Boiler advise needed please

[higgster]

I have an old vented system and want to knock out airing cupboard so we gain all that space for the bathroom. the new installation will be going in garage so space no problem. Really wanted to fit megaflo or similar (4 bed house with 2 showers etc) but only have 16lpm flow coming in to the propery via 15mm pipe. Would a combi such as vaillant 837 be suitable for this?? there could be a time when we run 2 showers, will the 15.2 lpm be adequate?? any thoughts / help greatly recieved.[/b]

 

[heatingman]

whatever option you go for get the mains upgraded to give an adequate, continuous, un-interrupted supply of water

 

[bengasman]

16 l/min would leave you 8 l/min for each shower, it could work, but you will have to jump a bit to get wet, and that is providing nobody opens another tap of flushes a loo. You are really looking at upgrading the incoming mains first.

 

[higgster]

Thanks for the comments, presumably upgrading the mains means digging in a larger diameter pipe from the mains at the foot of the driveway. sounds expensive?? would this then mean that I could go for a megaflo type system?? if I stuck to the combi idea Would the 16lpm give a good shower whilst another hot tap is running say in the kitchen??

 

[doitall]

Before you do anything, you need to get the pressure of the mains at peak and off peak times.

16Ltr/m is not bad, but by the time it comes out of the combi will be much lower.

If you had good mains pressure, you could up-size the pipe (favorite) or have an accumulator stood in the garage next to the unvented cylinder.

You could have a large storage tank and whole house pump in the garage, as another option.

It's gonna cost whichever you go so you should be looking at the best system for your money, and that is down to mains pressure.

A new mains you could always install yourself if you fancy a bit of exercise, and get the water company to make the connection.

 

[bengasman]

16 l/min would leave you 8 l/min for each shower, it could work, but you will have to jump a bit to get wet, and that is providing nobody opens another tap of flushes a loo.

This will be the same for a combi as for an unvented cylinder; wherever it goes, it depends on the available flow capacity. You either have to upgrade the mains water supply, or go back to a vented cylinder and cws.

 

[higgster]

OK, I have just re-checked the flow a little more accuratley and it appears I have around 23LPM with a pressure of 2.6 Bar. 10:00 so I guess thats not peak time. working lates so cant check in the evening untill thursday.
Am really stuck now as I need to get on with installing the new kitchen but need to get the heating/plumbing sorted first and want to make the correct choice as it could prove to be an expensive mistake if I don't get it right first time!
If the 23lpm is correct then would this be enough for unvented system??

 

[higgster]

Forgot to mention that I have a 22mm supply, this goes to 15mm directly after the stopcock so presumably if I went 22mm across the system the flow rate might be a little higher??