Recomendation about floor heating valves

[Giovani]

I plan to control underfloor heating with simple electric valves which provides on/off functionality. Since there are two type (normally open or normally closed) which type you recommend according to experience?

[Gast]

I think the best is NO, because if you have any problems and your home is without energy, is better the valves open, and all underfloor circuits are communicate, in the other case, if the water inside the pipes is hot, you could have underpressure inside the pipes when the water cold down.

I don't know if I explain good, sorry but my english maybe is not better enough.

[Giovani]

@mrp0t4t0 thanks for feedback - my approach would be similar - if there is no power valves shall be opened but I wanted to get feedback from somebody who already implemented controlling underfloor heating with such "ON/OFF regulators".

[Jan W.]

There were some discussions around this topic in the German part of the forum, maybe Google translator is able to translate it properly: https://www.loxforum.com/forum/hardw...4411#post94411

I have the NC valves, but only because they were the "default" here in Germany. If I would get another choice, then I would choose the NO (normally open) type, because these valves consume power when operating in the other state (here closed). In a modern house with good insulation, proper hydraulic adjustment the valves would be open most of the time when used with an underfloor heating. Therefore the total power consumption would be less with with NO type valves. There are different types (230V AC vs. 24V DC) available and different power consumption depending on the model / vendor (good ones have only 1W, other 2W). For underfloor heating the on/off type valves are sufficient and much cheaper than the steady ones and Loxone Air or Tree.

Another argument towards the NO valves: if the MS (not the electricity to control the heating itself) is down, e.g. due to an SD-card error, then it would be much better to have it warm in all rooms than cold ;-)

Here is another thread around this topic: https://www.loxforum.com/forum/hardw...gen#post171354 (also German)

[Gast]

It would have to be NC. This makes more sense.

The argument about a power failure does not make sense as without power, nothing else would work anyway (boiler, pump, controls, etc.).

[Jan W.]

As I said before: there are some reasons why the MS=Loxone Miniserver can be down. If there is a full power outage a modern heating does not work anyway. I don't see an advantage with NC over NO.

[Christian Fenzl]

NC is easier to implement (program) within Loxone Config.
NO may save some energy, if you program it to power off in the non-heating seasons.

[Jan W.]

With NO you could add simply a NOT circuit in Loxone config, so it's not that much more complicated ;-) NO could even save some energy during the heating season, if you have underfloor heating, a good insulation and hydraulic balance, so the valves are open at most times and don't consume power.

[Gast]

NO just does not make any sense. The valves would be closed most of the time in a normal well insulated home. You would spend more energy to keep them closed.

NC is the most sensible option.

Loxone will handle either - makes no difference.

Best speak to a professional plumber about your requirement.

[Christian Fenzl]

That’s not correct. In a good insulated home with correct heating settings, valves should be open the most time.

[Labmaster]

NO just does not make any sense. The valves would be closed most of the time in a normal well insulated home. ....

Sorry, but this is wrong !!!

In a well designed floor heating system ( insulation, heating system, hydraulic balance ...) all single floor heating valves should be open most of the time, where the heating system itself is controlling the global heat energy, that goes thru the whole system, at once.

If you don't have a active cooling option then NO valves actors normaly are by far the better solution.
If you have a active cooling option for your "floor heating system", then some calculations have to be done to get the rigth decition if NO or NC valve would fit better.

BTW:
and again Sorry, but most "professional plumbers" have no clue about saving electrical energy and all the side effects that not part of their buissnesses ;-)


My prefered valve actor is the Moehlenhoff Alpha 5 230V AC "Normally Opened".
This Valve is NO and IF closed, consumes 1W only.
Adapters are available for most valves out there. ( https://www.selfio.de/fileuploader/d...1447056668.pdf )