Hello everyone,
Our heating system consumed about 8,700 kWh of natural gas between 12/16 and 06/17, even though the house is still being renovated and unoccupied. All radiators were set to frost protection only, and no domestic hot water was used.
The system was installed in 12/15 by the previous owners and mainly consists of:
This summer, I noticed that the pipe from the solar collector (supply line) was only hot up to the pump, while the return line was almost cold. From this, I concluded that the pump was not running. At the same time, the controller showed 999°C (1,830°F) for the temperature sensor mounted at the top of the collector, which the technician said is the maximum display value indicating no plausible reading.
Testing the temperature sensor (a PT1000) was successful, so the technician concluded that the controller itself must be defective (he believed the pump was still operational).
So, a new controller was ordered, which I am still waiting for as of today, but that’s another story...
Now, with the cold season approaching, we have temporarily installed some radiators to heat the construction site a little and, most importantly, to ensure frost protection.
I was able to reduce the natural gas consumption by lowering the target temperature for domestic hot water to 10°C (50°F); however, I would say the consumption is still quite high (since Saturday, so in 4 days, about 30 m³ [1,059 ft³]... :O).
Is it possible that due to the defective controller, the 800-liter (210-gallon) water volume of the solar thermal system is being kept warm using natural gas, and usually the ESR 31, depending on whether heat is available from the roof or not, activates or deactivates a heat exchanger between the domestic hot water tank and the solar thermal water system, which in our case might currently always be open or something like that?
Maybe someone, even as a layperson, can explain how a combined stratified storage tank works or is constructed?
Many thanks in advance!
Best regards
PS: The heating technician is hard to reach; unfortunately, I have to work with him since this is obviously a warranty case. Once this issue is resolved, he definitely won’t touch our heating system again… -.-
Our heating system consumed about 8,700 kWh of natural gas between 12/16 and 06/17, even though the house is still being renovated and unoccupied. All radiators were set to frost protection only, and no domestic hot water was used.
The system was installed in 12/15 by the previous owners and mainly consists of:
- Viessmann Vitodens 200 gas condensing wall unit 19 kW
- Austria Email KWS 800 combined stratified storage tank
- Flat plate solar collectors 9.36 m² (100.8 ft²)
- ESR 31 solar controller
- Delphis solar station FV 70 (with Grundfos circulation pump on the supply side)
This summer, I noticed that the pipe from the solar collector (supply line) was only hot up to the pump, while the return line was almost cold. From this, I concluded that the pump was not running. At the same time, the controller showed 999°C (1,830°F) for the temperature sensor mounted at the top of the collector, which the technician said is the maximum display value indicating no plausible reading.
Testing the temperature sensor (a PT1000) was successful, so the technician concluded that the controller itself must be defective (he believed the pump was still operational).
So, a new controller was ordered, which I am still waiting for as of today, but that’s another story...
Now, with the cold season approaching, we have temporarily installed some radiators to heat the construction site a little and, most importantly, to ensure frost protection.
I was able to reduce the natural gas consumption by lowering the target temperature for domestic hot water to 10°C (50°F); however, I would say the consumption is still quite high (since Saturday, so in 4 days, about 30 m³ [1,059 ft³]... :O).
Is it possible that due to the defective controller, the 800-liter (210-gallon) water volume of the solar thermal system is being kept warm using natural gas, and usually the ESR 31, depending on whether heat is available from the roof or not, activates or deactivates a heat exchanger between the domestic hot water tank and the solar thermal water system, which in our case might currently always be open or something like that?
Maybe someone, even as a layperson, can explain how a combined stratified storage tank works or is constructed?
Many thanks in advance!
Best regards
PS: The heating technician is hard to reach; unfortunately, I have to work with him since this is obviously a warranty case. Once this issue is resolved, he definitely won’t touch our heating system again… -.-
H
Henny071028 Feb 2018 13:55Hello,
I’d like to share my limited knowledge here as well.
The small tube below the pump is probably a Taco setter (flow meter/regulator). Have you checked if it is set correctly or maybe even closed off?
I’d like to share my limited knowledge here as well.
The small tube below the pump is probably a Taco setter (flow meter/regulator). Have you checked if it is set correctly or maybe even closed off?
H
Henny071028 Feb 2018 14:19Maybe a silly question, but could the Taco Setter possibly be installed the wrong way around? Does it have an arrow indicating the flow direction?
wrobel schrieb:
There is an arrow molded on the side of the pump housing; you might want to double-check. I checked again (see pictures attached, unfortunately not very clear...), the arrow points upwards, which should be correct for the return flow, right?
Somehow, there seems to be a general issue with my heating system, or I don’t fully understand how it works...
We are not living there yet (still in the middle of the renovation phase), but to prevent freezing, we installed some of the old radiators on the ground floor last autumn.
Unfortunately, our heating unit does not offer an option to operate heating without heating the domestic hot water. Therefore, I lowered the target temperature for the domestic hot water to 16°C (61°F) following a recommendation from the Viessmann service line to save gas accordingly, but the domestic hot water temperature is still maintained above 50°C (122°F).
I thought this might be due to an anti-legionella function, but it is not activated.
The Viessmann service said: “Without knowing the hydraulics and the system setup on site, we cannot make any statement on this.” OK, I understand! But the heat cannot be coming from the solar thermal system in January and February, so why is the domestic hot water temperature kept so high when 16°C is set?
Also, last week the layer storage tank on top was wet... Apparently, water leaked or was drained from the pressure gauge mounted on top of the tank, but why...?!
I know I probably won’t find the cause without a professional...
Thanks for your help!
The system is now working perfectly!
A heating technician flushed, filled, and bled the system. Now heat is reaching the lower areas as well; the supply line at the pump station reached around 80°C (176°F) by noon today!
The heating technician also made a good impression, nothing like the original installer (whom I only know by phone)...
A heating technician flushed, filled, and bled the system. Now heat is reaching the lower areas as well; the supply line at the pump station reached around 80°C (176°F) by noon today!
The heating technician also made a good impression, nothing like the original installer (whom I only know by phone)...
One more quick question about how it works: The heating engineer explained to me that the control system stops activating the pump once the temperature on the roof reaches a certain level (he said it should be around 126°C (259°F)).
I understand that the water in the stratified storage tank should not boil, but why isn’t the water temperature in the tank used as the threshold instead?
For example, this afternoon the pump wasn’t running because the temperature on the roof was 140°C (284°F), even though the water in the tank was only about 53°C (127°F)...
I understand that the water in the stratified storage tank should not boil, but why isn’t the water temperature in the tank used as the threshold instead?
For example, this afternoon the pump wasn’t running because the temperature on the roof was 140°C (284°F), even though the water in the tank was only about 53°C (127°F)...
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