Megaflo cold feed hammering.

TAFCFC · May 21, 2022

Afternoon all, I’ve recently started getting a loud vibration coming from the cold feed. Only when I’ve got the hot tap on. Any ideas what it could be? I’ve managed to stop the vibration by turning the blue valve slightly. Thanks in advance.

Chuck · May 21, 2022

When was the system last serviced/checked? (Should be annually) The tank may just need the 'air bubble' inside the tank topping up. (This accommodates expansion but also acts as a water-hammer suppressor?)

king of pipes · May 21, 2022

As above these need servicing annually ? , There are instructions you can follow to recharge the internal air gap if you feel compent ? this may help but please employ a G3 qualified engineer for parts and service work . Kop

TAFCFC · May 25, 2022

Chuck said:
When was the system last serviced/checked? (Should be annually) The tank may just need the 'air bubble' inside the tank topping up. (This accommodates expansion but also acts as a water-hammer suppressor?)

king of pipes said:
As above these need servicing annually ? , There are instructions you can follow to recharge the internal air gap if you feel compent ? this may help but please employ a G3 qualified engineer for parts and service work . Kop

I had a system boiler installed 6months ago and had the cylinder connected up. I assumed they serviced as part of installation but maybe not. I’ve recharged the air gap but made no difference. I’m on the ground floor so connected a hose to drain cock which was a step not on the cylinder. I’m getting hammer when I demand hot and flow fluctuating when I demand cold for around 30seconds not sure that helps diagnose.

king of pipes · May 25, 2022

It's could quite possibly be a faulty combination valve as I've stated a G3 qualified engineer is needed for work on these . Kop

TAFCFC · May 27, 2022

king of pipes said:
It's could quite possibly be a faulty combination valve as I've stated a G3 qualified engineer is needed for work on these . Kop

Had a G3 engineer out yesterday, he said he’s not quite sure what it is. He’s said it definitely not water hammer, said to clean the PRV which I did which did nothing. But what did fix it was turning the nut on the end of the PRV 2 times. But I’m now worried if I’ve increased the pressure is it dangerous?

Chuck · May 27, 2022

TAFCFC said:
Had a G3 engineer out yesterday, he said he’s not quite sure what it is. He’s said it definitely not water hammer, said to clean the PRV which I did which did nothing. But what did fix it was turning the nut on the end of the PRV 2 times. But I’m now worried if I’ve increased the pressure is ialift dangerous?

No G3-qualified engineer I know would tell the customer to 'clean the PRV' themselves. They would do the job and check the pressure settings and safety devices as part of the job.

TAFCFC · May 27, 2022

Chuck said:
No G3-qualified engineer I know would tell the customer to 'clean the PRV' themselves. They would do the job and check the pressure settings and safety devices as part of the job.

He wasn’t doing the job last night. He was local and swung by to diagnose as the videos and pics I sent didn’t help him. He just told me to give it a clean and if that fails he’s happy to change the PRV £90 part £70 labour. Maybe he felt comfortable telling me to do it as I’m a competent builder.

Richard84 · May 30, 2022

Hi,

I seem to ahev a similar problem (sorry if this not the same as you TAFCFC) My Megaflo Eco System Unvented Cylinder is making a loud band.

This occurs when the hot water heating is on and when the cylinder heats up to temperature, once at temperature the motorized valve closes and there a loud bang, which causes the pipework to vibrate.

I have attached a video which shows the problem occurring.