New Gledhill Stainless Lite Indirect Unvented alarming popping noises.

[samba1]

Happy Christmas everyone,

We’ve just had a new Gledhill Stainless Lite indirect unvented cylinder installed by Dyno. It is making an alarmingly loud popping noises when the hot water is being used, not always but very very often.

Mentally to me, it seems like the inner casing of the cylinder is flexing in and out (just like a plastic water bottle under a pressure change).

I have read that these are thin cylinders (hence the lite) and many have reported issues, even after a replacement.

Those of you experts out there who are familiar with this cylinder and it’s issues, is my best course of action to get Dyno to replace with another brand/model, rather than go with a replacement of the same brand/model?

Dyno have requested Gledhill to come on site, but I have read some posts saying the problem reappears after replacement. The visit will now take place in the new year, but I want to be prepared and not be fobbed off.

In your experience and expert opinion what is my best path here guys? Is it worth just insisting Dyno to get a refund and go for another brand/model (I’m assuming that is an option)? If so which one?

Thanks!

P.S. Dyno guys have checked the pressures, i.e. reduced the mains down to 3bar, and on Gledhill’s telephone advice reduced EV from 3bar to 2.8bar.

 

[king of pipes]

Ideally yes but its a new install so the combination set up should be factory set ? you need to make sure your putting 3 bar water pressure and at a decent volume 20 + litres a minute into the cylinder, if you take more out than you put in it can cause the problem your experiencing.

 

[king of pipes]

Below are examples of how it should be installed

 

[John.g]

There no attachments KOP.....

 

[king of pipes]

Hot and cold supplies ideally how it should be installed 😉

 

[moonlight]

Video watched, one thing I can see wrong supply taken from cold water prv not from inlet combination valve.

 

[John.g]

The point was made that if both PRVs are supplying water at the same pressure then system should work OK, I would think that you could have at least 0.5bar difference in the two and still have proper mixing but I would agree though and can't really understand why it wasn't done the "proper" way, I Iinclude a schematic once again which is quite clear, the EV is also wrongly installed so all these might conspire to cause noise in a paper thin unvented cylinder.

 

[samba1]

The point was made that if both PRVs are supplying water at the same pressure then system should work OK, I would think that you could have at least 0.5bar difference in the two and still have proper mixing but I would agree though and can't really understand why it wasn't done the "proper" way, I Iinclude a schematic once again which is quite clear, the EV is also wrongly installed so all these might conspire to cause noise in a paper thin unvented cylinder.

View attachment 67600

Thanks John.G I did question Dyno if the EV should be installed in the way it was, they said no. However, I was merely asking about the way it was piped, I.e. the flow of cold water has to make a 90 turn to go into the cylinder. Is this what you are indicating by being wrongly installed, or is it that it should be connected directly to the combination valve? I’m not 100% sure what ought to be the correct way…

 

[John.g]

I wouldn't be overly worried about a 90deg turn but I would much prefer to see a balanced cold mixing with the hot, a balanced cold means coming off the same PRV as the cold supply to the cylinder, ie the combination valve block. or whatever its called.
"I did question Dyno if the EV should be installed in the way it was, they said no." why didn't they change it then?.

 

[samba1]

I wouldn't be overly worried about a 90deg turn but I would much prefer to see a balanced cold mixing with the hot, a balanced cold means coming off the same PRV as the cold supply to the cylinder, ie the combination valve block. or whatever its called.
"I did question Dyno if the EV should be installed in the way it was, they said no." why didn't they change it then?.

Sorry, my typing is terrible!!!

Should read:

"I did question Dyno if the EV should be installed in the way it was, is it wrong? they said no that’s not a problem”

 

[John.g]

Well, if glendhill's installation is like the one I've posted there is no way that they will provide a new cylinder. They must have sold hundreds of these Stainless Lite, they can't all be noisy?.
A quick look through the installation manual doesn't show the position of the EV but it certainly shows the cold feeds taken off the combination valve.

 

[ShaunCorbs]

The inlet assembly is correct and the system is balanced without repiping the whole house, move on Jon neither of these would cause the popping noise

 

[TGF5454]

Hi samba1,

Did you ever resolve your issue, I have exactly the same symptoms and what sounds like an identical install.

 

[John.g]

Hi samba1,

Did you ever resolve your issue, I have exactly the same symptoms and what sounds like an identical install.

Is the expansion vessel sitting above your HW cylinder and piped from the cylinder hot water outlet as well?.

