Hello everyone and thanks in advance for any idea you may have on my problem.
Here is the situation. My boiler is a vaillant ecotec plus (combi) connected to a a series of radiators and a water tank with a "Y" scheme. Boiler works fine. The only problem is it wont "restart" while it is still hot and constantly goes into pump overrun. By "hot" I mean basically less than half an hour since switched off. This obviously causes an issue for instance if the thermostat is near its temperature (in which case the boiler would normally go on and off regularly). I have made a video showing the issue very clearly (with a target temperature of 55 degrees) which you can see here
. The problem can be seen near 1'20''.
Basically the boiler makes a normal start until it reaches 55 degrees. Then it stops for a couple of seconds (why?) while the pump is still running (temperature goes back down a bit). And then the boiler goes back on at full speed. Temperature goes back to 55 quite quickly and then continues to increase until 57 where the boiler goes into pump overrun (security mode).
I had a few professional plumbers having a look. First told me to change the whole thing. Then got told to not change anything on the basis that we could live with it as is. Recently was told that it could be an issue with the heat exchanger / pump / blocage. I had the system drained - then a power flush. Then a new pump installed. But still the same problem. I am now thinking more about an issue with the boiler itself. Maybe a sensor doesn't work properly. Although it seem the work fine when starting from a cold boiler. I also had some doubts about the expansion vessel (cannot get any air from the valve) but pressure seems ok so not sure it is actually a problem. The only last piece we didnt change is the 3 port valve (which seems rather rusty) but dont see how it could be connected with the problem.
Any idea?
Thanks a lot
Teebob
Here is the situation. My boiler is a vaillant ecotec plus (combi) connected to a a series of radiators and a water tank with a "Y" scheme. Boiler works fine. The only problem is it wont "restart" while it is still hot and constantly goes into pump overrun. By "hot" I mean basically less than half an hour since switched off. This obviously causes an issue for instance if the thermostat is near its temperature (in which case the boiler would normally go on and off regularly). I have made a video showing the issue very clearly (with a target temperature of 55 degrees) which you can see here
Basically the boiler makes a normal start until it reaches 55 degrees. Then it stops for a couple of seconds (why?) while the pump is still running (temperature goes back down a bit). And then the boiler goes back on at full speed. Temperature goes back to 55 quite quickly and then continues to increase until 57 where the boiler goes into pump overrun (security mode).
I had a few professional plumbers having a look. First told me to change the whole thing. Then got told to not change anything on the basis that we could live with it as is. Recently was told that it could be an issue with the heat exchanger / pump / blocage. I had the system drained - then a power flush. Then a new pump installed. But still the same problem. I am now thinking more about an issue with the boiler itself. Maybe a sensor doesn't work properly. Although it seem the work fine when starting from a cold boiler. I also had some doubts about the expansion vessel (cannot get any air from the valve) but pressure seems ok so not sure it is actually a problem. The only last piece we didnt change is the 3 port valve (which seems rather rusty) but dont see how it could be connected with the problem.
Any idea?
Thanks a lot
Teebob
