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General Plumbing and Gasfitting Talk => Ask Plumbers (Public) => Plumbing => Q & A - Hot Water Cylinders => Topic started by: hawkeye on August 23, 2010, 05:54:26 PM

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Title: Mains/Low pressure query
Post by: hawkeye on August 23, 2010, 05:54:26 PM
Hi there,hoping someone can help me here.I am thinking of using a Mains pressure HWC instead of the existing Low pressure HWC,to increase pressure i intend to fit a Pressure Relief Valve (76 kpa) to the existing roof vent which is about 4 meters above the base of the cylinder,by adjusting the feed valve i should be able to operate at about 100 kpa which hopefully will give a much better shower performance than the existing.Thoughts anyone?
Title: Re: Mains/Low pressure query
Post by: Plumber on August 24, 2010, 07:08:29 AM
Most low pressure Cylinders are rated at 76 kpa (about 7.6 meters), should be on a sticker next to manufacturer and model. If you add more then what the HWC can handle you will cause damage to the casing as the weld can not handle more then the specified pressure long term, also if new, your Cylinder warranty will become invalid so you must be carefull. There are a few ways to increase your pressure, installing the correct valve is one way. I'm sure a registered plumber will be able to advise the correct method after a site visit.  ;)

plumber
Title: Re: Mains/Low pressure query
Post by: hawkeye on August 24, 2010, 07:40:46 AM
Thanks for that,I am considering using a Mains pressure HWC so I can raise the pressure higher than the normal "low" pressure,but below that of Mains pressure.I have access to a free mains pressure cylinder so it seems an economical way of increasing shower performance without spending much.I really just want to know if the shower will improve much?
Title: Re: Mains/Low pressure query
Post by: Wills on August 25, 2010, 01:21:16 AM
Is this a storage tank in the roof hooked up to a wetback setup?
Title: Re: Mains/Low pressure query
Post by: spud on August 25, 2010, 07:56:50 AM
I dont think its really a good idea to be giving people advice on how to install their own hot water systems, If this is a wetback system and you put a relief valve on top for example and there is an explosion after advice that is given on this site Im not sure what the repurcussions would be. I know the PGDB would look at it very closely in terms of court action. I dont think there is anything to gain from this forum and Im not impressed with having my previous post on this topic deleted.
Title: Re: Mains/Low pressure query
Post by: spud on August 25, 2010, 07:59:00 AM
Obviously, if youre putting in a mains pressure cylinder you wouldnt be hooking a wetback back into it, but a relief valve above the roof in frost areas isnt a good idea either. All these factors need to be taken into account when giving advice
Title: Re: Mains/Low pressure query
Post by: robbo on August 25, 2010, 08:47:18 AM
hi guys, it is a very good idea to share information and helpfull advive to other tradesmen but i really don`t support giving free info to the wider public. Us tradesmen are in the trades to make a living and don`t get paid for giving advise or trade secrets. Our knowledge of our trades has been a long process so we should not give it away freely. Perhaps we need a seperate tab on this forum for tradesmen only so we can share info amounst ourselves,just a thought. Of course if anyone wants to share info it is up to them as we know it is not a good idea for the untrained to atempt their own plumbing. Don`t get me wrong this site is great for tradesmen who have something to say, but giving out info to the wider public so they can do our work is a bit dumb, try getting free info from other professionals and see how far you get, just my opinion but food for thought,cheers.
Title: Re: Mains/Low pressure query
Post by: hawkeye on August 25, 2010, 12:31:39 PM
Hi Wills,to answer your question,no, there isnt a header tank or wetback involved.It is an equal low pressure system with 2 feed valves (H & C).No danger of frost as it is on the coast in Northland.Thanks for your interest.
Title: Re: Mains/Low pressure query
Post by: Plumber on August 25, 2010, 02:57:54 PM
Hi Robbo,

I dont disagree with you and would like to share a quote from Charles Spurgeon "True wisdom is to know how to share knowledge". That's what it comes down to. No reason getting upset and thinking you are providing "free info" to the public. Your trade is far more complex then that.

I think your Idea is great and will create an ask plumbers zone only for trade and junior members this area can continue to be used by the public. Thanks for your suggestions!  ;)

Plumber
Title: Re: Mains/Low pressure query
Post by: robbo on August 25, 2010, 07:07:26 PM
hi plumber, Knowledge can be communicated but not wisdom.
- Hermann Hesse
cheers
Title: Re: Mains/Low pressure query
Post by: Plumber on August 25, 2010, 07:19:18 PM
 :D How true that is!
Title: Re: Mains/Low pressure query
Post by: Edbear on September 04, 2010, 07:39:01 PM
Shame that. I've gone and collected all this wisdom, you see, and nobody seems to want it...  ::) It's lying around the place...  ;D