, I used 24 gauge 6" pipe.

My chimney was cleaned and proper ventilation was confirmed.

House was winterized so i turned the water on and I purged air from entire system by closing each manifold line, removing one by one return PEX and draining it to the bucket until line was full of water. This step was performed on each of 3 manifolds (basement one, one serving master bedroom and one serving 2 bedrooms, hallway, laundry room and bathroom ).

After that I have turned boiler ON and let system to heat up.

I had boiler temp on RMB-1 set to 180 F but it cause boiler to run for 2 days straight using A LOT of oil...

I figured out that that is too high so i dropped it to 150F.

From that moment i started researching online and this forum to find tips and tricks to make this system work. I have couple flow meters and balancing valves on order to replace 2 that i think may not be working right - that is for 1st FLOOR ONLY.

Please let me know if there is any chance i can get this fixed myself, need to change settings on RMBs.


  • STEVEusaPA
    STEVEusaPA Member Posts: 5,695
    There's too much going on to guess, although you do have some water leaks.
    It's going to require indepth troubleshooting from a competent tech.
    1. Enough water in the system.
    2. Properly purged of air.
    3. Are the components actually working.
    Then go over the settings...
    Then go over the design...
    1. Amount of BTU's needed per zone, tube size, length of loops, etc (You'll probably have to do some reverse engineering and guessing).
    2. Proper sized circulators and flow rates.

    You shouldn't have had to remove pex lines to purge. Also if that pex doesn't have an oxygen barrier, your circs and mixing blocks may be full of crud.
  • tyracz
    tyracz Member Posts: 10
    edited January 2018
    I opened each mixing block and checked cartridges and pumps, all 4 pumps are working when in manual mode. Also blocks are clean.

    Water leaks on manifold - grey one - are from 1 flow meter, it has cracked glass, i have 4 on order to change it and have few spares.

    Once all leaks will be taken care of i will clean manifolds so i have idea if there are any future leaks.