hot/cold mixing problem

[mirz]

recently bought new place (about 7 years old).

problem what we are facing is very difficult to mix hot and cold water. water taps look in good condition. DUX water heating unit is in good nick too. set it on full hot.

main shower is about 3 m from hot water unit, and even if no one else is using water, it takes too long to set proper mixture of hot/cold water.

its not only on one tap, everywhere in whole house is same problem.

can someone pls give me any idea, what is causing this?

- low quality taps?
- problem with heating unit?
- or something else ?


thanks.

[Barry_White]

Hi Mirz

Sometimes with the washers in some taps is that they expand as the water gets hotter so restricting the flow of hot water which means you have to constantly keep adjusting the water until the washer fully expands and stops restricting the hot water flow.

Perhaps a change to taps with 1/4 turn ceramic washers would overcome the problem.

[joe greiner]

How long is too long? Before adjustment is possible, you need to flush the cold water from the hot water line; this should be a function of distance from the heater. Also, where are the hot water lines run? If they're not in a heated space, pipe insulation would help to maintain the temperature of the hot water between the heater and the tap.

Joe

[mirz]

thanks guys for your response.

For Bazza, i heared those ceramic washers are bit hard to use specialy on shower taps. but i think i would give them a try on bathroom sink first and see if they will make difference.

For Joe, Hot water starts quickly, but let me make it more clear, because i think in OP i made it very confusing.

- opened hot water tap, 5 seconds hot water is all there, but very hot.
- now just opened cold water tap, now its all very cold water.
- then keep opening hot water tap, and before its almost full now its nice warm water.
- but in a second or two, its very cold again.
- now reduce cold water tap, almost near to close, now its warm again.
- started shower, some times it becoming cold, hot, and we are keep fidling with taps to adjust it.

- almost same with wash-room sink taps.
- kitchen sink tap is a seperate issue, its fine with hot, but if you open cold water, its too noise, and start making heavy viberations.

there is no issue of run out of hot water, its always there.
all pipes are running through roof in thick black rubber kind of pipes. cold water pipes are in roof as well, but they are copper. pipes are not exposed to direct harsh weather (according to my personal observation).

[Barry_White]

For Bazza, i heared those ceramic washers are bit hard to use specialy on shower taps. but i think i would give them a try on bathroom sink first and see if they will make difference.



Mirz

They are no good on places with gravity feed hot water tanks or pressure pumps.

But if you are on mains pressure they are ideal.

My brother in Sydney was having trouble with his taps and he replaced them all with the ceramic washer taps and he reckons it was the best thing he ever did.

[journeyman Mick]

Are you on town water? Your problems sound consistent with a pressure pump system and different sized piping for hot/cold water. I suffered from similar until I replaced the pressure switch and bladder on my pump with a flow switch.

Mick

[mirz]

yes Mick i am on town water.

where could this pressure and flow switches be located in my house?

do i need a plumber to get them replaced or fixed?

[journeyman Mick]

If you're on town water then my above post is totally irelevant to your situation. The switches are fitted to pfressure pumps which feed tank water to a house.

Mick

[durwood]

I would think you have probably checked this :

Had this problem once, but it happened suddenly and nothing had been done to cause the problem. We are right at sea level and have fantactic water pressure.

The tap which isolated the hot water heater had been bumped and the flow of cold into the hot water heater was restricted. I turned it out again and no problem. Not enough hot water flowing out meant the cold was able dominate.

It would be good if this was the problem it was an easy fix, thought it was worth mentioning.

[mirz]

thanks durwood, will try this tonight.

[bricks]

Mirz- Possible causes could be.

If its an instantaneous heater, or solar gas boost heater. You may have fitted AAA rated water saving shower heads and taps- they don't work on those types of heaters.

As before you may have a blokage in the hot water line.

Seeing as your house is relatively new- your tempering valve might be busted and you need a new one.

If you have a pressure reducing valve in line to protect the heater from over pressure you may need one on the cold too.