Central Heating Port Valve Water Hammer

[Johntheo5]

If its (and the other Zone valves) are installed on the boiler flow pipe, which they should be, then the arrow should be pointing in the direction of (with) the flow and pointing towards the rads, similarly, the cylinder zone valve should be pointing into the cylinder etc.

 

[BlueLoo]

Only the central heating valve . It is interesting you are asking the question about the bypass valve installation. Boiler initially installed without external bypass because plumber said this boiler had an internal bypass. When I got a Vaillant engineer to do my annual service he wasn't happy there was no external bypass so go the plumber back and he fitted it. Picture below - not sure of the make and have not touched setting since plumber installed bypass valve.

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Ffs

Some background. Went from vented to unvented system 5yrs ago when I added an extension to the house. I have 15 radiators and underfloor heating. Boiler fitted was a Vaillant Ecotec plus 637. It's a 3 port valve system for heating, hot water and underfloor heating. Water cylinder is 290 litres.

Only issue I have left that is has been dragging on for 5yrs is what looks like water hammer when the heating motorised port valve closes when boiler goes into pump over run. So get this regular banging all day long.

I've checked to make sure the direction of the valve is fitted right way (green arrows in 3rd picture below) and it looks ok. Not sure what the issue is. I've attached some pictures of my heating system.

Any help appreciated. Thanks.

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From the boiler iom:

3.11.2 System by-pass
An automatic system by-pass is provided in the boiler.
The boiler is suitable for use in systems with thermostat-
ic radiator valves and no additional by-pass is required.
The by-pass valve is adjustable, see section 5.8.

If true (you should check yourself against the specific boiler you have) you have a an external ABV fighting an internal one. No wonder the plumber left it full open.

However, you probably could close it full tight and see if this helps.

 

[RK_London]

However, you probably could close it full tight and see if this helps.

You mean close the external bypass fully?

 

[BlueLoo]

You mean close the external bypass fully?

Yes