Danfoss problems again

[richo 4]

After a few month of good work my Danfoss valves started to have problems with HC2.

Three of them are not beeing updated - just see the message "Waiting for wakeup". Didn't change anything in that last few month except that have upgraded to 3.575 but few weeks ago. Batteries are almost full.

Have benn playing with valve, unmounted, mounted batteries out and in... Reconfiguration doesn't help. have upgraded today to 3.580 but problems are the same.

It's interesting that I have removed battery from one of the Danfoss 2 weeks ago and HC didn't notice that !? It still shows the device as active with battery !?

Any ideas or similar issues with the latest version of software?

Looks like communnication problem - when moved close to HC it worked - back in it's place and no comm. It worked for almost a year and now stopped

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[hvb83 1]

I had problems with the Danfoss units and cheaper batteries. My previous controller sometimes ate through the batteries within 2 days, so with Duracells that would become a very expensive luxury.

My units also indicated that they were 3/4 full, but even so I still got problems like the Danfoss sometimes resetting to 21 degrees (the standard setpoint when the batteries have been reinstalled). Also in regard to getting it installed, it often provided problems. These problems showed themselves on all units. Now that I have A-brand batteries installed again, my problems with all Danfoss units have vanished. To add to the confusion, the old batteries are still functioning perfectly fine in my wii-fit board, so they're not really empty...

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Try it, in my experience, at least with cheap batteries, the battery indication is unreliable and no indication of the proper functioning of the battery inside the Danfoss...

[richo 4]

hvb83,

I have AAA Brand batteries ENERGIZER ULTIMATE LITHIUM

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/emoticons/default_icon_wink.gif" alt=";-)" /> - most of them at over 90% for 3 month. Anyway thanks for the response and advise.

Had to reconfigure all Danfosses, unmount-mount few times etc and looks like it started to work again...

PS - to Fibaro guys

Here is interesting change in Danfoss settings from heating panel - I didn't know that Danfoss can acceppt negative temp setting

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[ivan.ruban 3]

I believe that the devices like Danfoss LC must be DC operated! I played with one Danfoss LC and then also read a lot of discussions about the need to place Danfoss LC close to HC2, and also a short life of its battery. I finally decided to use Danfoss 24v valves (has open/close state).

The order will come in 1-2 weeks. I plan to use them as linked devices in heating panel in HC2. This solution should be more reliable than z-wave Danfoss LC. We'll see how it will work in reality.

[Quikdav 15]

I wait for your feedback with these kinds of valves because I'm a little disappointed with these valves..

Thanks

David

[richo 4]

I use both type of Danfoss valves.

With Danfoss LC the good thing is that they will work even when HC is down. Using just Danfoss 24V/220V the risk is that your heating system is down if something is wrong with HC.

[ivan.ruban 3]

I wait for your feedback with these kinds of valves because I'm a little disappointed with these valves..

I want to share finally the result of experience. I have recently installed a pack of following devices in 2 rooms:

- Fibaro Switch + 24v Danfoss electrical valve

- Fibaro Universal sensor + DS18B20

- Linked heating device (Switch and DS18B20) and heating panel

Everything works as a charm. I always know in which mode my radiator is right now (it is easy: on or off), I always know the temperature. I also have the same functionality in my IPhone for radiator as before - I can set a temporary temperature for defined number of hours.

So to summurize:

1) The device work is much more transparent now

2) No z-wave connection issues at all

3) No battery issues (there is no batteries

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There are options of 220v Danfoss valve by the way. I bought 24v because of safety (not so fun to get 220v on radiators by mistake

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/emoticons/default_icon_eek.gif" alt=":shock:" />). But it shoud be even more easier with installation of 220v - no transformer is needed then!

[Dalle1985 15]

Using an on/off valve to control radiators is a very uneconomical way of operating. The optimal way of running a radiator is for it to be as hot as possible on the inlet, but as close to room temperature as possible on the outlet. This means that you are extracting the absolute most energy from your radiator. The way to do this is to have a constant flow through the radiator. When you open and close the radiator in sequence, you will only do this, if you only just displace the amount of water in the radiator, close the valve and wait for the radiator to cool down just enough to keep the room temperature up.

