is 15mm cold water ok for megaflo?

[bluesky]

first of all i never installed megaflo although i have passed the course, we are going to install a 300L megaflo, totally 5 shower in this HMO, i am going to connect balanced cold water after the pressure reducing valve, at the moment the water pressure is about 1.5bar in the house, do you guys think the 15mm is ok for the 5 showers?

Shall i use 22mm pipe from the inlet to cylinder?

cheers in advance!

 

[Gray0689]

No chance and 1.5bar is not enough pressure either

This is basic stuff mate if you don't know this you should not be even thinking about this job

 

[ecowarm]

15mm and 5 showers? 1.5bar?

 

[ecowarm]

When I did my unvented course I had to Prove I was a Plumber, I had to take in copies of my C&G etc.

 

[bluesky]

Hi guys, i know that i seriously lack the knowledge of plumbing, you know it is difficult to get jobs at the moment and for this job i have tried hard and dont want to give up, how much pressure can be enough? what i can do to correct the problem?

thanks a lot,

 

[ecowarm]

I should start fitting bathrooms etc. and leave jobs like this to the professionals

 

[Gray0689]

Hi guys, i know that i seriously lack the knowledge of plumbing, you know it is difficult to get jobs at the moment and for this job i have tried hard and dont want to give up, how much pressure can be enough? what i can do to correct the problem?

thanks a lot,

If your qualified you tell us
Come on if you have an unvented ticket look in your book
Or look on instructions

 

[Davinder]

OK, I think everybody deserves a break but I highly recommend you go through your training manuals again.

Or a least use this:
http://www.heatraesadia.com/docs/Megaflo_eco_Specification_brochure.pdf

Using a 15mm pipe to feed 5 showers (not a good idea).

 

[bluesky]

thanks for reminding me, i believe they told me in the course, will find the notes, silly me, cheers anyway

 

[tamz]

Tell the punter they will need to get the supply upgraded. If they can afford a 5 bathroom house then they can afford a better water supply
You would just about get away with it on a one bath house but it would still be below its potential.
If they won't go for an upgraded supply kick it into touch.

 

[Davinder]

I would try to increase the pressure as well, using a break tank and a pump (1.5 isn't enough)

plus at that pressure I would check the flow rate as well.

P.S. What’s 'HMO'?

 

[Gray0689]

Why don't you get someone in who knows what there doing to help you then you will learn for next time

 

[ecowarm]

I would try to increase the pressure as well, using a break tank and a pump (1.5 isn't enough)

plus at that pressure I would check the flow rate as well.

P.S. What’s 'HMO'?

Houses with multiple occupancy

 

[kirkgas]

When I did my unvented course I had to Prove I was a Plumber, I had to take in copies of my C&G etc.

even with plumbing quals some guys dont know how to read MI's, so the first port of call is the MI then training notes to see minimum requirements, and im sure the MI will say 22mm supply and quote a minimum pressure and flow, there are tons of plumbers who dont know the basic theory behind their job, not just the new starts

 

[ecowarm]

if you have gas ACS you are allowed to sit unvented

I agree but does having ACS mean you are experienced in plumbing and heating? from some of the people posting on this forum I think not, I really think the whole system of apprentices/ trainees and fast track training schools needs to be looked at.

 

[Gray0689]

I agree I've seen boys do fast track and great plumbers seem boys do 4 years apprentice and realy have no clue what there doing IMHO
I think your only as good as you want to be whether fast track or apprentice it's on the quality of peaple you learn from I think fast track is fine if you continue to learn after you get the qualification don't think you can jump in to working for yourself we learn somthing everyday in this job but you have to have the passion to learn yourself without being told what to do common sense is one of the biggest things and getting off your backside as nothing gets handed to plumbers IMO

 

[secret squirrel]

I agree I've seen boys do fast track and great plumbers seem boys do 4 years apprentice and realy have no clue what there doing IMHO
I think your only as good as you want to be whether fast track or apprentice it's on the quality of peaple you learn from I think fast track is fine if you continue to learn after you get the qualification don't think you can jump in to working for yourself we learn somthing everyday in this job but you have to have the passion to learn yourself without being told what to do common sense is one of the biggest things and getting off your backside as nothing gets handed to plumbers IMO

I totally agree with the common sense aspect of your reply and also learning something new every day. Part of the problem is that customers want cheap most of the time and if your short of work the tendancy (right or wrong) is to do the job cheaply.

Then the issue is that the plumber feels cheated and that they are working for nothing and start to take short cuts and perhaps rushes. Also the customer isn't honest with us, deliberately deceptive or just misguided. You give a genuine quote to replace a radiator but you don't check the others are working beforehand. Before you know it your £250 incl parts is well short of the mark because your sorting out a bad system for free or end up arguing with the customer.

I think as plumbers we become jaded, fast trackers tend (I think) to get caught in a trap. You trust what the customer tells you, don't look far enough into the job, don't see all the pitfalls and don't really see all the job entails, worry about where the next job is coming from and therefore you don't want to turn anything down. This is the one of the advantages that working for 4 years with an old hand can show you.

There's no doubt in my mind that the originator of this post is well aware and has serious doubts about this but when you start out it isn't as easy as just walking away........ BUT it does get easier.......

 

[mark_mc]

installed an ailbon ultrasteel in a house in dublin. the incoming pressure was only 1 bar and the flow rate was crap. so i installed two break tanks in the loft and a dab booster silent pump and pumped the supply to the unvented cylinder, worked a treat, great pressure 5 bar from the pump and then reduced down at PRV to 3 bar and then balanced supply for cold, flow rates are around 30+ litres a minute.

could work for you, but if you were considered putting an unvented cylinder in with 1.5bar pressure, you may have been sleeping through your unvented course lol. good luck anyway.

 

[GQuigley67]

is the pressure 1.5bar after the pressure reducing valve ?? what is the pressure before that ?? If your that inexperienced then I hope you know your limitations, I would suggest finding a more experienced guy you can get to help you out on big jobs.

Re-Read your post, i read it wrongly lol they will need to get their mains upgraded if they only have 1.5bar !

 

[AWheating]

first of all i never installed megaflo although i have passed the course, we are going to install a 300L megaflo, totally 5 shower in this HMO, i am going to connect balanced cold water after the pressure reducing valve, at the moment the water pressure is about 1.5bar in the house, do you guys think the 15mm is ok for the 5 showers?

Shall i use 22mm pipe from the inlet to cylinder?

cheers in advance!

what is the cold mains flow rate?

You really need to know the flow rate in litres per min to have a full idea of what problems you need to over come( flow rate can effect performance more than pressure). For example if you had 1.5bar and 20 litres per min flow rate according to the megaflow manual you will have a max of 19litres per min flow rate on the hot. Now remembering that this flow rate will be shared with an cold usage more than a couple of mixer valves on at the same time and you will have problems. Having 3 bar of pressure instead on 1.5 wont make much of a difference unless the flow rates higher.

 

[Gray0689]

1.5 bar on 15mm pipe won't meet the flow rate

 

[AlexGas]

You might need to start from scratch here i.e. calculate your hot and cold water pipe sizing for this property.