Humming vibrating noise from hot water cylinder ....?

[Jonnym123]

I have 18month old new central heating system with valiant boiler and gledhill hot water cylinder. Recently I have been getting a loud humming and vibrating noise that seems to occur only when the hot water is being heated but the heating is off...

Although there was a time it only happened in the morning now for the last week it has been happening in the early evening.

My hot water heats in the morning from 6 to 9 and then restarts heating at 4pm... It seems by 6pm the noise starts every time the thermostat turns the central heating off... The noise stops as soon as I put the central heating back on..or once the hot water stops heating at 7pm...Any ideas ? ?.

 

[dcawkwell]

I have 18month old new central heating system with valiant boiler and gledhill hot water cylinder. Recently I have been getting a loud humming and vibrating noise that seems to occur only when the hot water is being heated but the heating is off...

Although there was a time it only happened in the morning now for the last week it has been happening in the early evening.

My hot water heats in the morning from 6 to 9 and then restarts heating at 4pm... It seems by 6pm the noise starts every time the thermostat turns the central heating off... The noise stops as soon as I put the central heating back on..or once the hot water stops heating at 7pm...Any ideas ? ?.

Perhaps 2 port valve not opening fully when hot water is on.
Find the two port valve on the flow to the hot water tank and use the tab
on the side of the valve the open it manually and latch it. Does the humming noise go away?

Other possibility is the motor of the two port valve.

 

[Jonnym123]

YES - I waited for the noise t start again this afternoon and when It did I latched the two port valve and it stopped! I'm very impressed! Thanks..... BUT then when the heating went back on the latch clicks out and it's back to square 1 as the noise starts again the next time the heating goes off....

What does this mean ? how can i fix it?

Thanks for you help ......

 

[mysteryman]

There is a maximum permissible flowrate through the coil on these cyls. You may need a regulating valve to limit it.

 

[Jonnym123]

Would the noise not have started from day 1 if that was the case rather than 18 months down the line.....?

Is the flow rate linked to the system pressure? Should I try to reduce pressure from the system by bleeding radiators? Would that drop the flow rate?

Or do you think maybe the two port valve is broken and needs replacement.....

Thanks for you time by the way I appreciate the help.....

 

[dcawkwell]

YES - I waited for the noise t start again this afternoon and when It did I latched the two port valve and it stopped! I'm very impressed! Thanks..... BUT then when the heating went back on the latch clicks out and it's back to square 1 as the noise starts again the next time the heating goes off....

What does this mean ? how can i fix it?

Thanks for you help ......

If the port valve has been moved across and latched into the little notch
it shouldn't move at all no matter what the heating is doing.
Sounds like you need the 2 port valve replacing to sort the problem though.
New 2 port valve about £20 to £30 pounds more for a well known name
like Honeywell.

 

[Jonnym123]

Thanks I have arranged a plumber to come this week to try replacing the valve. Thanks for your advice which sees to have been pretty spot on... Merry Xmas...

 

[Jonnym123]

plumber came and couldnt find anything wrong with two prot valve, checked the system and couldnt find anything else obviously wrong.... the wierd thing is that the system works fine all morning ( water heated 6am to 9am ) but then the noise comes in afternoon ONLY ( water heated 4pm to 7pm) ..

plumber was baffled and said will look into it and discuss with his plumber pals ...

seems the key is why would it work fine for 18 months , then fine in the mornings ????

 

[dcawkwell]

plumber came and couldnt find anything wrong with two prot valve, checked the system and couldnt find anything else obviously wrong.... the wierd thing is that the system works fine all morning ( water heated 6am to 9am ) but then the noise comes in afternoon ONLY ( water heated 4pm to 7pm) ..

plumber was baffled and said will look into it and discuss with his plumber pals ...

seems the key is why would it work fine for 18 months , then fine in the mornings ????

If you open the two port valve manually and the noise goes away it is the 2 port valve. Probably sticks in the afternoon when the system is hot.

 

[Dorsetdweller]

I’ve got the same problem. Did you resolve it in the end? Was it the 2 port valve? Many thanks

 

[winston1]

11 year old thread. Do you really expect an answer?

 

[Dorsetdweller]

Good point thanks