If you have a simple on off regulator, being controlled by an external controller, you will be pouring hot water through your system with only little energy yield. Even if you have a circul ting system, the fluid heater will transfer far less heat to the water and therefore loose a lot of efficiency.

A thermostat will open the valve a certain amount based on an error (the difference between the set temperature and the actual temperature) so the larger the difference, the more it will open or close. At some point, you reach equilibrium and the thermostat should hold a certain opening (fixed flow). This is called a P-regulator.

The danfoss LC thermostats go a step further and also regulate based on the time that there has been a difference between desired temp and actual temperature. So it will open more if it senses that the temperature isn't changing as it should. This is called a PI-regulator.

An on off controller does none of this. It either allows or stops flow and is therefore very inefficient as it will use the same watt effect to change the room temperature 1 degree as it will 10 degrees. So unless the room is very small or the thermometer is very close to the thermostat, my guess is that room temperature will be fluctuating.

Compared to a standard (non intelligent) thermostat, an on off regulator will use at least 30% extra energy. Compared to a clever thermostat - such as the Danfoss LC the difference is easily 40-50%. So if energy is dirt cheap, no problem. But here in Denmark, energy is quite expensive, so it could easily cost an additional 1000-1500€ pr year to have on off control.

If you have in floor heating though, the story is somewhat different... But then you can't use the danfoss LCs anyway.

[hvb83 1]

Dalle is right, with on/off control your heating will be very inefficient. In essence you want the flow of your water the be as low as possible, while still being able to get all radiators in the house heated. As a rule of thumb it is said that a delta-T of 20 degrees between your inlet and your outlet of each radiator is ideal.

Add to that, a High-Efficiency boiler will use the energy from condensation between the exhaust fumes and the water, but this is done by heating the water coming back from your radiators. If that temperature is above 55 degrees, the "High-Efficiency" effect will be gone; in essence it will be conventional boiler then. This could result in a 15% lower efficiency.

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You could partially solve this issue by using a separate valve on each radiator and tuning the flow of the system for all radiators with those valves. But that will still present the problem that the system will be out of balance if you only run one or two radiators; your efficiency will be down the drain once again.

In most cases, the LC-valve will remain to be the best option. Although I had some problems with them at first, they soon disappeared. If run with proper batteries, I myself haven't found anything really wrong with them right now.

[Lauri 6]

Hi,

can you show what kind of batteries do you use with danfoss?

[hvb83 1]

In the past I had very cheap Philips batteries (since with Zipabox the panic mode could eat through a set of expensive batteries over night). With HC2, even though the battery indicator still showed 30% battery, it would behave strange. Sometimes resetting to 21 degrees and stuff like that. Also I had some initial problems with getting them to keep the Z-wave connection.

Right now I'm running them with Duracells and Panasonics for a couple of months, no more issues what so ever. Perhaps the connection issues were due to the valves having to find their neighbour nodes or something, but the 21 degrees issue was definitely due to the batteries.

[ivan.ruban 3]

Compared to a standard (non intelligent) thermostat, an on off regulator will use at least 30% extra energy. Compared to a clever thermostat - such as the Danfoss LC the difference is easily 40-50%. So if energy is dirt cheap, no problem. But here in Denmark, energy is quite expensive, so it could easily cost an additional 1000-1500€ pr year to have on off control.

Hmm, that sounds impressive. Thanks Dalle1985 and hvb83 for your considerations. In my case the energy is actually cheap - I live in apartment and get a hot water for a fixed monthly price. So I spend the energy only for powering valves in my case. Every valve consumes 2W when it is opened - it is really nothing. The average price of 1kwH is 0.5 SEK (0.056 eur) in Sweden.

In case of the house with the bolier heating system, it is of course a different story. But is it really 30-50% increase of energy consumption? It sounds much.