 

[John.g]

Also, if the expansion vessel is piped from the combination inlet group, ensure that it is NOT piped from upstream of the non return valve as shown (in the official Glendhill guide) but is piped downstream of the NRV, there may be a tapping for this from the ERV.

 

[samba1]

Hi samba1,

Did you ever resolve your issue, I have exactly the same symptoms and what sounds like an identical install

Hi samba1,

Did you ever resolve your issue, I have exactly the same symptoms and what sounds like an identical install.

Hi, yes sadly it was a case of swapping the cylinder. Replaced with a Joule and no issues at all now. My Gledhill cylinder had a new serial number sticker over a previous one, to me that suggests it was either reworked in the factory or a returned unit.

The date code was for November and the two numbers were 3-4 weeks apart. The whole situation was suspicious to me. There may be a perfectly good explanation for it but I struggle to see any other.

Check if you have any deformation on the outer skin to indicate any impact to the unit in transit. The other area of suspicion is the combination valve. Could just be a faulty batch. Mine was supplied with the cylinder and was made by Reliance Water Controls. The new Joule cylinder came with Caleffi combination valve.

if you still have the option to swap out I would try to entertain that idea. I understand that it’s not always a pragmatic option.

 

[John.g]

And the Caleffi balanced cold is also blanked off?.

 

[samba1]

And the Caleffi balanced cold is also blanked off?.

Hi John.g, yes exactly the same configuration as before.

 

[samba1]

Hi samba1,

Did you ever resolve your issue, I have exactly the same symptoms and what sounds like an identical install.

Have a look at this thread, I think the answer is now becoming clearer…

Gledhill Unvented Cylinder Loud Bang Hot Water Demand | UK Plumbers Forums | Plumbers Forums

Find Gledhill Unvented Cylinder Loud Bang Hot Water Demand Advice and Help. How-to Gledhill Unvented Cylinder Loud Bang Hot Water Demand in the UK Plumbers Forums advice boards on Plumbers Talk | Plumbing Advice | Plumbing Forum - Professional and DIY Plumbers and Bathroom Fitters Forum...

www.plumbersforums.net

 

[TGF5454]

Hi, yes sadly it was a case of swapping the cylinder. Replaced with a Joule and no issues at all now. My Gledhill cylinder had a new serial number sticker over a previous one, to me that suggests it was either reworked in the factory or a returned unit.

The date code was for November and the two numbers were 3-4 weeks apart. The whole situation was suspicious to me. There may be a perfectly good explanation for it but I struggle to see any other.

Check if you have any deformation on the outer skin to indicate any impact to the unit in transit. The other area of suspicion is the combination valve. Could just be a faulty batch. Mine was supplied with the cylinder and was made by Reliance Water Controls. The new Joule cylinder came with Caleffi combination valve.

if you still have the option to swap out I would try to entertain that idea. I understand that it’s not always a pragmatic option.

Thats not good news at all, ours is an early 2021 date of manufacture.

We are also using the RWC combination valve that was supplied with the cylinder. Which Joule unit did you go for? I don't think we could return at this point which is a real shame.

 

[John.g]

Thats not good news at all, ours is a May 2021 date of manufacture.

We are also using the RWC combination valve that was supplied with the cylinder. Which Joule unit did you go for? I don't think we could return at this point which is a real shame.

Would you mind posting a photo of the RWC combination valve installation and also where the expansion vessel is teed into it or teed into the system.

 

[samba1]

Thats not good news at all, ours is an early 2021 date of manufacture.

We are also using the RWC combination valve that was supplied with the cylinder. Which Joule unit did you go for? I don't think we could return at this point which is a real shame.

Hi,

The one I went for is: Joule Cyclone TCEMVI-0200LFC. I spoke to Joule technical who said that model range has 1mm steel compared to others which only have 0.5mm

 

[TGF5454]

Perfect thanks, I will look at them as an option.

 

[TGF5454]

Would you mind posting a photo of the RWC combination valve installation and also where the expansion vessel is teed into it or teed into the system.

Sure Its like this:

 

[John.g]

Just wondering if all those Glendhill cylinders, even the ones with the proper insulation curing time, are behaving like this/these ones where the EV is tapped off the PRV and right at the inbuilt check valve. If the EV pre charge pressure is incorrectly set and not at least 0.2bar < than the PRV pressure it may be enough to upset these paper thin cylinders.

 

[TGF5454]

I believe ours was originally set to 3.0 as per the manual & sticker on the tank but later dropped to 2.8 which reading above is also Gledhill advice.

Shame because it’s a good looking tank, buts it’s way to noisy to live with.