Plumbers NZ is New Zealand's largest online plumbing, gas and drainage resource. Plumbing exam help, plumbing news, directory and free quotes.

Author Topic: Water Pressure - Few questions  (Read 8725 times)

0 Members and 1 Guest are viewing this topic.

Offline WanaGo

  • Newbie
  • *
  • Posts: 3
  • Karma: +0/-0
Water Pressure - Few questions
« on: February 27, 2011, 10:09:05 PM »
Hello,

I have done a bit of reading on this site and others, however would like to put my questions in one place and hopefully someone can set me straight.
Thanks in advance.

We just purchased a 1978 house that has a new low pressure hot water cylinder. These are the details from the building report. "Peter Cocks Ltd, 2009, 180L Low Pressure Cylinder".
I can not remember the setup in the house exactly. We dont take possession for another month.
The hot water cylinder is located on the ground floor, and the shower is on the 2nd floor. The ground floor is concrete floor, and the 2nd floor is also concrete. The shower pressure is rather poor. It has those 'Topless' shower fittings. The show head is one of those typical topless ones with the black knob on it, and the mixer from memory is one that rotates 360 degrees (sorry I cant visualise it). We will no doubt change these to a new mixer and shower head on a rail (the appropriate type for the pressure obviously).

Basically I just want to collect information to make an informed decision when we move in and determine what we want to change.

Since the hot water cylinder is new, I hope there is scope to increase the pipe above the roof and then crank the valve up a bit, else install one of those pressure releif valves which I have read on here about, however I am not sure if they are suitable.
The house is in Invercargill - so cold in winter... Since its concrete floor, I assume the only option for that pressue relief valve is above the roof?, but since its cold here in winter will it freeze up and maybe the cylinder go - kaboom...?

I am not sure what the options are or what is best.
I am happy to get a plumber over to have a look and give a recommendation, however any input people can give here will let me be better informed for when they do come.

Kind Regards
J

Linkback: https://www.plumbers.nz/q-and-a-hot-water-cylinders/44/water-pressure-few-questions/590/

Offline WanaGo

  • Newbie
  • *
  • Posts: 3
  • Karma: +0/-0
Re: Water Pressure - Few questions
« Reply #1 on: February 27, 2011, 10:22:37 PM »
Oh and to add - the house has a Belmac multifuel burner in the lounge, which I think has a wetback. I am not 100% sure if this is still operation. It may have been ripped out when the new cylinder went in.
Does this change anything when considering options for pressure increase?

I doubt we will even use the Belmac, as I have heard mixed results. The house has a heatpump and underfloor heating also.

Regards
J

Offline Plumber

  • Administrator
  • Hero Member
  • *****
  • Posts: 736
  • Karma: +52/-2
  • ***#1 Plumber***
Re: Water Pressure - Few questions
« Reply #2 on: February 28, 2011, 09:01:48 PM »
Hi Wana Go,

Sounds like you got yourself a very interesting home.

I agree with you consulting a plumber before taking any action as any advise given can be wrong without having seen the site first.

If a wetback is connected to the HWC directly (not via a heat exchanger),then you CANT install a valve this would be very dangerous and must remain open vented. Extending the pipe would increase the pressure in the system but it would also increase the pressure in the tank. In total it should not increase the recommended pressure rating provided by the manufacturer.

This would also apply if no wetback was connected and you installed a valve on the vent. The valve rating plus your total vent length would equal the total amount of pressure and your right, they could freeze. so not recommended.

keeping it simple is the best way to go. Get a mainspressure HWC with a wetback coil or buy propper low pressure mixers e.g felton mix.

I hope the underfloor is not connected to the HWC, lol  ;D

Plumber


Please note that the advice I am giving is only my opinion and not necessarily a fact.  Please refer to our terms and conditions.

Offline WanaGo

  • Newbie
  • *
  • Posts: 3
  • Karma: +0/-0
Re: Water Pressure - Few questions
« Reply #3 on: February 28, 2011, 09:58:48 PM »
Thanks for the reply.

I realise about not going over the pressure rated of the cylinder etc. I have tried to google to find information on the cylinder, but I havent found a pressure rating as of yet.

In our old house, we removed the header tank and installed one of those UFO looking valves, and extended the pipe on the roof - based on the pressure rating of the cylinder. It worked very well compared to what it was like before hand. This was a few years ago now.

If we ignore the wetback possibility, as it could very well already been removed, and the cylinder is rated higher than the current setup - if we dont extend the pipe and we cant put a pressure releif valve on the vent above roof level due to possible freezing, what are the other options?

To change out a low pressure system, like what we have, what would it cost (very very approximately) to install a high pressure water cylinder?
From memory, all the taps in the house are standard looking taps, no mixers exept in the shower - which we would have to replace, and would want to anyway.
Pipe work, in a 1978 house I assume would be capable of handling high pressure... or do they vary and are not age related at all?

This house has a gabled ceiling and concrete upper floor which was apparently not common for this age of house.

Purely getting info, I will not be doing any of these mods myself. I appreciate any information at all.

Regards
J

Offline Plumber

  • Administrator
  • Hero Member
  • *****
  • Posts: 736
  • Karma: +52/-2
  • ***#1 Plumber***
Re: Water Pressure - Few questions
« Reply #4 on: February 28, 2011, 10:25:40 PM »
Hi J,

Most low pressure HWC are rated to 800 KPA max. so using a 7.6 KPA would be ok. Maybe all you need to do is increase the pressure on the pressure reducing valve? Have you checked where the water level is at the moment? 1.5 meters does make a difference.

In regards to your plumbing, if the cold pressure is stronger then the hot water pressure then you have an unequal system. That way you know all your cold water pipe is already on mains pressure so usually taps other then shower mixers should be fine. Replacing the HWC could be anywhere between 2500 - 3500 depending on size and location. Most plumbers that replace Topless shower mixers simply cut a larger hole, install a different mixer and then install a larger cover-up plate, can be chrome or simply white. Very common..

plumber


Share via digg Share via facebook Share via linkedin Share via twitter

Similar Topics

  Subject / Started by Replies / Views Last post
xx
Questions on running a gas and water line to a new garage

Started by wazzab

7 Replies
7217 Views
Last post August 01, 2011, 03:33:42 PM
by Jaxcat
xx
General Instantaneous water heater installation questions

Started by Rodza1

13 Replies
9055 Views
Last post August 21, 2013, 08:18:14 PM
by NZMoose
xx
more water pressure

Started by bell

4 Replies
4404 Views
Last post June 15, 2012, 08:04:43 PM
by integrated
xx
Low hot water pressure

Started by namelsss

8 Replies
8927 Views
Last post March 12, 2011, 06:58:10 PM
by Thunderhead
 
Share this topic...
In a forum
(BBCode)
In a site/blog
(HTML)