What forced me actually to try electrical valves is a very good topic about Fibaro experience here:

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And this advice:

4. If you plan to use Danfoss valves make sure that all of them are in the reach of HC - otherwise buy some electrical valves and control them with switches.

And that is what I also read in other topics. There were many people complained about communciaton issues in Danfoss, when they are not in reach of HC2 controller.

Right now I'm running them with Duracells and Panasonics for a couple of months, no more issues what so ever. Perhaps the connection issues were due to the valves having to find their neighbour nodes or something, but the 21 degrees issue was definitely due to the batteries.

It seems like the quality of batteries depends directly on z-wave connection issues. Good if it can be fixed just with better batteries. But how far from HC2 are your valves located?

[Dalle1985 15]

The difference really is quite huge. It should be pretty straight forward to create a small simulation to show the difference.

I remember as a child we lived in an old farm with manual valves, when these were changed out to thermostats, the oil fired boiler consumption fell by 25%... And then you have to remember that the hot water consumption was the same, so the heating gain was even bigger.

But if you have a fixed cost heating scheme, then you need not worry as much about it.

The ideal setup would be to have a servo actuated regulating valve on each radiator which links into a central controller with a PID control sceheme which takes into account the difference between setpoint and actual temp. The time that the difference has been there and the slope of the change. This is a very common controller for industrial application. But it should also help improve on efficiency in home heating.

[ivan.ruban 3]

... central controller with a PID control sceheme which takes into account the difference between setpoint and actual temp. The time that the difference has been there and the slope of the change.

I guess Danfoss has already the smart heating controllers for multiple room + boiler? The problem here as I may guess they are not supported in HC2.

There are also enthusiasts (

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) that are trying to do the similar smart heating solution. They plan to use HC2 as a controller and implement the logic in LUA. They try to take into consideration different factors that influences to heating. Good luck to the team!

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What I cannot understand - why Danfoss LC does not have a micro USB port for DC 5V powering. It could solve a lot of issues with powering the device (and connection issues as a consequence). I also have one cheap non-zwave electronic valve that is not as smart as Danfoss but works fine and has micro-USB port.

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[hvb83 1]

Trust me, in commercial buildings proper tuning and commissioning of the M-installations is becoming increasingly popular. Building owners and tenants are becoming more aware of the costs savings to be had there. That's for a reason; it will cost between 20 to 30% if the tuning is out of balance. And for high-efficiency gas fired boilers or heat pumps the proper tuning is even more important, because otherwise you may increase the inefficiency even further (up to the 40-50% already mentioned).

I understand now that in your situation this is not such a critical item, but in general, I would advice against using simple "on/off-valves" for controlling the heating.

You could attach it to a 3v adapter. That way it won't become a node device of course, but in any case you could then set the interval to a very short amount of time, to increase the response to your commands.

[ivan.ruban 3]

You could attach it to a 3v adapter

Is there any DC port on Danfoss LC device? What I mean it should have a standard port for attaching the adapter. It does not matter if it has for example 2.1 mm or micro USB port. Micro USB is nevertheless preferrable since it is a more spread standard. Or it should have screw terminals - then it works also fine. Otherwise (when there is no port/screw terminals) it is more a less a hacking IMHO.

I prefer to have all my devices DC powered and don't care about batteries. And I do the hacking all the time - I solder cables from plug-in adapter to "+" and "-" battery terminals. That is not the right way to do. But that's what I did for instance with Everspring SP103 and fibaro door sensor. And I was really dissapointed that new Fibaro multi sensor has no DC power terminals/port. Aeon with micro USB is much better in this case.

[hvb83 1]

Indeed you'll have to solder the wires to the battery terminals. I doubt it will bring the stability advantages that the Aeon sensor shows when doing usb-power, since that device actually runs in a different mode once you connect it to usb. Danfoss LC won't do anything differently...

But in general I agree with your point of view; DC power is preferred over batteries at all times. But for the door sensors this is kinda hard. Must say that I have the Fibaro door sensors on for quite some time now, some of them with a temperature sensor in it which consumes quite some more energy, but that's no problem. I think they should last 1,5 years easily, the ones without temperature probably longer.