We have been using our Viessmann heat pump for a few weeks now. So far, it only needed to provide cooling and hot water, but now that the nights and days are getting colder, we noticed that the ground loop pipe has developed a thick layer of ice, especially in areas where there is little or no insulation on the pipe. During the day, the ice melts and drips, making the floor wet.
I thought this was due to insufficient insulation, and that fully and properly insulating the pipes should solve the problem. However, I recently read that while insulation may help prevent icing, it doesn’t address the root cause, and that this kind of ice buildup isn’t normal. Does anyone have experience with this?
I thought this was due to insufficient insulation, and that fully and properly insulating the pipes should solve the problem. However, I recently read that while insulation may help prevent icing, it doesn’t address the root cause, and that this kind of ice buildup isn’t normal. Does anyone have experience with this?
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neo-sciliar29 Sep 2020 18:30Which brine-to-water heat pump do you have? What is its kW capacity?
It seems that the brine and heat pump don’t quite match. Although with 210 meters (about 690 feet), you should be able to connect a decent load (in poor areas, 50 W per meter would result in a 10 kW load). Maybe there is air in the system due to flushing? Incorrect refrigerant?
It seems that the brine and heat pump don’t quite match. Although with 210 meters (about 690 feet), you should be able to connect a decent load (in poor areas, 50 W per meter would result in a 10 kW load). Maybe there is air in the system due to flushing? Incorrect refrigerant?
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Stadtvilla1929 Sep 2020 18:47Have I mentioned before that we have a Viessmann Vitocal 222G with an NC Box and 7.54 kW output? Originally, the offer included a 333G model with 10.5 kW, but after calculations, this is what we ended up with... I’m not sure if this is correct, and we are still somewhat in disagreement with the company about it...
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neo-sciliar29 Sep 2020 18:54Since the brine pipe is freezing, it means it is being used—just with too little output, otherwise it wouldn’t be below zero degrees (our ground collector is now about +10°C (50°F) at the end of a cycle). Take a look at how long your compressor runs continuously and how often it cycles on. I’m not familiar with Viessmann; does it have a data logger, and can you provide the data from the past few weeks?
Hmm, series connection. Quite unusual in my opinion. It has disadvantages in terms of pressure loss, meaning higher pump energy consumption, and maybe the pump is too weak? Bleeding the system is also much more difficult than with a parallel connection.
There are specialized forums for this kind of issue. However, I would recommend getting the system installer involved, preferably with the manufacturer's service team directly.
There are specialized forums for this kind of issue. However, I would recommend getting the system installer involved, preferably with the manufacturer's service team directly.
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JansEigenheim29 Sep 2020 20:27It is most likely connected according to the Tichelmann principle; apart from an individual connection to a manifold, anything else would be quite unusual. A heat pump with 7–8 kW will be sufficient for your house, especially when considering solar and other gains. And with heat pumps, oversized = really bad (especially with a fixed-speed model like yours).
Since the temperature difference in the ground loop according to your data is only 2 degrees Celsius (3.6°F), there has to be some flow; otherwise, it would be much higher, and your pump wouldn’t reach 15 minutes of runtime but would instead shut down quickly with an error. It is likely that one or two of the probes are not properly vented, causing the system to essentially run on just one loop. This can happen in Tichelmann systems and is generally more complicated to fix than if the loops could be individually shut off for venting. Because your unit only operates at full power, with such an "artificially" undersized source, temperatures can drop quickly.
Could you share an overall picture of the system out of curiosity? Is there a buffer tank? What does the pressure in the ground loop indicate? Is there an air vent at the highest point?
If you’re interested in optimizing your system, you should introduce yourself in the forum. But don’t be discouraged if they initially criticize your system—they are usually willing to help you get the best performance out of it.
Since the temperature difference in the ground loop according to your data is only 2 degrees Celsius (3.6°F), there has to be some flow; otherwise, it would be much higher, and your pump wouldn’t reach 15 minutes of runtime but would instead shut down quickly with an error. It is likely that one or two of the probes are not properly vented, causing the system to essentially run on just one loop. This can happen in Tichelmann systems and is generally more complicated to fix than if the loops could be individually shut off for venting. Because your unit only operates at full power, with such an "artificially" undersized source, temperatures can drop quickly.
Could you share an overall picture of the system out of curiosity? Is there a buffer tank? What does the pressure in the ground loop indicate? Is there an air vent at the highest point?
If you’re interested in optimizing your system, you should introduce yourself in the forum. But don’t be discouraged if they initially criticize your system—they are usually willing to help you get the best performance out of it.
J
JansEigenheim29 Sep 2020 20:54Vitocal 222G vs Vitocal 333G is ultimately not a question of maximum capacity. Both models offer options around 10 kW or 7–8 kW. One modulates, while the other is fixed speed.
There are actually few reasons to choose a fixed speed over a modulating unit, perhaps only the price. I’m not sure what the difference was for you.
There are actually few reasons to choose a fixed speed over a modulating unit, perhaps only the price. I’m not sure what the difference was for you.
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