New Gledhill Stainless Lite Indirect Unvented alarming popping noises.

[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.