New noise after technician visit

[LeeroyK]

So I had a problem with low HW pressure which was much improved by switching out plastic piping for copper. That was done yesterday.

Apparently the only thing he did inside the boiler was check the gas flow rate.

We have a new noise now that wasn't there before, sounds like a jet spinning up, it might only be when demanding HW, doesn't seem to do it with CH (that might be a red herring).

Previously HW and CH the boiler just sounded like a boiler coming on now, like I said, it sounds like there's a little jet engine inside.

It could just be he put the cover back on wrong and now something it touching the case which shouldn't be.

Is it likely to be the fan?

I don't want to be calling people out if it's not needed.

 

[opps]

What happens if you push your hand against the boiler? Does the sound change?

I am not a plumber, it might help others if you let them know which boiler you have. Additionally, do you mean that the mains supply was replaced?

As a non-plumber, I think it unlikely to be the fan. The pump seems to me to be more likely to be responsible for the noise

 

[LeeroyK]

What happens if you push your hand against the boiler? Does the sound change?

I am not a plumber, it might help others if you let them know which boiler you have. Additionally, do you mean that the mains supply was replaced?

As a non-plumber, I think it unlikely to be the fan. The pump seems to me to be more likely to be responsible for the noise

Thanks, here's the previous post with all the details. It was just the run from the nearest cold feed and return into the hot water system.

https://www.diynot.com/diy/threads/new-combi-install-help-needed.576791/