speed fit on secondary return

[sheff paul]

Just changing some dodgy waste pipes on a dubious bathroom job installed by a DIYer putting speed fit in as some has already been fitted in for some time before ,then notice's the unvented has a secondary return fitted.Do I finish it off in plastic and get done for lunch,or do I rip it all out and get home late,this job is a favour money free one.Has anyone fitted platic on a secondary return set up,yes I know you should not use it.

 

[sheff paul]

how much was it 15mm and 22mm

about 4 mts of 15mm

 

[SafeGasInstall]

I was asking for the price ?

 

[Gray0689]

I was asking for the price ?

£1.10 a metre

 

[kimbo]

The hotter the pipe gets the less pressure it could take so If you were really unlucky and your pressure reducing valve failed and your thermostat failed I think you could very easily blow the pipe like you see has happened on some heating systems.

 

[Howsie]

its not continuously operated with a timer and a stat you would never run a secondary return 24/7 it'll run at a lower temperature than central heating and probably for the same length of time in the winter

Why not?

 

[Gray0689]

Why not?

Because its not very energy efficient to do so

 

[Howsie]

Because its not very energy efficient to do so

Really depends on the customers requirements. If they have a 24/7 requirement and the pipes are lagged properly then I can't see the problem.

 

[nicro3]

The whole point of having a HWSR is so hot water is instant with no deadleg and waiting, also negates legionella.

 

[Gray0689]

Really depends on the customers requirements. If they have a 24/7 requirement and the pipes are lagged properly then I can't see the problem.

We are talking about a domestic setting
Not commercial or industrial
There won't be a 24/7 requirement so it would be inefficient to have running all the time

 

[Gray0689]

The whole point of having a HWSR is so hot water is instant with no deadleg and waiting, also negates legionella.

Correct but still it don't need to be running 24/7 in domestic

 

[Howsie]

Perhaps but perhaps not.

The point being that as an installer you have to cater for the potential use and its not unreasonable to assume that a HH may want instant hot water on some occasions 24/7.

 

[Gray0689]

Perhaps but perhaps not.

The point being that as an installer you have to cater for the potential use and its not unreasonable to assume that a HH may want instant hot water on some occasions 24/7.

You do it your way and ill do it my way
Simple
The way fuel is going the least amount that can be used the better and more cost effective

 

[dancinplumba]

I say potato and you say potatoe ... Let's call the whole thing off

 

[dancinplumba]

Why you not batman on here howsie ? Come on, bring out your alter ego

 

[sheff paul]

I say potato and you say potatoe ... Let's call the whole thing off

Thanks lads I think this thread has run its course,ended up putting copper job done

 

[Howsie]

Why you not batman on here howsie ? Come on, bring out your alter ego

Don't tell everyone.

 

[dancinplumba]

Don't tell everyone.

Ok Brucie babes

 

[vern]

Right I will just tell you why not to use plastic on secondary returns.....

This came from a big chief at Hep20 owned by Wavin......we kept going to water leaks in a nursing home when the pipe had failed, so lads on call just banged a meter with a couple of sockets job done, but sadly, it kept happening, I got called out and noticed it was only the secondary return, every other pipe installed in the same place and the same time, same materials etc was ok......

i made a call, and it basically comes down to the pipes composition, it is not continually rated for heat 24/7 like Mike pointed out, why? Because of the memory effect it needs to cool down, he quoted for every hour on, it should be off an hour, obviously not intermittently, but if on 12 hours it should be off 12 hours in total......as the plastic heats it changes state, and only relaxes and goes back to the state when cool, if it does not get back to its original state, it becomes more brittle and will fail eventually.....just like bending a shatter proof ruler, it won't break straight away, bit it will turn white, where the stress is, then fail at that point, if it is subjected to more stress over time.

As some have pointed out, in domestic applications where the pump is timed it should not be a problem, unless its left on constant......be warned insurance companies are getting wise to water damaged claims, we had the one in a new build, loss adjuster with the aid of his plumber, pointed out it was not fit for purpose, they refused to pay out!

