Un-vented installs

[chris watkins]

Hi All
Have you any idea's why it is that 75% + of all the un-vented hot water installs I go to, are incorrect & do not meet Part G Building reg's (& I have seen a lot in my time) don't get me wrong some are silly things like discharge pipes too long or running up hill but others are down right dangerous. Why is it so difficult to get these right ?????

and how the B***hell do Building Control or NHBS sign them off ??????

 

[Gray0689]

How are the discharge pipes to long??

 

[Mike Jackson]

Building Control haven't got the faintest idea about how they should be installed. They just assume the installer knows what they are doing. They don't even check the installer has a ticket most of the time. Until the unvented equivalent of Ronan Point happens it will stay the same.

 

[mark_mc]

i have a question about a unvented install can you install the 3 bar prv on the incoming mains and at the cylinder just a stopcock and check valve with a safety valve and fo away with the prv at the cylinder.

 

[Mike Jackson]

As long as there are no valves between the cylinder and the expansion relief valve it can be done. As long as you can separate the combination valve into the correct components. It's just as easy to fit a separate PRV on the incoming main though. They're not a lot of money and saves any confusion in future.

 

[tamz]

Like everything else, combination of laziness, ignorance and stupidity. No excuse for any of it.
Building control or NHBC only see the new build stuff and they seem to know or care very little about them.

How are the discharge pipes to long??

Incorrectly sized for the run length.

 

[Gray0689]

i have a question about a unvented install can you install the 3 bar prv on the incoming mains and at the cylinder just a stopcock and check valve with a safety valve and fo away with the prv at the cylinder.

Where are you going to balance the cold

 

[mark_mc]

thats great. cant break the combination valve down but will install a prv on the incoming main and then at the cylinder a valve arrangement in order valve, check valve, pressure relief valve, expansion vessel then to cylinder

 

[mark_mc]

if i install a prv on the incoming main into the house all supplies will be 3 bar no matter what.

 

[Gray0689]

Are you tacking a 22mm mains to cylinder

 

[mark_mc]

?tacking >
there is 22mm to the cylinder if thats what you mean gray mate.

 

[mark_mc]

tacking- taking oh sry im silly.

 

[Gray0689]

Lol yes mate

 

[pobsdad]

Don't UVHW cylinders come with everything you need,nowadays?All set up in the right order in a single module?All the ones I've fitted in the past few years have.And still I see blow offs dropping onto the floor in the middle of a block of flats,so when the t&p valve 'fails',boiling water floods the basement stairwell,blocking the only escape route!
The only 2 options are to cap off the entire hot water supply to the flats,or rout the discharge illegally.With people screaming at you from all sides to do the right thing (for them).Including the Boss,saying "We need this contract,don't upset these people."
So, a prv has to run uphill a few inches.Against your will (not that there will be an official record).

 

[chris watkins]

Hi Gary0689 D1 pipework more than 600mm or D2 wrongly sized.
This is a good one
I had a customer a few month ago who wanted to register the installation we had carried out retrospectively, I had told them they needed a building notice at the time (as we are not a member of a competent persons scheme) & it would cost him around £275.00 after a couple of weeks he phoned his local Building Control to ask how much & what he had to do as it was not on their web site the bloke in there office said whats an un-vented hot water system. My customer said when he turn up he confessed that he did not no if it was good or bad but "as it had not blown-up it was probably OK"

So what chance is there that the Law is being enforced, when the policeman don't even know anything about it. As you say this is not uncommon.

So when those of us follow the rules & put the effort in to do things right (re-newing the HW ticket etc) others just carry on working on these systems with impunity.

Do you thing we will ever see a true licensed plumbing & heating engineer not just for gas work ?????

Depressed Chris W

 

[chris watkins]

Hi Pobsdad
Are you aware that the discharge waste can now be taken into a soil stack under AD Part G 2010 ?
It should give you a few more options but it has to be installed in very particular way (HepVO trap & only push fit plastic to name but a couple)

 

[AWheating]

you need to prove to building control the waste system can carry that temp of water and gain there permission.

nothing straight forward when it comes to these cylinders.

 

[Gray0689]

Hi Gary0689 D1 pipework more than 600mm or D2 wrongly sized.
This is a good one
I had a customer a few month ago who wanted to register the installation we had carried out retrospectively, I had told them they needed a building notice at the time (as we are not a member of a competent persons scheme) & it would cost him around £275.00 after a couple of weeks he phoned his local Building Control to ask how much & what he had to do as it was not on their web site the bloke in there office said whats an un-vented hot water system. My customer said when he turn up he confessed that he did not no if it was good or bad but "as it had not blown-up it was probably OK"

So what chance is there that the Law is being enforced, when the policeman don't even know anything about it. As you say this is not uncommon.

So when those of us follow the rules & put the effort in to do things right (re-newing the HW ticket etc) others just carry on working on these systems with impunity.

Do you thing we will ever see a true licensed plumbing & heating engineer not just for gas work ?????

Depressed Chris W

Is it not 500mm??

 

[chris watkins]

NO,NO now it is 600mm, not done the reassessment yet then Gray ??
& Sorry AW, I teach this sh*t, it is all in the G3 so should not need to prove to building "I don't know what what an un-vent cylinder is", control.

