Before the possible Combi Arrives

[lsearson]

hi all,

I've had enough of the indirect system i have with a very old Glow worm boiler, so moving into the 21st century i think its time for a combi as its only myself and my partner in the house. BUT before i start doing anything to drastic, is there anything i really need to do or look into before i get the ball rolling.

i.e. i am in a town house ( 3 Storey), so do i need to confirm water pressure, rules and building regs, what direction do i need the flue etc...

i must add i am looking at the Condensing HE boiler range, possibly potterton,

any help would be greatly apperciated

 

[gas4you]

You will need quite good mains inlet pressure if you have any baths or en-suites on top floor.

What ever size combi you go for, forget the 24Kw, bear in mind that it will only adequately supply one hot outlet at a time

 

[lsearson]

good point, i must add i have the bathroom on the top floor along with 3 rads on each floor. Also i currently have an electric shower plumbed in is it worth keeping that or plumbing that into the combi also

 

[gas4you]

rads will be no problem on top floor.

Debatable whether to keep electric shower, probably cheaper to run off combi, but electric will give independent back up. Is this your only shower or do you have others as well?

 

[lsearson]

no thats the only shower, and the only bathroom, and kitchen is on ground floor, nothing but 3 rads on 2nd floor

 

[gas4you]

If you keep to electric then using other hot taps shouldn't affect the temp. Totally personal opinion would be to fit a quality thermostatic shower off combi if you have v good mains pressure, but this would incur greater cost and disruption/amendment to pipe work.

Your home, your budget, your decision. If you have mainly showers and less baths I do not see the need to go for 37 or 40Kw combi, but again its down to your preference

 

[lsearson]

i want to spend about 1K on the boiler and im going to do all the pipework myself, we mainly have showers, so am i still looking at the 37 or 40kw boiler. also is it worth me measuring the pressure of mains on the 3rd floor, i was going to measure this out of the mains to the current f+e tank

 

[gas4you]

Can do, but you need to measure working pressure and flow rate. Standing pressure usually does not mean much other than water is there There is some guidline somewhere that states the pressure will drop by about 0.25 bar per storey. perhaps someone else can clarify this.

 

[lsearson]

so do you think i need to worry about the pressure or flow of the mains coming to the house, if i go for a 37 or 40kw boiler, and just keep the shower electric, also am i forgetting any other important stuff

thanks

 

[gas4you]

Most modern combi's will work down to about 0.5 bar inlet pressure, but to be successfule I would like to see around 2 bar.

I would defintley check your incoming mains pressure and then pressure/flow on top floor first

 

[Agile]

so do you think i need to worry about the pressure or flow of the mains coming to the house, if i go for a 37 or 40kw boiler, and just keep the shower electric, also am i forgetting any other important stuff

thanks

Its not just a question of "do you need to worry" !

Its a simple fact that a combi relies on the mains water supply for delivering hot water. You need at least 20 li/min open pipe.

If its insufficient then you will have wasted you money on a boiler you cannot use.

If you were paying for all this free professional advice then would you then still want to ignore it?

Tony

 

[lsearson]

hi

so after Tony's response, i suppose i do need to worry about the pressure/flow.

If im going to measure this properly how do you suggest i do this, i want to measure the flow and pressure on top floor as well as ground,

any ideas

 

[gas4you]

Well I certainly wouldn't worry about it but certainly have it checked. Even the largest combi will only give aroung 14/16 l/min of hot water, mid sized usually around 12. If you can fill a milk bottle in around 2 or 3 secs on top floor then don't worry.

From a tap I mean, not you personally

 

[lsearson]

thanks gas 4you,

but from what source is best, shall i get it from the mains to my f+e tank, or shall i run a hosepipe up the side of the house from the mains and measure that way, or any other ideas accepted

 

[gas4you]

I assume your f&e is above the 3rd floor in which case this would be perfect as it will give a slightly lower result than on the 3rd floor and you will be on the right side of any results.

If it is easier you can run a hosepipe up but make sure the tap you come off is fully open.