ᐅ Integrated unit Stiebel Eltron LWZ 504 with central supply air system
Created on: 19 Oct 2014 20:20
D
DJCOON
Hello dear forum members,
Through a variety of professional magazines I ordered for our new build in spring 2015, I came across the air-to-water heat pump LWZ 504 from Stibel Eltron. According to Stibel, this unit offers the following:
"The compact LWZ 504 provides all the comfort expected from an energy-efficient house. The system draws energy for pleasant indoor temperatures and hot water from the outside air. Modern ventilation management ensures that the heat stays inside the building. It recovers up to 90% of the heat from the exhaust air. This allows a comfortable, healthy atmosphere to be combined with high efficiency. The demand-controlled inverter technology also ensures high efficiency. It produces exactly the amount of heat currently needed. High performance values can be achieved even at low temperatures. Energy-saving operation is supported by the modern high-efficiency heating circulation pump and excellent insulation of the hot water storage tank. For those who want to be even more independent from rising energy costs, the LWZ 504 can be operated with self-generated photovoltaic electricity using the appropriate accessories (ISG + SEE). The large, intuitive matrix display ensures that the modern technology in the award-winning design is easy to operate."
Key Features
I understand that this great system naturally comes at a price, but I would like to ask the experts among you—air-to-water heat pump owners as well as heating engineers—for advice or experience with such units. Ideally, it would be great if someone already has this exact pump installed in their basement :-)
Thank you in advance for your responses.
Best regards,
Martin
Through a variety of professional magazines I ordered for our new build in spring 2015, I came across the air-to-water heat pump LWZ 504 from Stibel Eltron. According to Stibel, this unit offers the following:
"The compact LWZ 504 provides all the comfort expected from an energy-efficient house. The system draws energy for pleasant indoor temperatures and hot water from the outside air. Modern ventilation management ensures that the heat stays inside the building. It recovers up to 90% of the heat from the exhaust air. This allows a comfortable, healthy atmosphere to be combined with high efficiency. The demand-controlled inverter technology also ensures high efficiency. It produces exactly the amount of heat currently needed. High performance values can be achieved even at low temperatures. Energy-saving operation is supported by the modern high-efficiency heating circulation pump and excellent insulation of the hot water storage tank. For those who want to be even more independent from rising energy costs, the LWZ 504 can be operated with self-generated photovoltaic electricity using the appropriate accessories (ISG + SEE). The large, intuitive matrix display ensures that the modern technology in the award-winning design is easy to operate."
Key Features
- Excellent suitability for new buildings
- Energy-saving inverter technology
- Ventilation with up to 90% heat recovery
- High domestic hot water comfort with well-insulated 235-liter (62 gallon) storage tank
- Compatible with solar systems
- Stable, sound-optimized housing construction
- Built-in high-efficiency heating circulation pump
I understand that this great system naturally comes at a price, but I would like to ask the experts among you—air-to-water heat pump owners as well as heating engineers—for advice or experience with such units. Ideally, it would be great if someone already has this exact pump installed in their basement :-)
Thank you in advance for your responses.
Best regards,
Martin
blackm88 schrieb:
At level 3 with 300 m3/h (180 CFM), you can already hear some noise near the valves.
Level 2 is 160 (daytime) and at night level 1 is 110 Definitely at 3, but it doesn’t bother in case you are having a party.
A
A. Rösner4 May 2019 00:09Thank you for your efforts.
The air exchange rates were calculated by Zehnder and set by a Stiebel Eltron technician. They are configured in our system as follows (all supply air values; the exhaust air is each time 20–30 m³/h (12–18 cfm) higher):
Level 1: 120 m³/h (70 cfm) (intended for night operation)
Level 2: 220 m³/h (130 cfm) (intended for daytime operation)
Level 3: 250 m³/h (147 cfm) (party mode)
The filters are clean. They were vacuumed again by the technician during the adjustment, and I have just checked them.
I ran the heat pump for several days only in hot water generation mode to determine whether the noise was caused by the heating or the ventilation system. Also, the upstairs was much too warm at 22–23°C (72–73°F), even though all thermostats on the upper floor were set to zero.
The hot water is set to 48°C (118°F), but with this setting the heat pump actually produces 50°C (122°F), which is required by the drinking water regulations. This was explained to me by the technician, and the heat pump confirms this as the actual hot water temperature.
The technician also explained the base load and slope, but I would need to review this again, as I am still too much of a layperson. However, I seriously doubt that anything could be optimized regarding noise generation in this respect, since these settings were also made by the technician.
At the moment, I can only imagine that the plumbing company may have installed something not entirely correctly. On the other hand, that would be the only thing the plumbing company got right at first (gallows humor).
