ᐅ Should the hydraulic balancing and individual room control be deactivated?
Created on: 6 Oct 2020 12:15
G
Golfi90
Hello everyone!
Since the heating season is slowly but surely starting again, I would like to begin adjusting our heating system (Viessmann Vitodens 200W 13 kW).
We built to KFW 55 standard with underfloor heating.
I keep reading about the hydraulic balancing. I would like to check and possibly readjust it!
Our heating technician was very committed… but not much more than that! That’s why I want to check everything myself.
How do I readjust the hydraulic balancing?
I set all room thermostats to full power (room temperature to 30°C (86°F) for example) and then check the “sight glasses” on the manifold to bring all flows to the same level, or am I misunderstanding something?
Since we have a weather-compensated system, does that affect anything?
If the balancing is correctly adjusted, what should I do next?
I would like to deactivate the ERR (electric radiator valves). How do I do that? Can I simply unplug the motors? Would they then be fully open?
If the ERR is deactivated (whatever the procedure), how do I then regulate the room temperature? Only by adjusting the flow or return water temperature of the heating system?
I would like to keep the weather-compensated control (is that possible?). Then I guess I would have to adjust the rest theoretically via the heating curve, right? How does that work?
It would be great if some experts here could offer me a bit of guidance.
Since the heating season is slowly but surely starting again, I would like to begin adjusting our heating system (Viessmann Vitodens 200W 13 kW).
We built to KFW 55 standard with underfloor heating.
I keep reading about the hydraulic balancing. I would like to check and possibly readjust it!
Our heating technician was very committed… but not much more than that! That’s why I want to check everything myself.
How do I readjust the hydraulic balancing?
I set all room thermostats to full power (room temperature to 30°C (86°F) for example) and then check the “sight glasses” on the manifold to bring all flows to the same level, or am I misunderstanding something?
Since we have a weather-compensated system, does that affect anything?
If the balancing is correctly adjusted, what should I do next?
I would like to deactivate the ERR (electric radiator valves). How do I do that? Can I simply unplug the motors? Would they then be fully open?
If the ERR is deactivated (whatever the procedure), how do I then regulate the room temperature? Only by adjusting the flow or return water temperature of the heating system?
I would like to keep the weather-compensated control (is that possible?). Then I guess I would have to adjust the rest theoretically via the heating curve, right? How does that work?
It would be great if some experts here could offer me a bit of guidance.
As far as I know, the automatic setting on 100% doesn’t work with a pump using PWM control. In that case, you need to set the pump to a constant flow rate. On paper, my circulation pump (controlled by the heating regulator) also has 100% power available, but it regulates itself based on the temperature difference and currently fluctuates between 50% and 65%.
A specific example: I give the pump 100% power for the heating system and have all balancing valves on the heating circuit distributor fully open at 100%, and the pump pushes 650 liters per hour (around 170 gallons per hour) through the system, while indicating it’s running between 50% and 65%.
When the system switches to domestic hot water mode, the pump power jumps to nearly 100%, circulating 1300 liters per hour (around 340 gallons per hour).
Regulation behavior may vary depending on the manufacturer.
A specific example: I give the pump 100% power for the heating system and have all balancing valves on the heating circuit distributor fully open at 100%, and the pump pushes 650 liters per hour (around 170 gallons per hour) through the system, while indicating it’s running between 50% and 65%.
When the system switches to domestic hot water mode, the pump power jumps to nearly 100%, circulating 1300 liters per hour (around 340 gallons per hour).
Regulation behavior may vary depending on the manufacturer.
I have a silly question. In my heating circuit distributor, I have flow meters from 0 to 3 l/min (0 to 0.8 gal/min). The same manufacturer also offers flow meters from 0.5 to 5 l/min (0.1 to 1.3 gal/min). If I replace the old one with the new one in the bathroom, would the room then have a maximum of 5 l/min (1.3 gal/min)?
Malz1902 schrieb:
If I replace the old one with the new one in the bathroom now, would the room then have a maximum of 5 l/min (1.3 gallons per minute)? What flow rate was calculated? Are you already at the limit (3 l/min (0.8 gallons per minute))? Eventually, you will reach a thermal short circuit, which will ruin the entire energy input into the underfloor heating.
lesmue79 schrieb:
As far as I know, setting a pump with PWM to automatic at 100% doesn’t really help. Instead, you need to set the pump to a constant flow rate. According to the heating controller, my circulation pump is technically available at 100% power, but it regulates itself based on the differential temperature and currently operates between 50% and 65%.
A specific example: I give the pump 100% power for the heating system and have all balancing valves on the heating circuit distributor fully open at 100%. The pump circulates 650 liters per hour (l/h) through the system while indicating an operating range around 50-65%.
When the system is in domestic hot water mode, the pump output rises to nearly 100%, circulating 1300 l/h.
The control behavior may vary depending on the manufacturer. Does this mean that you don’t actually need to set the primary circulation pump (HUP) to 100% for thermal balancing because it modulates according to PWM?
Another question: if I fully open all the top meters and then gradually lower the heating curve, is there a risk that the pump will be overloaded by the high number of open top meters and fail early? Or is there no such thing as too much flow?
It’s clear that the higher the flow, the lower the supply temperature needs to be. But can too much flow reduce the pump’s lifespan?
Just because the new thermostatic valve shows a higher value doesn’t mean the pump is pushing more flow into the heating circuit.
It depends on the pump; some can be set to a constant flow rate, others cannot.
The more thermostatic valves you have open, the less the pump has to work. Each partially open or closed thermostatic valve adds additional pressure loss that the pump must compensate for.
At a certain point, increasing the pump power no longer makes sense because the efficiency gained in compressor performance from the lower supply temperatures is offset by the additional electricity consumption of the circulation pump.
Just as an example (which doesn’t necessarily apply in every case): What would you prefer—replacing a compressor after 5 years for about €2500–3000 because it failed due to excessive cycling, or having a circulation pump fail after around 10 years for about €300, replaced by the heating technician for about €200?
annab377 schrieb:
Does this mean that you don’t have to set the main shut-off valve (HUP) to 100% for hydraulic balancing, since it is also “modulated” according to PWM?
Another question: if I open all thermostatic valves fully and then gradually lower the heating curve, isn’t there a risk that the pump will be overloaded by the many open valves and fail prematurely? Or is there no such thing as too much flow?
Because the more flow, the lower the supply temperature needs to be, that’s clear. But is there such a thing as too much flow (at the expense of the HUP’s service life)?
It depends on the pump; some can be set to a constant flow rate, others cannot.
The more thermostatic valves you have open, the less the pump has to work. Each partially open or closed thermostatic valve adds additional pressure loss that the pump must compensate for.
At a certain point, increasing the pump power no longer makes sense because the efficiency gained in compressor performance from the lower supply temperatures is offset by the additional electricity consumption of the circulation pump.
Just as an example (which doesn’t necessarily apply in every case): What would you prefer—replacing a compressor after 5 years for about €2500–3000 because it failed due to excessive cycling, or having a circulation pump fail after around 10 years for about €300, replaced by the heating technician for about €200?