Quick unvented query

[Riley]

Had a customer ask about installing one today.

Tested water pressure and flow
standing 4 bar
working 1.2bar
lpm 12-13

I'm pretty new to unventeds on my own. Would I be right in saying that without a mains upgrade I'm gonna struggle to get much in the way of benefits ??

cheers

 

[townfanjon]

Yep no chance on that one mate , pressures low but it's your flow that knacks it

 

[Riley]

Thought as much mate thank you.

 

[townfanjon]

Most need at least 20 lpm , 25 and upwards better, I have done a few on just under 2 bar working .

 

[Riley]

Cool, i just wasn't sure if there may have been a suitable cylinder no worries though. I still have a new boiler.

 

[Ch4 plumbing]

GAH Duelstream state theirs will work on a 15mm main at 1.5bar and 9lpm, never fitted one though?

 

[Riley]

Cheers ch4 Not gonna be that great a performance though is it. Shame

 

[Riley]

Could look at an accumulator I spose

 

[Ch4 plumbing]

It's an unvented cylinder with a huge accumulator to make up for the poor cold main input, need some space.

 

[Riley]

That's the other issue. Cylinder cupboard is snug. Was always gonna have to be slimline. May knock the idea on the head before I go too far

 

[iiplumbing]

Hi Riley

You may want to look at the Megaflo see what heatrae say about it.

Because of the air bubble in the cylinder it kind of acts as an accumulator (as long as it doesn't loose the bubble!!)

Give it a shot, might be ok.

Where did you take your flow measurement from?

Russ

 

[Riley]

Flow and pressure was from outside tap crazily first in line on the mains in. Piped completely wrong then turned on kitchen sink for working pressure

 

[iiplumbing]

In that case flow could be affected by any inline check valves on your outside tap.

If the kitchen sink has flexible tap tails and is a monoblock ceramic disc then that takes the wack out of flow rate

take the flow rate from the cold bath tap, that will be the best/highest reading, or make yourself a temporary connection near the stopcock.

 

[Riley]

Bath is tank and pump fed so that's difficult

 

[Riley]

Bath is tank and pump fed so that's difficult

 

[Best]

I agree. Be careful taking flow & pressure from the outside tap. For a start the outside taps are usually very restricted with flow. Some also have those check valves in them which really reduce the flow as has been said. You should really take your pressure & flow from an open pipe. You could remove the outside tap temporary, for example. After all, your unvented unit will potentially joined to the mains pipe, without any restrictive valves except those supplied with it.