24l/min: Is there any point upgrading our mains supply?

[ldt]

Hello, long time lurker, first post so go gentle with me.

I have run-down a 50's bungalow which we are planning to extend both sideways and into the loft. This will result in a 3 bed, 1 bath, 1 ensuite and possibly downstairs shower room. Currently there is just the two of us but this will now doubt change in the not too distant future.

At present we don't have any central heating and hot water is provided by a gravity fed cylinder with immersion heater. At some stage a parkray solid fuel fire also heated the cylinder but this has long since been decommissioned.

Incoming mains is 15mm and approx 10m from the supply in the street. Mains pressure is 4.5 - 5.0bar gauge depending upon time of day. I've measured the following flow rates at the closest tap to the incoming mains.

Max flow of 24l/min at 1bar residual mains pressure
22l/m at 2bar
15l/m at 3bar

Hopefully that makes sense..i.e. I opened the tap far enough to drop the measured supply pressure to the values shown and then used a bucket to measure the flow.

Within reason we have a blank canvas as far as heating system and have already had a brand new gas supply layed to the house. A large combi or storage combi appeals for simplicity and cost reasons although I've lurked long enough to hear 'system boiler' being shouted already!

Enough wittering, my question is whether we need to upgrade the mains supply to future proof for our requirements. My gut feel is that although only a tiddly 15mm supply we're actually in a reasonable position already.

Thanks in advance

 

[mehran]

looks ok to me

if space is tight but you want good hot water flow then:
http://www.rinnaiuk.com/2_Products/2_Gas_Water_Heaters/1_Internal/2_26i/1_26i.html would be my vote

 

[Happyplumber]

If you are asking me what i would do personally then with the amount of renovation work you are doing then upgrading the supply with 25mm mdpe as minimum would be an excellent idea and i would definitely do this in my own place

Doing it as part of renovation wont cost much as you will probably a mini digger there anyway for the footing digging a narrow trench all the way to the end of the garden will only take a few hours

Then you wont need to worry about off peak and peak flow rates etc

 

[muggles]

With a bathroom, en suite and shower room I'd be inclined to suggest you go for either a high-output storage combi or an unvented cylinder and system / heat only boiler. The unvented option will give you the best flow rates available for your property and much more available hot water than the storage combi; should you have a situation where both showers and the bath are running at the same time this will prove very useful.

As Happy has said go for a 25mm main minimum, although a 32mm wouldn't cost too much more and is worth considering for maximum performance if you're doing the work anyway.

 

[Agile]

You are really lucky to have such a high mains pressure and already sufficient dynamic flow rate to have an unvented cylinder.

For two people a 937 will be adequate as long as you stagger bath/shower times.

However, my advice is to have a new 32mm pipe laid at min 750mm and a 300 li unvented cylinder. Then you can shower and bath at the same time.

You say its only two people but that may change. Is it likely to change much as that question could affect the sixe of cylinder required. It it were just two adults and two kids then a 210 li cylinder would be adequate until/unless there were two teenage girls ( as they spend hours in the bathrooms! The one here has a basin and mirror in her own room as well as an industrial size sewing machine and a life size stuffed large dog, not actually a stuffed real dog but a manufactured dog with a long red tongue hanging out ).

Tony

 

[ldt]

Its got to be said I hadn't considered the stuffed dog factor

Many thanks for the responses, think I know what needs to be done for a belt and braces approach. Best dig out the shovel.

Are there any other recommended storage boilers the Valliant 937 looks good but the 15l storage capacity seems small?

I've seen a Potterton Promax HE150 installed in a friends new build and the one box idea appears a good compromise between cost and performance vs a system set up to my uneducated eyes.

 

[Happyplumber]

//www.diynot.com/forums/viewtopic.php?t=215837


have look , i think micky is an ex vaillant group engineer,they also own glow worm so i would take is his advice .The veissman kit looks really good too but i have not installed one yet