Very Loud Noise Like Car Skidding When Hot Water Heating Is On

happyplants

I've read a few posts about various noises from heating systems, but I haven't seen anything describe this sort of noise.

We have an oil boiler and tank in a plant room. In our attic we have a cold water tank which has 35mm feed in and 28mm feed out with a 15mm break off to the heating system pressurisation set. Now, all the heating is off.

The tank has a 35mm hot out and a 28mm return and the hot is just piped direct to the taps etc.

Edit: To add, its a well system where the water is taken from the ground and put through a purification system out in the plant room. The cold is them pumped to the tank in the attic and then pumped back to the tank for heating in the plant room (I didn't build this house - still getting to grips with the choices made).

However, in the last few days when I turn just the hot water on, after a while I get this god awful noise which sounds like its coming from up high which I can describe as sounding like a car screeching to a halt. It took two listens for my wife to accept it wasn't a car out on the road!

Would anyone have any ideas? I'm thinking since the water is pumped to the tank in the attic and back to the heater, its something to do with the water leaving or entering the tank in tank in the attic, but just can't figure what could be wrong that suddenly is making that noise.

The Continental Op

First question I have is what type of pipes do you have and how are they secured. For example copper pipe held up up nails is likely to make more noise from water hammer than plastic pipe that is well clipped back. Probably not that but worth ruling out.

After any chance this is some form of pressure relief valve kicking in? Maybe a mains pressure reduction valve thats full of muck?

con747

https://www.boards.ie/discussion/2058302250/very-loud-noise-like-car-skidding-when-hot-water-heating-is-on

Maybe the easiest way to find out is by turning it on while in the attic so you can hear and see what is causing it.

whizbang

Almost definitly the pump feeding the cold water tank.

Quite often tank fill valves (Float valves) make a wailing or howling noise, but it starts at a low pitch, and builds up to a high pitch before fading out. (or going supersonic!) as the valve shuts off.

happyplants

https://www.boards.ie/discussion/comment/120761975#Comment_120761975

Thank you for that. We've lived here two years now and never heard it before at all, hence the concern. The pump is very, very far away from the noise location though - would that make a difference?

happyplants

https://www.boards.ie/discussion/comment/120761400#Comment_120761400

Some sort of pressure relief was what I was guessing as it only happened in the last week or so when it was very, very hot and the hot water system had been on for a long time. It wasn't really a pipe banging noise though and sounded absolutely like some sort of pressure issue (just to my ears anyway).