G
Gray0689
Because its not very energy efficient to do so
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View the thread, titled "speed fit on secondary return" which is posted in UK Plumbers Forums on UK Plumbers Forums.
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.
G
Gray0689
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
G
Gray0689
Correct but still it don't need to be running 24/7 in domestic
G
Gray0689
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
I say potato and you say potatoe ... Let's call the whole thing off 🙂
Why you not batman on here howsie ? Come on, bring out your alter ego 🙂
S
sheff paul
Thanks lads I think this thread has run its course,ended up putting copper job done
Ok Brucie babes 🙂
V
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!
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!
M
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.
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.
Last edited by a moderator:
V
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?
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?
Like in my mums house 🙂
Higher pressure in invented ? CH water isolated from mains ? If secondary return leaks its constant leak ?
V
vern
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....
M
Masood
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!
V
vern
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!
V
vern
100% agree...very rare but seen it happen!
If the manufactures say 'No' then surely no it is?
But a properly soldered joint?
Clearly you have never been in or worked in a nursing or old peoples home, heating and hot water 24/7 365 🙂
V
vern
Because you can't on hot water due to legionaries, nursing homes are under intense regulation! As are other commercial applications......
M
Masood
No mate, they don't. The manufacturers say their product must not be used for secondary returns. No mention of hours per day or anything else. Simply no. It's in black and white on their websites. You can choose to ignore it, but pretending that they allow it under certain circumstances is just wishful thinking.
Technically plasticiser will leach out of system where water is always changing ,hence more brittle (less spring back to keep things sealed)
Sealed circuit (ie-Boiler) , plasticiser cannot escape gets re-circulated
( PURE Theory no experiece with plastic plumbing--)
Loss of plasticiser and enbrittlement == fact
Trade offs a) How hot
b) How much water thru system
c) How many years of life
d) How many hours a day pump runs
e) Price of install
Life whole system needs to last -vs- water thru system for effect to happen
Copper rules !
Sealed circuit (ie-Boiler) , plasticiser cannot escape gets re-circulated
( PURE Theory no experiece with plastic plumbing--)
Loss of plasticiser and enbrittlement == fact
Trade offs a) How hot
b) How much water thru system
c) How many years of life
d) How many hours a day pump runs
e) Price of install
Life whole system needs to last -vs- water thru system for effect to happen
Copper rules !
load of ole twaddle I bet you don"t even understand half of what you just posted
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