 

[Masood]

Vern has it spot on. If you use pushfit on a secondary return, and get a problem, the manufacturer immediately has a get-out from their warranty. Your insurance company will also refuse to pay out, because, as the manufacturer has expressly forbidden its use, you have used materials that are not fit for purpose.

No amount of arguing about timers and stats and duty cycles will change the fact that the manufacturer clearly states not to use their product in this way. Whatever the underlying reason for that statement, its existence means that you would be 100% liable for any claim.

 

[vern]

I should make a point too said new build was a 6 bed, oak doors, floors etc, very nice only around 3 year old, they guy left everything on constant and used the room stats etc, hot water and secondary return was on 24/7! Hence the failure, luckily we did not do the install, we got involved with the WB 40 CDi which was under gassed and no ABV.....Anyhow it failed when they were at a party, it brought down ceilings, poured everywhere, remember this is mains pressure hot water fed via a 300 l Megaflo, it just kept leaking out!

This job is still going on legally, but the twist the owner supplied ALL the materials, the installer just used what he was given, but I feel this is no excuse, after all maybe it is not as well known about using plastic on seconday returns but using plastic on gas because the owner supplied the materials would be no defence either!

Regards the nursing home, it was always the 15 mm secondary return that failed, not the draw offs, which is essentially the same pipe run, only thing I put it down to was when we ripped it all out, all the runs were 22 mm with just 15 mm stabbings for sentinel points in copper, I assume the 22 mm was slightly tougher or different wall thickness?

 

[SimonG]

So if central heating was on 24/7 365 days a year?

 

[dancinplumba]

So if central heating was on 24/7 365 days a year?

Like in my mums house

 

[SimonG]

Nursing homes etc. Or is that exempt as it's not oxygenated in the central heating.

 

[dancinplumba]

Higher pressure in invented ? CH water isolated from mains ? If secondary return leaks its constant leak ?

 

[vern]

Nursing homes etc. Or is that exempt as it's not oxygenated in the central heating.

I work in loads Simon, and yes they are on a lot, but not 24 hours everyday, maybe the fresh water has an effect too, all I know is what I have seen, not good....

 

[SimonG]

The one round the corner from me do. It's continuous. It's like a bloody oven in there. 9 rooms and 4 flats.

 

[markfxy]

Load of nonsense I've used hep on returns for years with no problems its a lower temp than central heating and the pressure is 3 bar max, another bit of scaremongering about plastic yet again!

 

[Masood]

Load of nonsense I've used hep on returns for years with no problems its a lower temp than central heating and the pressure is 3 bar max, another bit of scaremongering about plastic yet again!

Well... No problems until one occurs! Not suggesting that there will be a problem, of course, but if one does, no manufacturer will honour the warranty, and your insurance will be void. It's like any regulation or precaution - it's not there to cover the 99.999% of situations where nothing goes wrong, but the 0.001% of the time when something does...

You make your choice and take the consequences - you're a braver man than me!

 

[vern]

Load of nonsense I've used hep on returns for years with no problems its a lower temp than central heating and the pressure is 3 bar max, another bit of scaremongering about plastic yet again!

Aww maybe I am wrong then, and the manufactures are too, hence why they dont endorse it for this application, must have been the ammonia essence that caused multiple pipe failures......the returns do have to be on 24 hrs a day for this to occur.

I don't hate plastic pipes, indeed it has it merits in some circumstances, but copper all day long for Vern!

 

[vern]

Well... No problems until one occurs! Not suggesting that there will be a problem, of course, but if one does, no manufacturer will honour the warranty, and your insurance will be void. It's like any regulation or precaution - it's not there to cover the 99.999% of situations where nothing goes wrong, but the 0.001% of the time when something does...

You make your choice and take the consequences - you're a braver man than me!

100% agree...very rare but seen it happen!