Hello, for the first 2 to 3 seconds the pressure in our domestic hot water line is very high and then stabilizes. What could be the cause? We have an air-to-water heat pump. I have attached some pictures showing individual valves. Could it be related to these? I am concerned that this issue might negatively affect the heating system. The pressure only builds up again afterwards. If I use hot water again shortly after, the pressure is normal. We do not have continuous circulation.
I assume the pressure doesn’t just increase again “over time,” but only when the heating system is actively producing hot water?
Basically, this is somewhat normal. When water is heated, it expands. And if all the hot water taps are closed, the pressure will rise.
However, it’s usually only a small increase because there is typically a valve on the heating system that releases the excess pressure.
Maybe that valve is missing or not set correctly – I would just have a professional plumber check it.
Basically, this is somewhat normal. When water is heated, it expands. And if all the hot water taps are closed, the pressure will rise.
However, it’s usually only a small increase because there is typically a valve on the heating system that releases the excess pressure.
Maybe that valve is missing or not set correctly – I would just have a professional plumber check it.
It’s the same here.
When the heating system heats water, the pressure rises. The same happens when the solar system is running.
The pressure sometimes increases similarly to your case, but the volume is minimal. If you open any faucet and let a few drops out, the pressure on the water pressure gauge returns to normal.
So, there is pressure, but no volume.
When the heating system heats water, the pressure rises. The same happens when the solar system is running.
The pressure sometimes increases similarly to your case, but the volume is minimal. If you open any faucet and let a few drops out, the pressure on the water pressure gauge returns to normal.
So, there is pressure, but no volume.
What was the outcome here, actually?
I’ve made the same observations. After heating the hot water, the pressure rises briefly when you turn on the hot water. Also, I seem to be losing pressure in the underfloor heating system somehow.
I’ve considered two things. It could be related to switching between hot water and underfloor heating, or it might be the safety valve. There is always some moisture in the drain hose, and I occasionally hear dripping into our pump sump.
I’ve made the same observations. After heating the hot water, the pressure rises briefly when you turn on the hot water. Also, I seem to be losing pressure in the underfloor heating system somehow.
I’ve considered two things. It could be related to switching between hot water and underfloor heating, or it might be the safety valve. There is always some moisture in the drain hose, and I occasionally hear dripping into our pump sump.
Okay, I reviewed the installation and the hydraulic diagram from Vaillant again. The specified expansion vessel (MAG) for hot water is not installed. As a result, everything flows out smoothly through the valve during hot water preparation.
I will take a closer look at it tomorrow and will make a video of the pressure gauge on the hydraulic station after hot water preparation to see if I notice any fluctuation when switching.
I will take a closer look at it tomorrow and will make a video of the pressure gauge on the hydraulic station after hot water preparation to see if I notice any fluctuation when switching.
Our situation remains unchanged. Because of our photovoltaic system, I have set the water to only be heated around midday. This has already resulted in the issue occurring at most once a day.
Today, I noticed that the pressure on the safety group is very low. Isn’t that actually contradictory?
Which pressure gauge do you want to check?
Today, I noticed that the pressure on the safety group is very low. Isn’t that actually contradictory?
Which pressure gauge do you want to check?
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