vented cylinder vent pipe capped... advice..?

[Artisan Bathrooms]

Hi guys,

Been to see something I've not come across before. Have to replace a whole house pump for hot and cold water 'cos the old one's broken and it needs to be a negative head anyway. Cold feed to pump comes from cws in loft space and hot from cylinder. The hot comes straight out from the top of the cylinder and then Tees off into the pump. All perfectly normal so far. However, what should be the vent pipe has been capped with an air vent cap about a foot up from this. Any expansion can therefore only be back up the cold feed and any air can presumably be bled off the vent cap. There has been a fair bit more bodgy plumbing in the flat but this is the bit I'm not sure of. Is it likely to cause me problems..?

Any advice gratefully received, etc.

Cheers...

 

[waterworks]

Dangerous bomb waiting to go off.

 

[seco services]

try disconnecting the cylinder stat you'll soon see.

 

[heatingman]

Wouldn't recommend you leave it like that, the vent is a critical safety warning pipe/device and must not be blocked/valved/obstucted in any fashion. It must also rise vertically to above CWS. If you leave it as such your wide open to any ramifications if there's a problem later on. The customer might not like you for pointing it out, just emphasis the safety factor.

 

[Artisan Bathrooms]

Ok - thanks for that guys. You've pretty much told me what I thought anyway. I've certainly never seen this done before... They've had a loft conversion and presumably the builder found it easier to just cap the vent pipe than re-route all the pipework.

The customer told me that "he wasn't really a plumber... more a jack of all trades..."

"No kidding..." was my reply.

 

[gasandoilman]

Best solution is to pressurize system as they have the loft space taken

 

[supergas]

i know the local authority near me cap vent pipes off if the system is dragging air in, their theory is that it will vent and expand through cold feed
very naughty

 

[doitall]

And if the cold feed is turned off or becomes blocked the cylinder will implode

 

[Kev F]

lots of combined cold feed and vents round my way, never had a problem, all piped in 22mm.