Shower water pressure

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rumpty

66 posts

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#151545 28-Aug-2014 18:03

There are a few threads here that relate to this topic, but none seem to exactly answer a problem I have with the shower in my house, so here goes.

The setup is a low pressure system, 1960s house, just an open HW cylinder vent pipe. The shower is basic by today's standards I suppose, separate hot and cold taps, full mains pressure on the cold tap.

The hot water flow in the shower is bearable when the hot tap is first turned on, but over the next 10 seconds or so, it reduces to something fairly pitiful. Barely enough for a decent shower, especially at this time of the year with the cold water temperature being low.

I think this HW flow has got worse over the last year or two. It seems to me that the Nefa valve can't maintain a decent head once the shower hot tap is turned on. The hot water flow is still reasonable in the kitchen, laundry etc. though.

So, can Nefa valves go bad in this way, and can they be maintained? The original valve was replaced about 1980 because it wouldn't shut off properly.

Thanks for any advice.

timmmay

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#1117476 28-Aug-2014 19:13

I solved the problem by putting in a new mains pretty hot water cylinder and completely replacing the bathroom. Works great now, bathroom is better than any hotel I've ever stayed in and I've stayed some nice places. I couldn't be bothered messing with a really old system. I put the cylinder in the ceiling cavity, reclaimed space in the house.

Sorry, not really helpful.

DarthKermit

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#1117511 28-Aug-2014 20:18

If you can't afford a whole new system, perhaps look at upgrading your shower mixer to a new one?

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gundar

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#1117531 28-Aug-2014 20:51

Hi

Not the anecdote you want, possibly, but...

I have a 1960's house and it's on a hill. When I moved in, I recall similar problems to yours. It took a lot of screwing around and money/time to reach the conclusion that since the cold water pressure was great, the only logical solution was an infinite gas water heated system. Possibly this is not available to you, but it came in at more than replacing the cylinder where a new cylinder did not guarantee good pressure. I also changed the shower head to one that is recommended for poor flow to get nice coverage as I like long hot showers with some consideration towards cost of heating the water.

All up, I recall it was about $3k (the gas mains was on the opposite side of the house) and the best money I've spent. The power bill noticably declined, almost immediately, too.

Good luck.

coffeebaron

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#1117540 28-Aug-2014 21:06

Add a boost pump :) one shower and all the hot water will be gone though :)

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Bung

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#1117602 28-Aug-2014 22:52

rumpty:

The hot water flow in the shower is bearable when the hot tap is first turned on, but over the next 10 seconds or so, it reduces to something fairly pitiful. Barely enough for a decent shower, especially at this time of the year with the cold water temperature being low.

I think this HW flow has got worse over the last year or two. It seems to me that the Nefa valve can't maintain a decent head once the shower hot tap is turned on. The hot water flow is still reasonable in the kitchen, laundry etc. though.

If you open the shower hot tap without the cold do you get he sort of flow that you get on the other taps?

rumpty

66 posts

Master Geek

#1117739 29-Aug-2014 09:23

...If you open the shower hot tap without the cold do you get he sort of flow that you get on the other taps?

No, the shower hot tap on its own has much poorer flow than any other hot tap, especially after 10 seconds or more of running, even with the tap turned on by many turns. It's a bit hard to assess exactly - the other taps don't have a shower head, obviously. That test is with no other taps in the house, hot or cold, turned on.

The shower outlet is of course higher than the other taps, but the shower hot water flow used to be much better. The clincher is that a bunch of teenagers used to use this shower, and there were no complaints! Solid evidence that things have changed for the worse now. Hence my suspicion of the Nefa valve. Does the performance of these valves deteriorate?

wellygary

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#1117741 29-Aug-2014 09:26

While the ideal situation would be either a mains pressure HW replacement or instant hot water, your problem is probably not related to the NEFA valve on the cylinder as otherwise you would be getting poor pressure from any/all hotwater taps,

It more likely that the tap/valve on the hot water tap of the shower is not fully opening, ( is there a mixer valve at all, or is it just Hot and cold plumbed together after the taps to the outlet?)

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rumpty

66 posts

Master Geek

#1117884 29-Aug-2014 12:24

wellygary: While the ideal situation would be either a mains pressure HW replacement or instant hot water, your problem is probably not related to the NEFA valve on the cylinder as otherwise you would be getting poor pressure from any/all hotwater taps,

It more likely that the tap/valve on the hot water tap of the shower is not fully opening, ( is there a mixer valve at all, or is it just Hot and cold plumbed together after the taps to the outlet?)

It's just hot and cold taps plumbed together after the taps. I'll check/change the washer in the hot tap.

mclean

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#1117899 29-Aug-2014 12:39

rumpty: It's just hot and cold taps plumbed together after the taps. I'll check/change the washer in the hot tap.

It could be the washer is no good. Sometimes they can swell when they get hot, which reduces the flow. Try a new neoprene one.

DarthKermit

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#1117995 29-Aug-2014 14:47

There could be a build up of mineral deposits in the pipe/valve to your HW mixer (thus restricting the flow). If the house is 1960's, this is quite likely.

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Dratsab

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#1118015 29-Aug-2014 15:48

DarthKermit: There could be a build up of mineral deposits in the pipe/valve to your HW mixer (thus restricting the flow). If the house is 1960's, this is quite likely.

I was going to suggest something similar to this.

My house is *extremely* old but it has been replumbed at some stage. Not sure how old the cylinder is but we have two large copper header tanks in a cupboard on the second level. Hot water flow to the kitchen and bathroom (bath and shower) was crap then a few weeks after we brought the place I noticed a whole lot of black bits and pieces coming out of the bath tap. I decided to leave it running for some time and after about 15 minutes a whole heap of this stuff (looked like paper wasps and bits of nesting) had washed out and the bath pressure has been good ever since. I then took the shower pipe off at the wall so it was just an exposed pipe sticking out, got a bucket and opened up the showers hot water tap. Same thing, except it only took a couple of minutes to clear - pressure's good now. Haven't got round to the kitchen yet but I'm expecting the same thing.

So...before anything else - make sure the pipes are clear.