Socdesign,
Sounds like the second cylinder has done exactly what mine did on the second go round, it was fine for a few weeks before starting to pop.
The popping over several months will start to get worse from my experience and you might get it popping even when no hot water is drawn off.
I've recently installed a new cylinder to replace the second Gledhill because the customer couldn't live with the noise and it wasn't getting resolved with Gledhill.
I installed a Plumb Centre cylinder and so far so good.
I'm trying to get a refund from Gledhill but not sure if successful yet?
We need to make them aware that its not a single case because they are trying to suggest that its an installation fault.
Gledhill made over complicated sludge buckets and now they can't even make a simple unvented cylinder.
It will take a lot more than marketing hype to get them out of this one!
If you need to find a tradesperson to get your job done, please try our local search below,
or if you are doing it yourself you can find suppliers local to you.
Select the supplier or trade you require, enter your location to begin your search.
Please select a service and enter a location to continue...
Are you a trade or supplier? You can create your listing free at DIYnot Local