Leaking/Whining Unvented Cylinder

[ch3otlc]

Howdy,

We had our loft tank removed and our cylinder replaced with a Worcester Greenstore unvented cylinder and have a few issues with it.

Firstly, it is leaking pressure. We were advised it should stay around 1.2 bar when cold but have had to refill it semi-regularly. We cant find a leak on any of the new joints (we had new radiators and some shower pumps removed when it was installed) and can't see any wet patches anywhere. Is there another reason why this could be happening or is there likely to be a leak somewhere we haven't found yet? Any suggestions of where a leak might be? On the central heating circuit somewhere?

Secondly, it is making an awful whining sound on occasions, usually when the motor is on (but not coming from the motor). Is this something resonating? Air in the system?

Will get a plumber in when all this nonsense dies down...

 

[SJB060685]

So your heating system is losing pressure? What motor do you mean with regards to whining?

 

[ch3otlc]

I meant the circulating heating pump, sorry! It doesn't whine/whistle all the time, but it stops dead as soon as the pump stops. It's loud enough to the point of distraction now I'm around it all day. Edit - and it isn't the pump itself whining, it is hard to pinpoint, I can't tell if it's from within the cylinder or if it's some pipework underneath it.

 

[Scott_D]

Some pictures always help us understand what you are describing

 

[ch3otlc]

No problem, here's the setup in the airing cupboard. The whining doesn't seem to be coming from any of the external pipework, sounds like either within or maybe under the cylinder.

 

[SJB060685]

The pressure gauge in picture is for the heating and not the cylinder. A few thinks can cause your problem

 

[Scott_D]

Is the noise when hot water is being drawn or heating is on?

 

[Jones82]

Sounds like air in the system generally, try bleeding all high spots usually towel rails / radiators on the top floor. Don’t forget to top the pressure up via the filling loop next to the gauge. To around 1.25 bar. There is also an automatic air vent next to the filling loop which is the most likely source of the pressure drops. Keep topping it up for a week or so then close the top of the air vent. If the pressure still drops you may have a leak some where.

just noticed there’s auto air vents on the flow and return. Make sure they are both open, it’s a little plastic screw on the top, slacken it off finger tight and you may here a little pssss every now and then as air escapes. This is usually the cause of pressure drops, especially on a new system

 

[ch3otlc]

RE - Leak - It has been dropping pressure since it was installed in December.


Re - Whining - The wireless receiver lights up, the pump turns on, its nice and quiet until the wireless receiver turns off, * then * I can hear something motorised start up (zone valve actuator? though the whining isn't coming from either of them) and then the whining happens until the pump itself stops.

 

[Jones82]

To the left of the picture, bottom left you have an auto byepass valve, this may need adjusting. You can open it a little more but don’t open it too much as it’s a direct route back to the boiler, too much and the radiators won’t get hot. I think I can also see a lever valve on the return instead of a gate valve which could also be opened a little more. Take note of their original positions! Then you can adjust them back if needs be.

Essentially you are adjusting the flow of water around the system, known as balancing. Think of it like a river. We fit various controls to limit or encourage the flow of water around the system

 

[ch3otlc]

This thing? What should I try setting it to?

 

[Jones82]

Looks like it is on 0.3 now. Try 0.2 see if the noise stops. Adjust it via the black plastic nut. Anti clockwise

 

[ch3otlc]

Got it as far as 0.25 and the noise stopped. Fantastic! My wife was starting to give me aggro over it...

Just need to keep an eye on that pressure now...

 

[ch3otlc]

An update on this.

I noticed that my radiators are getting hot when the heating is off but the hot water is on. The internet suggests this is a faulty 3 way (though looking at our setup we only have 2 way?) valve that just needs replacing (the valves were not new with our new cylinder, they were from our old system).

Could this issue be related to why we're losing pressure?

Thanks

 

[SJB060685]

You should have 2 two port valves, one for HW, the other CH. Has this been a constant problem or only recently? Valve could be partially stuck open or you could have reverse circulation

 

[ch3otlc]

You should have 2 two port valves, one for HW, the other CH. Has this been a constant problem or only recently? Valve could be partially stuck open or you could have reverse circulation

We've only just noticed due to the warm weather and us being stuck in the house. First time it's warm enough to have the heating off.

 

[SJB060685]

With just HW being called for, place your hand on flow of CH after zone valve, if you feel heat and flow then the valve. If not you could have reverse circulation where hot water exiting cylinder coil is pumped back through return of CH. That can be rectified with a NRV, although the pipes should have been installed to prevent the need for one

 

[ch3otlc]

With just HW being called for, place your hand on flow of CH after zone valve, if you feel heat and flow then the valve. If not you could have reverse circulation where hot water exiting cylinder coil is pumped back through return of CH. That can be rectified with a NRV, although the pipes should have been installed to prevent the need for one

The pipe on the other side of the zone valve is warm, much cooler than on the feed side but warm all the way down (maybe 1-2 ft of pipe), suggesting it is leaking through slightly?

 

[SJB060685]

So the flow after CH zone valve is warm? Obviously there will be a certain amount of heat transferring through the pipework but usually minimal if all is well. I'd want to be certain before saying for sure that the valve was sticking, although if you're getting CH when calling for HW its only going to be down to a couple things.

 

[ch3otlc]

The gift that keeps on giving. Our water now tastes awful. Rubbery perhaps? Are we getting water from the cylinder back flowing into our tap water now?