Megaflow cost for installation

[mfarrow]

How far is it from the road to the current incoming point? Did he say what the dynamic pressure is? I.e. with an outside tap open and splurting out 20l/min +, what is the pressure reading then? It needs to be more than a bar ideally.

15mm may be enough, we have 12m of the stuff from street to inside, and can easily cope with a shower and flushed toilet. We have 4-6 bar though depending on time of day.

If your length is similar to ours or less and you upgrade 15-22 internally then I would say crack on.

 

[PullerGas]

Hi Guys, So we got our building works started and first thing we got the pressure bar checked. It goes to 3.5 bar but with 15mm pipe. We have also found that there is no water meter, it is only stop clock at the front of the house.
My builder says there is no need to change the pipe to anything higher than 15mm as pressure is more than enough for megaflow to work. But when insisted, he says at most he can change the pipe to 22mm or any higher till the limits of within the property and will not go until the stop clock.
At the moment, the pipe size from boiler to bathroom is 22mm and from mains/stop clock outside the property is 15mm. Please advise what should we do:

1) Should we still go for megaflow with 15mm pipe, is he right that changing the pipe will not help as pressure is good and bigger pipe will not make any difference.
2) Should we go for megaflow and get the pipe changed atleast within the property (like from front door to the boiler as it will involve no digging, but just picking up floor boards. (He says he still needs to check if the water pipe from outside is drilled into the property or in some other big cast iron pipe which will obviously make things easier for him as he does not need to drill into the foundation to the outside).
3) Should we just cancel the megaflow and go for combi boiler.

A Time Served & fully qualified Plumber & Heating Engineer can check all these things for you, but hey your 'Builder' will have one of them, will he???!!!

 

[dilalio]

There's an element of panic to your posts! Is your builder doing the plumbing and heating works himself or (like most) is he bringing in someone he uses to do it? I would insist you meet with the installer on site and ask him to talk you through what's planned & what your concerns are. This might put your mind at rest. Don't be afraid to ask for verification that he is qualified to do the work.
For the builders we work for (only a couple) we insist on a client meeting.

 

[kaps]

Thank you all for looking at my post, i have tried my best to answer these:
dilalio@ He is a main contractor but he does the plumbing work himself but all other works he has sub contractors. like for electric there is a different guy, for boiler there is a different guy who will give us gas certificate. So far i have not seen him taking shortcuts or giving us any wrong recommendation.

mfarrow@ thanks i will ask him to check the dynamic pressure by switching on one tap, could it be any tap ? as there is no tap outside of the property. Also as you have mentioned that it will be enough for a toilet and bath, but do you think it is still better what we can get from combi ? initially we thought of going to combi but everyone guided us to megaflo as we will get good pressure and hot water if someone is working in kitchen and at same time someone is taking bath. Do you think this is achievable if we get the pipe replaced internally ?

May be if we can get him pipe changed internally and then call water company to put up a meter and then call someone to do the digging outside and replace the pipe from meter to the immediate entry point of the pipe to the house, it will save us taking up all the floorboards etc. atleast internal work would be ticked off.


Pullergar@ We dont know to be honest, he said he will do the plumbing and he has someone for boiler. Now if I know the right questions to ask, I can keep him doing the right job. Boiler guy will definitely be qualified as he will give us the gas certificate.

 

[PullerGas]

Thank you all for looking at my post, i have tried my best to answer these:
dilalio@ He is a main contractor but he does the plumbing work himself but all other works he has sub contractors. like for electric there is a different guy, for boiler there is a different guy who will give us gas certificate. So far i have not seen him taking shortcuts or giving us any wrong recommendation.

mfarrow@ thanks i will ask him to check the dynamic pressure by switching on one tap, could it be any tap ? as there is no tap outside of the property. Also as you have mentioned that it will be enough for a toilet and bath, but do you think it is still better what we can get from combi ? initially we thought of going to combi but everyone guided us to megaflo as we will get good pressure and hot water if someone is working in kitchen and at same time someone is taking bath. Do you think this is achievable if we get the pipe replaced internally ?

May be if we can get him pipe changed internally and then call water company to put up a meter and then call someone to do the digging outside and replace the pipe from meter to the immediate entry point of the pipe to the house, it will save us taking up all the floorboards etc. atleast internal work would be ticked off.


Pullergar@ We dont know to be honest, he said he will do the plumbing and he has someone for boiler. Now if I know the right questions to ask, I can keep him doing the right job. Boiler guy will definitely be qualified as he will give us the gas certificate.

Wouldn't bet on any of it!!! Sounds a right cowboy.

 

[mfarrow]

mfarrow@ thanks i will ask him to check the dynamic pressure by switching on one tap, could it be any tap ? as there is no tap outside of the property. Also as you have mentioned that it will be enough for a toilet and bath, but do you think it is still better what we can get from combi ? initially we thought of going to combi but everyone guided us to megaflo as we will get good pressure and hot water if someone is working in kitchen and at same time someone is taking bath. Do you think this is achievable if we get the pipe replaced internally ?

May be if we can get him pipe changed internally and then call water company to put up a meter and then call someone to do the digging outside and replace the pipe from meter to the immediate entry point of the pipe to the house, it will save us taking up all the floorboards etc. atleast internal work would be ticked off.

A kitchen sink will be OK, assuming you've not got an aerator on the end, but these can usually be unscrewed.

The main reason for the check is to, in theory, validate the pressure drop: 10m of 15mm pipe will lose you 1.9bar @ 30 l/min. Whereas 20m length with same parameters loses 3.8bar, hence I asked about distance from boundary. See http://www.pressure-drop.com/Online-Calculator/ .

The main disadvantage of a combi is that the heat exchanger loses lots of pressure compared to a cylinder, which is effectively a large pipe, so loses very little pressure.

If it doesnt work out then of course you can do the outside bit afterwards.

We moved the incoming 15mm pipe at ours back by 4m when we had a downstairs toilet put in and had to dig the passage out anyway. Also put in 22mm from new incoming position. I fitted a pressure gauge permanently and we struggle to get less than 2 bar now whilst wasting lots of water from 3 open taps.

 

[oilboffin]

I smell John Wayne you'll be sorry and you could be prosecuted.