Viessmann Vitodens WB1A Noisy (Video attached!)

[mysteryman]

Just try it the way I suggested last night. You need to induce a flow from the header tank, through the boiler, and out to drain, so as to flush the air out. Close a pump valve to ensure that the flow is through the boiler, not all round the system, obviously with the pump and boiler off. I can't advise you on exactly how to do this without knowing the relative positions of the boiler, cold feed, vent, pump, and drain offs. You can't get a rapid temperature rise with the correct flowrate.

 

[Kev F]

I'd try mine first, less chance of cocking up, ie pump valve snaps or leaks etc

 

[JohnD]

oooh, you boys are so competitive!

 

[Kev F]

Not really just trying to make it easier and less of a chance of creating more problems

 

[JohnD]

An update:

Well I haven't done any draining yet, but I have had the pump turned up high for 24 hours to try to blow the air out, and the noise is much quieter, though still faintly present as the flow temp reaches 70+ and the flames are on full.

The flow temp rises much more slowly now.

The pump is a self-regulating Alpha 15-60 130, which I understand is ample for a domestic system. It struck me that if air is obstructing the flow, the Alpha would regulate itself down to some extent. I pulled out the Pump instructions and see that as well as setting it to the thick end of the arrow, which is for "increased head for variable-load system with high resistance," it also has three click-settings for low/med/high constant load. High is used when venting the system.

So I have turned it up to the high fixed click, to see if that helps. The pump whirring is not very noisy, but it is certainly detectable now (on the standard setting it is practically inaudible).

 

[mysteryman]

That's good. If there is still residual air in the boiler which the pump can't force out when on maximum, you will need to follow my method. Otherwise, you should be OK. Is the pump pumping downwards? You should not be able to hear air in the pump or the boiler at any speed.

 

[JohnD]

pipes on pump are horizontal. I can't hear air in it, I can just hear the hum of the motor. Once I am sure any air has gone, I'll turn it back down.

 

[Agile]

I am glad that my suggestion is apparently solving the problem.

After about three days all the air that is going to be removed should have gone.

Tony

 

[mickyg]

it's one of those self-regulating Grundfos Alphas.

bleuggh