To make it clear once again: Standing in front of the unit, it is really, really loud; it is clearly audible to loud even at the door. Inside the living rooms (supply air), I hear the ventilation system quite clearly—not loud, but distinct. It is simply an unpleasant background noise that sounds like heating/ventilation/cellar—a deep rumbling/humming... just unpleasant... and the piping carries the sound throughout the entire house, especially into the living and bedrooms. The heating noise is not (only) coming through the ventilation ducts. It is transmitted (in my estimation) somehow to the walls, water pipes, and wiring—I cannot say exactly. The noise is simply "there" in every room. I will probably just have to live with it.
Best regards
A. Rösner
The air exchange rates were calculated by Zehnder and set by a Stiebel Eltron technician. They are configured in our system as follows (all supply air values; the exhaust air is each time 20–30 m³/h (12–18 cfm) higher):
Level 1: 120 m³/h (70 cfm) (intended for night operation)
Level 2: 220 m³/h (130 cfm) (intended for daytime operation)
Level 3: 250 m³/h (147 cfm) (party mode)
The filters are clean. They were vacuumed again by the technician during the adjustment, and I have just checked them.
I ran the heat pump for several days only in hot water generation mode to determine whether the noise was caused by the heating or the ventilation system. Also, the upstairs was much too warm at 22–23°C (72–73°F), even though all thermostats on the upper floor were set to zero.
The hot water is set to 48°C (118°F), but with this setting the heat pump actually produces 50°C (122°F), which is required by the drinking water regulations. This was explained to me by the technician, and the heat pump confirms this as the actual hot water temperature.
The technician also explained the base load and slope, but I would need to review this again, as I am still too much of a layperson. However, I seriously doubt that anything could be optimized regarding noise generation in this respect, since these settings were also made by the technician.
At the moment, I can only imagine that the plumbing company may have installed something not entirely correctly. On the other hand, that would be the only thing the plumbing company got right at first (gallows humor).
To make it clear once again: Standing in front of the unit, it is really, really loud; it is clearly audible to loud even at the door. Inside the living rooms (supply air), I hear the ventilation system quite clearly—not loud, but distinct. It is simply an unpleasant background noise that sounds like heating/ventilation/cellar—a deep rumbling/humming... just unpleasant... and the piping carries the sound throughout the entire house, especially into the living and bedrooms. The heating noise is not (only) coming through the ventilation ducts. It is transmitted (in my estimation) somehow to the walls, water pipes, and wiring—I cannot say exactly. The noise is simply "there" in every room. I will probably just have to live with it.
Best regards
A. Rösner
A. Rösner schrieb:
To clarify once again: Standing in front of the unit, it is really, really loud; it’s clearly audible and quite loud even at the door. Inside the living rooms (supply air), I hear the ventilation system very clearly—not loud, but noticeable. It’s just an unpleasant background noise, it sounds like heating/ventilation/basement with a deep rumbling/humming... Does it sound like an airplane flying high in the sky? Then that’s the expected noise. For us, it’s only really audible at level 3. We operate the system at level 1, and twice a day it runs at level 2 for 2 hours.
I naively measured the noise level in front of the unit once using an iPhone app. Just the ventilation noise was 51 dB; what you mainly hear is the airflow noise near the silencers. In heating mode, it’s just under 60 dB, a low humming, not unpleasant. When heating domestic hot water, the fan speed increases, so it’s louder. 48 dB is already quite a bit. Our technician set it to 45 dB, and the legionella program runs weekly or monthly. Due to the small 230-liter (60-gallon) storage tank, I’m not too worried and have disabled that feature. Our hot water temperatures are 42.5°C (108.5°F) in the mornings and evenings, 41.5°C (106.7°F) during the day, each with a hysteresis of 2°C (4°F). That’s enough for us without losing comfort, even for a full bath. This means the flow temperature is at 45°C (113°F); every degree higher becomes more expensive.
In general, you should familiarize yourself with the “normal” settings to properly adjust the unit for your house. The system technician from SE made a solid basic setup for us, which not only kept the house warm but was also reasonably efficient. The fine-tuning has to be done yourself based on the desired room temperatures and the base point and slope settings, but this is well explained in the manual.
The SE technicians are good, but the first one set the fan start speed a bit too low. When the fans were completely off, they couldn’t restart, and the system showed errors—only by switching off a fuse could it be reset. However, this was quickly fixed. So, they aren’t perfect either, and errors can happen during installation. At temperatures below -10°C (14°F), our system went into continuous defrost mode; the issue was a hose that was 2 cm (0.8 inches) too long.
Are the corrugated filter or the blue-white filter dirty or something? Vacuuming doesn’t always help.
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