Unvented cylinder pressure - but boiler now loosing pressure

[mark7979]

Hi.

My unvented cylinder was recently replaced with a Santon Premier Plus Cylinder. This was done by a plumber qualified for the job. He also fitted a magafilter and flushed the system clear + filled inhibiter.

The problem is that the boiler (Voykera Mynite 28e) is now loosing pressure over the course of the week and needs to be filled weekly.

The plumber has checked all radiators etc. and cannot find any leak or cause. This plumber is quite new at the job and has only had a few months of working experience after qualifying - is he missing something?? How can the change of cylinder cause this problem? The boiler didn't loose pressure for years and now after the fitting it suddenly is - there must be a connection!!??

Could the boiler have been affected or strained due to the flushing (it was making a noise when running after the flush)?

What is the likely cause - any help greatly appreciated.

 

[joe brown]

The radiator in the hall, Check the bleeding Valves!

 

[SimonJohns]

You'd notice a leak of that size

Have him to check your expansion vessel. After having a system with that much filling and draining, my bet would be that the diaphragm has split

If he's unsure how to check it. Here's how

Press the schrader valve on expansion vessel on boiler( not cylinder)
If you get water. It's broken. Replace
If you get air. Get a tyre pressure gauge and check pressure

But keep your eyes peeled for a leak also!

 

[Nat]

Check there is no water going through the tundish when the boiler heats up after filling the primaries to usual pressure.