I need some experienced help here: I have a Vaillant VHR 35 C that has been behaving erratically in the last few months: after the hot water is left running for some time form the tap, the boiler goes in an S54 state and the water gets cold. I then have to reset it and hot water comes again. Sometimes it stops again after a few minutes, if hot water is left running. I have discovered reading this forum that this is normally due to a too-large water temp difference (before and after the burner ??).
As a matter of fact, lately I had noticed that the tap water seems much hotter than it used to be in the same tap position.
Yesterday it also did it with the heating, showing an F23 message.
I had been looking for info in this forum when the problem first manifested itself and I was now waiting to see whether one part (pump, three-way valve …) would eventually fail, but it has not happened yet and we are getting in the middle of a cold week, so I need to act.
When the heating stopped yesterday, I checked and noticed the following.
The pump appeared to be alive, even though it was making a funny tic-tic-tic noise.
The temperature in the boiler had gone down to 29 deg; after resetting it, the flame went on (not immediately) and the boiler went into full burst, bringing the temp to 45-48 in 10-20 seconds, after which the flame intensity went down. The thermostat was on 24 and the room temperature was 19, so I would have expected the boiler to keep burning at the max level for a while, but this did not happen.
The radiators eventually warmed up, though.
Both pipes at the entry and exit of the circulation pump were cold, the only warm pipe was the heating outlet, but it was roughly at 40deg, as I could touch the pipe without burning my hand. This morning the system worked fine – luckily !
I have already called a technician, but he will opnly be able to come in a few days. Besides, when I had called him a few months ago, first he wanted to know the error code, that I had not yet written down, but when I told him that it was S54, he simply told me that he did not know what the code meant and that he had to ask Vaillant, which did not give me a very warm feeling !
Any experienced advice will be very welcome !
Incidentally, I was looking for the price of the pump (Vaillant VP5ZE PWM S2, P/N 59866536, Grundfos 160967), but I could not find it anywhere on the web, which is surprising. Has it been replaced by a different model ?
Thank you
Alberto
I have uploaded pics of the boiler on my album but I am not sure whether they are visible to everybody.
As a matter of fact, lately I had noticed that the tap water seems much hotter than it used to be in the same tap position.
Yesterday it also did it with the heating, showing an F23 message.
I had been looking for info in this forum when the problem first manifested itself and I was now waiting to see whether one part (pump, three-way valve …) would eventually fail, but it has not happened yet and we are getting in the middle of a cold week, so I need to act.
When the heating stopped yesterday, I checked and noticed the following.
The pump appeared to be alive, even though it was making a funny tic-tic-tic noise.
The temperature in the boiler had gone down to 29 deg; after resetting it, the flame went on (not immediately) and the boiler went into full burst, bringing the temp to 45-48 in 10-20 seconds, after which the flame intensity went down. The thermostat was on 24 and the room temperature was 19, so I would have expected the boiler to keep burning at the max level for a while, but this did not happen.
The radiators eventually warmed up, though.
Both pipes at the entry and exit of the circulation pump were cold, the only warm pipe was the heating outlet, but it was roughly at 40deg, as I could touch the pipe without burning my hand. This morning the system worked fine – luckily !
I have already called a technician, but he will opnly be able to come in a few days. Besides, when I had called him a few months ago, first he wanted to know the error code, that I had not yet written down, but when I told him that it was S54, he simply told me that he did not know what the code meant and that he had to ask Vaillant, which did not give me a very warm feeling !
Any experienced advice will be very welcome !
Incidentally, I was looking for the price of the pump (Vaillant VP5ZE PWM S2, P/N 59866536, Grundfos 160967), but I could not find it anywhere on the web, which is surprising. Has it been replaced by a different model ?
Thank you
Alberto
I have uploaded pics of the boiler on my album but I am not sure whether they are visible to everybody.