 

[Gray0689]

you need to prove to building control the waste system can carry that temp of water and gain there permission.

nothing straight forward when it comes to these cylinders.

There very straight forward
And has anyone ever failed an unvented course lol I think not

 

[tamz]

Is it not 500mm??

Yes but the 500mm is a guidance figure but keeping to it saves the arguments with the one BC officer who may have read the regs. There should really not be any reason to exceed it.

Do you thing we will ever see a true licensed plumbing & heating engineer not just for gas work ?????

Depressed Chris W

Although i am a great advocate and believer of this, it will never happen, well not in my lifetime anyway. Plumbing and public health is not high up the list of important Parliament discussion (no votes or money in it for them) no matter how much the trade bodies lobby. I hope i'm proved wrong.
Btw i sat my unvented ticket in 1987 and have never resat it but i am still (personally) legal :wink:

 

[tamz]

I teach this sh*t, it is all in the G3 so should not need to prove to building "I don't know what what an un-vent cylinder is", control.

Maybe they should put this shyt in the G3 regs (from the Scottish building standards)

4.9.1 Installation of unvented hot water storage systems
Installation of an unvented hot water storage system should be carried out by
a person with appropriate training and practical experience
:lol:

 

[kirkgas]

Yes but the 500mm is a guidance figure but keeping to it saves the arguments with the one BC officer who may have read the regs. There should really not be any reason to exceed it.


Although i am a great advocate and believer of this, it will never happen, well not in my lifetime anyway. Plumbing and public health is not high up the list of important Parliament discussion (no votes or money in it for them) no matter how much the trade bodies lobby. I hope i'm proved wrong.
Btw i sat my unvented ticket in 1987 and have never resat it but i am still (personally) legal :wink:

1987!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
haha thats why you dont know its changed to a pipe length of 600mm max from T&P to top of tundish, tundish still to be within 500mm horizontally of the cylinder and in the same space/room, gies £200 and i will get you through the reassessment, you are dangerous working on the old regs:lol:

 

[chris watkins]

Sorry tamz
but you are not legal, it is no longer an "evergreen", re acs every 5 years ! (new 2010) as I say now D1 = 600mm that is the Max, building control can not argue with the Law.

Btw spot on with the rest & 1987 me too but was working on un-vent well before that.

 

[kirkgas]

Hi All
Have you any idea's why it is that 75% + of all the un-vented hot water installs I go to, are incorrect & do not meet Part G Building reg's (& I have seen a lot in my time) don't get me wrong some are silly things like discharge pipes too long or running up hill but others are down right dangerous. Why is it so difficult to get these right ?????

and how the B***hell do Building Control or NHBS sign them off ??????

if the install is done by a competant person then they would self certify so BC wont know anything about it

 

[tamz]

1987!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
haha thats why you dont know its changed to a pipe length of 600mm max from T&P to top of tundish, tundish still to be within 500mm horizontally of the cylinder and in the same space/room, gies £200 and i will get you through the reassessment, you are dangerous working on the old regs:lol:

+
I know the regs as well as you do Kirk and i will spend my 200 elsewhere. There is no need for me to spend it on an unvented ticket (G3 is not valid up here as you know so i'll not call it that) when i'm a member of a certain class of persons :wink:

Btw that OF Elan is still cluttering up my garden :lol: I've resisted the temptation to get £15 quid for the HE. I'll drop it off some day :smile:

 

[tamz]

Sorry tamz
but you are not legal, it is no longer an "evergreen", re acs every 5 years ! (new 2010) as I say now D1 = 600mm that is the Max, building control can not argue with the Law.

Btw spot on with the rest & 1987 me too but was working on un-vent well before that.

You rules do not apply up here i'm afraid. I can assure you i am legal with a yearly certificate to prove it.
I know that the max D1 has changed to 600mm. Rules and regs are my hobby after the plumbing (i'm a sad workaholic bstd). There are a few things needing changed with the writing of the unvented regs as they are no longer valid but change will come ...........slowly. An extra 100mm D1 is the least of what needs changed.
What concerns me more is the formality of getting a ticket (any ticket). Pay the money and you have it

 

[tamz]

Btw spot on with the rest & 1987 me too but was working on un-vent well before that.

You'll remember the polystels then :lol:

 

[Mike Jackson]

When I first did my unvented ticket we trained on polystels. We even had one guy fail his unvented course on health and safety grounds. He was leaning over an unvented unit unscrewing the sacrificial anode with the water on and the cylinder under full pressure.

 

[Mike Jackson]

Some years ago I got called out to a flood in a block of sheltered flats. Water was pouring down from the top floor flat. When I got in there someone had swapped the old polystel units which had a 15mm D1 and 22mm D2 for megaflos which had a 22mm D1 at the time and retained the existing discharge pipes. The T&P relief had failed to full bore and the discharge pipework couldn't take the flow. Because of the 22mm D1 it should have been 28mm minimum but when I calculated the resistance it needed to be 35mm. No wonder the 22 couldn't take it. I had to cap off the cold to the unit to make it safe.

When I checked the other 4 flats in the block the next day they had all been installed the same. We had a fun couple of days upgrading all the discharge pipes. That's one of the few times I've actually used the 35mm capacity on my stand bender.