J
JSlippy
We’ve had a UFH system installed as part of our home renovation which is run alongside our existing radiators. Some of it is in rooms with LVT flooring which means we’ve got to be careful with water temperature (floor temp limits are set, but can easily overshoot if water is too hot).
Our problem is that sometimes the mixing valve shuts the flow down completely even when the UFH pipes are cold. Today our lounge wasn’t warming up so I checked the system. The pump was running but all flow meters were at zero. The temperature going into the manifold was about 30 degrees, but the return temp from the manifold was about 40.
Presumably the mixing valve closed completely when the return temperature reached 40 degrees. But because the valve is closed, it can’t detect when the water in the UFH pipes falls (for example if a different room calls for heat).
I turned the mixing valve setting from 4 to 6, which instantly sent flow through the system and the return temperature dropped like a stone! I was able to drop the valve back to 4 and it worked as normal.
Surely this isn’t the way the system is supposed to work. I understood that the mixing valve was supposed to blend water from the boiler with the manifold return, but keep water flowing through the UFH pipes the whole time. That clearly isn’t happening here, does that indicate a problem with the way the system is set up?
The pump is a Grundfos UPS3, mixing valve is ESB VTG141. We can get the installers out but there's no chance I'll be able to replicate the problem for when they're here! If anybody has any tips on whether this is expected behaviour or what should really be happening, it would be appreciated!
Our problem is that sometimes the mixing valve shuts the flow down completely even when the UFH pipes are cold. Today our lounge wasn’t warming up so I checked the system. The pump was running but all flow meters were at zero. The temperature going into the manifold was about 30 degrees, but the return temp from the manifold was about 40.
Presumably the mixing valve closed completely when the return temperature reached 40 degrees. But because the valve is closed, it can’t detect when the water in the UFH pipes falls (for example if a different room calls for heat).
I turned the mixing valve setting from 4 to 6, which instantly sent flow through the system and the return temperature dropped like a stone! I was able to drop the valve back to 4 and it worked as normal.
Surely this isn’t the way the system is supposed to work. I understood that the mixing valve was supposed to blend water from the boiler with the manifold return, but keep water flowing through the UFH pipes the whole time. That clearly isn’t happening here, does that indicate a problem with the way the system is set up?
The pump is a Grundfos UPS3, mixing valve is ESB VTG141. We can get the installers out but there's no chance I'll be able to replicate the problem for when they're here! If anybody has any tips on whether this is expected behaviour or what should really be happening, it would be appreciated!
