New combi install making water hammer noise when heating is on

[mutley racers]

Hi, i have been to a clients house in which they had a combi installed and new rads. When the heating is on, the pipes all of a sudden send a shuddering noise that rattles the boiler.

I have noticed that the thermostatic valves are all over the place. On the flow and then on the return.

Is this the problem?

They should all be on the flow or the return, not on both hey.

 

[bob the plumber]

modern trv's and valves are usually take bi-directional flow, if there old they will knock as they will not allow for water to pass thorugh them the wrong way, i would imagine this is your problem plus there could be a bit of are in the system by the sounds of it

 

[Puddle]

In theory it does not matter if they are duel flow,however I always like to put on the flow if possible,I have also had quite a few faulty multi directional valves,that still vibrate when closing against the flow of the pump,maybe this is the problem here

imho

 

[AWheating]

it would depend on the valves and wether or not they are designed to be fitted on the return or not. Most new trvs can be fitted on the return.

does the system have a auto bypass? they can sometimes cause what you have described.

 

[mutley racers]

everything is new. All new pipework, new rads the lot. All was bled also.

So, are you saying you can put the trv's on flow on one rad and return on the other?

 

[mutley racers]

I did think of an auto bypass, but i looked in the instructions while there and it doesnt mention to fit one

 

[mutley racers]

They still have the instructions for rad valves, and they are bi-
directional

 

[desrob]

They still have the instructions for rad valves, and they are bi-
directional

although they are bi-directional valves and can be put on either flow and return, you still have to adjust them accordingly

 

[bob the plumber]

boiler over heating water makes a bloomin dreadful noise, when is the noise happening....when the boiler first fires or when its running for a bit?

 

[mutley racers]

the boiler is a MAIN ECO RANGE 25. If this helps. The website does say it has an integral bypass in it

 

[mutley racers]

when it is running for a bit

 

[AWheating]

is the bypass adjustable?

 

[mutley racers]

it does not say if it is adjustable or not on the web.

Desrob, what do you mean, adjust the trv's?

 

[stani]

some trv's have to be manually changed to go either on the flow or return, can't remember which make it is, but do know they are out there, its only a matter of adjusting a collar on the top of the valve body.

 

[mutley racers]

well i have never heard of that. Also, it did not say it on the instructions they had.

Is there a way to tell if it is a faulty trv? Like turning each one off suddenly and seeing if it shudders?

I can't see any where on the main site about the by-pass being adjustable. I sit possible i might have to fit an external one?

 

[GQuigley67]

on the danfos valves u need to change the flow of direction

 

[mutley racers]

well, i just told the custard on the phone to take all the trv heads off, and all is fine. So am going back there wednesday, and am going to put the valves all on the flow.

Am sure this will cure it.

I shall remember that about the danfoss valves.

Thanks guys

 

[GQuigley67]

you will notice 2 arrows on the valve, 1 going up and going down, you need to rotate the brass part of the valve to suit the flow of direction, best leaving TRV heads off until you have fired up boiler and determined which one is which

 

[mutley racers]

ok cool. I shall have a look for this. So, is this on all bi-directional valves? This little arrow?

 

[GQuigley67]

its on the danfos bi-directional valves, thats the only ones im familiar with really i use them all the time

 

[mutley racers]

ok nice. These are not danfoss. But i shall check these out to see if they also have them.

Thanks for all your help guys

 

[stani]

no. thats the bloody problem, this is one of those 'read the instruction' things, you never do, it was my lad who told me, swore at him for wasting time, then had to grovel for rest of day because he kept mentioning how much time he had saved me.

 

[fastnova]

Just would like to add ive fitted new TRV's correctly and had them chattering.. It was a manufacturing fault with the valve, was only one and it was a danfoss as described. So if you move them all to the flow and still get it, turn each valve off very slowly until you get the chattering noise to find it.

Just because something is new doesn't mean it always works lol

 

[mutley racers]

He he. Thats funny stani.

I am definately learning that, about things working when ''new''. A shower pump last week, and now trv's the next. What a lot of fun.

 

[mutley racers]

Well guys,i have been back to the flat today and swopped all the valves onto the flow. All of them, apart from the bathroom were on the return. So i change them, then go to the bathroom to slowly close the valve, and guess what, the hammering noise starts. So, i go to all the others i have just changed to do the same thing, and all is good.

Can you honestly believe it! Out of all of them, the only one which was on the flow, that i did not need to change, was the culprit. Ha ha ha. How funny is this job!!!

The guys that i was working for were really nice. A couple of gays. They gave me £200 tip. SO i went straight to pts and bought meself a nice van vault tube carrier for £100. Lovely.

This past 2 weeks has been great for tips. Last week i did a bathroom change and was given £130 tip.

Pucker!!!!!!

Thanks for all the help guys