It's only illegal if you actually do it mate. My comment about t l v was tongue in cheek because the forum is absurd. We shouldn't be encouraging people to do their own plumbing or giving any kind of advice on how to.

dont get me wrong A1 - I wasnt having a go at you, i agree with you

i realised you were taking the mickey - sometimes some things get lost in translation especially through text

and you're right - there could be any multitude of problems causing the OP's outlined situation that should be checked prior to any costly work being done

Hi I'm here to put a washer on your orb but I've noticed you don't have a tempering valve. I'm going to have to put one in and it's going to cost you $400.

But I don't have $400

I'm sorry but I legally have to install one. Go get your cheque book.

Get out of my house

I'm sorry but I'm installing a tempering valve.

I don't want one get out.

I'm putting one in get out of my way

I'm calling the police

stil LMAO - GOLD!!

Spectacular - I didn't realsie that there were so many precious / anxious plumbers out there.
I'm after information so that I am informed when I engage a certified plumber to make the remedial work.
The certified plumber I engaged to install my new fire, wetback & new hot water cylinder followed the standards but didn't get the system working anywhere near to my satisfaction.
They made a crap job of installing the flue surround plate at the ceiling - cutting into the ornate cornice........I was totally pissed off.
Anyway enough said, here's my stats;

6.3m head from ajax to open vent - looks like I can get this increased a further 1.5m
flow rate measured from the bath tap - 76mL/s, I ran a 2L bottle, it filled in 26.41 secs.

What would a real plumber recommend in this situation?

1. Increase the open vent pipe to 7.6m.
2. Increase the pipe between HW cylinder & bathroom?
3. Booster pump?

Craig

Craig if those figures are correct then I would suggest you have issues with either the pipe - ie galv - or the pipework - ie too many bends/tees etc

could be a partial blockage somewhere?

may be easy to run dedicated line to shower/bath?

access to pipes?

lots of variables

on a low pressure system a bath should have 3/4"-20mm dia pipe as a rule of thumb, having said that 1/2" would be fine if only a short distance pipe run

for every 90deg bend (unless swept bend) or tee it is roughly equivelent in 5m worth of pipe friction, ie if water had to travel through 4 90deg fittings - bends/tees - thats the same as adding 20m of pipe length and associated pressure/flow losses due to pipe friction

I dont believe you NEED to increase vent height if prv is set right you should be fine in that regard to available pressure


I think you need to get somebody there to check it all out - let them make a judgement call - may just be easier and more cost effective to put in hot water booster pump

Ha ha too right! Gotta love those informed customers who tell you how to do your job before you even start