Automatic Bypass Valve continually rattling.

[SquiddlyDiddly]

I have had an automatic bypass valve fitted to our central heating system. I notice that when the central heating is on the valve is continually rattling. My plumber said that was OK and since the boiler is in a utility room, the noise doesn't matter.

I thought that the bypass valve would in effect remain silent and only come into operation if the zone valve closed and the pump was still running or if all the TRV's were closed and the CH was still running.

It could just be a case of adjustment but I really want to know more so I can advise the plumber. He did admit that he had not fitted an automatic bypass valve before.

 

[fazedup71]

is the valve fitted the correct way round? check the arrow on the side of the valve it should follow the direction of the flow pointing to the return.

Does your valve make a screaming sound? these valves need setting up, if the valve is not set correctly it can scream like a biatch. He shouldn't have fitted it if he didn't know how to set it up.

If yours is the sort with the dust cover and the brass adjustment knob underneath they can make a horrid noise when not set up, a quick although not very accurate thing to do is turn the brass knob, if it is loose the noise should go away as you alter the setting.

 

[SquiddlyDiddly]

Yes the valve is fitted the correct way - arrow in direction of flow. It is a Honeywell DU145.

No it doesn't scream. There is a rattle coming from valve continuously when th CH is on. I am presuming that shouldn't be the case. The valve is set tp Number 2. It is difficult to get at - need angled screwdriver to release the cap so you can change to a different number, so I have left it.

Basically. I just want to say to the plumber that the continuous rattle isn't right and ask him to sort it out. He is coming back in a week or so to do a pressure clean so I want to be able to tackle him then.

 

[45yearsagasman]

Honeywell didn't design them to rattle, end of.

 

[Boilerman2]

Are you sure it is the Auto by-pass rattling - i have NEVER heard one make such a noise, your description is more likely to be a rattling gate on one of your pump valves (which is probably very near to the auto bypass)
make sure both pump valves are fully open

 

[SquiddlyDiddly]

Thanks All. I will turn it over to the plumber to sort out.

 

[Agile]

I would usually set them to JUST allow a small flow when about 60% of the TRVs have turned off!

That needs to be done AFTER the system has been balanced!

Tony

 

[ironsidebod]

I've recently removed one of these auto bypass valves because of the noise it made (still have other issues to sort ).

They do rattle a lot - the head for setting is loose on the body so when flow goes through the valve it vibrates.

OP: If your plumber can't solve it i.e. it's not a set-up problem then ask him to change it to another brand.

 

[SquiddlyDiddly]

But should it be in operation (rattling) the whole time or only if it comes into play work? My one is rattling the whole time the CH is turned on. This would appear to be allowing flow through the bypass all the time rather than when the zone valve or TRVs were switched off.

It is not a major issue it is simply annoying to have this rattle going on and I just want to know if I would be in my rights to ask the plumber to change it or at least adjust it.

 

[gaswizzard]

I've had to change a few of these valves (honeywell) , the straight pattern type tend to be more of an issue than that of the angled type , I agree it's an annoying rattle.