Bosch Therm 660 EF makes horrible noise in simple radiant heat system

[Joehvac25]

I wonder what ratio of glycol? Anyone who has tried to pump 100% in a system know how bad it foams. My original confusion was I thought he said he was running Dom and space but on a closer look its obviously not. With that said the water boiling sure sounds likely, I don't have the manual so I can't say for sure on the piping but fire control had that solved. I bet pump size could be a factor with the high pressure drop, or boiler pressure.

[Greg555]

The tank-less water heater is flashing to steam for lack of flow. I assume this is an "open" system, running potable water through the floor? How did you size the pump? Low-mass water heaters and boilers should be pump to rather than from followed by the expansion tank and air eliminator.

Its a closed loop

Taco 10 pump was calculated by a professional using some fancy software

[Greg555]

I wonder what ratio of glycol? Anyone who has tried to pump 100% in a system know how bad it foams. My original confusion was I thought he said he was running Dom and space but on a closer look its obviously not. With that said the water boiling sure sounds likely, I don't have the manual so I can't say for sure on the piping but fire control had that solved. I bet pump size could be a factor with the high pressure drop, or boiler pressure.

50/50

[toocoolforschool]

I would question the quality of the wiring job looks like dyi to me.

[Greg555]

Wiring is temp.

[Joehvac25]

What pressure are you running?

[toocoolforschool]

Wiring is temp.

Why?

[Greg555]

Why?

Because Im still building it and the system doesnt work yet

What if I have to move the pump? Am I gonna redo the wiring?

[Greg555]

I tried anything from 15 to 45psi

Bosch recommends 29-70psi

I wasn't sure if the higher pressure is required for the unit to turn on

Greg

[Joehvac25]

The units have a really high pressure drop through them that's why they take a special pump, if you had a pressure gauge on the outlet and inlet it would tell you more.

[Greg555]

The units have a really high pressure drop through them that's why they take a special pump, if you had a pressure gauge on the outlet and inlet it would tell you more.

I bought 2 but 1 one was only installed on the cold side

[firecontrol]

Its a closed loop

Taco 10 pump was calculated by a professional using some fancy software

Whoever it was, either didn't have the correct information to input into the "fancy software", or their professional status is in another field other than hydronics. Why? Because the capabilities of the pump you are using fall far outside of the conditions you have it installed in. That's according to the Taco software that I use to design or verify every hydronics/radiant system I build or work on.

And before you ask "then what pump should I be using", let me once again stress that supplying that information would be in direct violation of the posted rules that I agreed to when I was granted permission to post here as a pro.

[Joehvac25]

I would call some company's and find one that deals with lots of hydronics.