Upgrading water mains to 25mm MDPE, Internal piping 15mm

[Madrab]

An un-vented cylinder should really be serviced once a year.

Prices - that unassailable question - depends where in the country you are really, anywhere between £50 > £100 plus materials if needed, I'd say.

 

[k8581]

Thanks.

I am still not sure if servicing megaflo will resolve my flow rate issue. With 25mm MDPE coming in from street and with pressure over 3 bar (dynamic), I am not sure why my flow rate is below 10 litres per minute?

 

[simond]

This is sadly a prime example of following advice to update/increase the incoming supply pipe diameter typically dispensed on this forum.

There is no way a respondent on this forum would know how much improvement a larger pipe would make, without measuring the flow rate at the road demarcation point first. And this hasn't been done or proposed.

Unfortunately you have wasted your money - I can think of at least 4 customers I have been out to who have read posts on this very forum and been convinced of the merits of upgrading their supply pipe, only to get what one could describe as a marginal improvement, and had to look further afield.

For anyone in doubt, the fact that your static pressure is 3bar does not mean that you will get more flow rate when the incoming pipe is enlarged. You must first ask your local water supplier to measure the flow rate in the street at your isolation point and put it in writing, this will be in litres/minute.

Only then, with this information to hand, will you have the data upon which to justify £1.4K. Alternatively, you will have tacit proof that it isn't worth doing if the flow rate is only 3l/m higher at the pavement connection.



NB: If you have 3bar static I can guarantee an accumulator will resolve the problem, without measuring the incoming flow. This is because with an accumulator you are buffering a large volume of water in your own property at 3bar, rather like having a large charged battery on site. Unfortunately, that will cost about the same again.

 

[k8581]

I think its harsh to say that upgrading mains is waste of money when accumulator costs as much and is more hassles considering the space it occupies and if there are 2 showers or bath taps open at the same time, the accumulator of a decent size runs out in 10-15 mins. So even though i appreciate your views simond, this forum is not accumulator vs mains upgrade. Upgrading mains has one added benefit that the water co will change their bit from lead to MDPE if I change my bit. Also, the flow rate has definitely improved - its just that the output from megaflo doesnt seem to have changed. I have no regrets about upgrading mains and I will strongly recommend it against installing accumulators. If anyone can help based on my existing plumbing, it will be much appreciated. If not, thanks anyways.

 

[Madrab]

Given you are only getting 2 bar from your megaflow, if you have it serviced, one of those service items will be a check on the Megaflow's PRV.
Pressure and flow rate are different things of course, you can have all the pressure in the world but if you have a restriction in the pipe somewhere then flow could be compromised.
That aside, have you always had this issue or is this a problem that has become steadily worse?

 

[St0rmer66]

Well you've already been told to get the Megaflo looked at which you have then ignored. What else do you want? Could be as simple as a blocked inlet gauze on the water section. Not a DIY job as you need to be qualified to work on Unvented components.

 

[k8581]

Thanks Madrab i have always had this issue but i only moved into this house last year. And i have not ignored anything. I am trying to understand the real problem before getting things done. If you cant help its fine - no one is forcing you to.

 

[Agile]

Under Building Regs it should be serviced every year.

Simple service about £55/£65 but if required to open pressure reducing valves the perhaps a bit more. If the valve has never been opened before then it may be jammed or break!

In your case I would take the view there is a fault and probably charge £74/£84.

The pressure should reduce when hot water is taken!

Sometimes the gauges are jammed! You can check that by turning off mains stopcock and turning on hot tap and gauge should fall to zero.

Tony

 

[k8581]

Can someone please confirm what should be the expected average flow rate at internal stop cock with a 25mm MDPE? I know it depends on other factors but a ball park will be helpful.

 

[St0rmer66]

How long is a piece of string?

 

[k8581]

It depends on how much you can see and how far you can think!!!

 

[simond]

I have no regrets about upgrading mains and I will strongly recommend it against installing accumulators.

I merely do this for a day job, so can only defer to your experience and knowledge.

Only one thing bothers me; I would like to query why you are asking such basic questions on this forum if you already know all the answers.

 

[k8581]

I dont know all the answers - but i am a keen student and i like to learn more and reconfirm if my understanding is correct!!

 

[copea]

Can someone please confirm what should be the expected average flow rate at internal stop cock with a 25mm MDPE? I know it depends on other factors but a ball park will be helpful.

I've just done mine today and I was previously getting a maximum of 16lpm on an ancient run of 1/2" galvanized.
I now get 27lpm from the garden tap (through 15mm internal pipe).

Probably not similar setups to allow any meaningful comparison, but shows what is possible.

 

[k8581]

I was told that the megaflo balancing valve has gone rubbish and needs replacing which will improve the flow rate. Is that true?

By the way, one more advantage of replacing my lead with mdpe is that affinity water are going to replace theirs for free now - initially they quoted around £3k.