Any plumbers out there?

[RogerS]

We are renovating our house. New showers/baths etc.

The cold water comes from our treatment plant down in the cellar. Pumped at around 2 Bar...I can alter that. The cold feed feeds the cold water tank in the loft and the cold taps. The cold water tank feeds the hot water tank which then feeds the taps etc in the house. Clearly an imbalance in pressure.

So I bought a whole house Stuart Turner pump (4.5 bar) as it was on offer but now am beginning to think that that was overkill and that all I really need is a pumped feed from the hot water tank at around the same pressure as the pump in the cellar?

Does that make any sense ?

TIA

 

[stevep]

If you are happy with the hot water flow and pressure, can't you just fit pressure reducing valves before the cold taps to balance this out ? Your risk is emptying the hot water cylinder quicker than you can fill it.

 

[morturn]

I am assuming you have a hot water cylinder?

If so, take a 22mm cold feed from the cold-water tank to the cold feed on the shower mixer.

Then fit a Surrey Flange to the cylinder and take a 22mm feed to the hot feed on the shower mixer too.

I should add; try to keep the bends smooth as possible and avoid elbows as connectors. I used to use a pipe bender and only straight connectors.

 

[Phil Pascoe]

If you are happy with the hot water flow and pressure, can't you just fit pressure reducing valves before the cold taps to balance this out ? Your risk is emptying the hot water cylinder quicker than you can fill it.

How does that work then? Every hot water tank I've ever seen or worked on has the hot pushed out by the cold - no cold, no hot.

 

[stevep]

I was having a blonde moment.....forgot the hot comes from the top !

 

[RogerS]

Thanks for the suggestions guys but modern taps (at least the ones that SWMBO chooses !) need a decent pressure to work. You don't get that from a gravity fed system. Also having a shower under a dribbling pitifully poor rate of flow shower is not something I relish.

 

[morturn]

There a first, I have a gravity fed shower with modern taps that defies gravity. It was particularly defiant this morning when I used it.

 

[RogerS]

There a first, I have a gravity fed shower with modern taps that defies gravity. It was particularly defiant this morning when I used it.

???

 

[sunnybob]

What is the exact problem? do you want more pressure in the shower?

If you only have one shower then a shower pump that boosts hot and cold pressure is the way to go.
You dont need hot water under pressure any where else. In fact high pressure hot water can be very dangerous and needs safety valves.
If any particular tap is flowing very slowly, then investigate that pipe run for dodgy valves or crimped pipes.

 

[RogerS]

What is the exact problem? do you want more pressure in the shower?

If you only have one shower then a shower pump that boosts hot and cold pressure is the way to go.
You dont need hot water under pressure any where else. In fact high pressure hot water can be very dangerous and needs safety valves.
If any particular tap is flowing very slowly, then investigate that pipe run for dodgy valves or crimped pipes.

The cold feed is already pressurised by virtue of the pump in the cellar. The hot feed is not but gravity fed. We have three showers and a bath....hence why I went for the whole house pump.

But as has already been mentioned, there is the question of flow capacity to consider. Also I'm not up-to-speed on what determines the actual flow rate. I'm guessing that it is limited by the pipework and, say, the shower head. So if you have a house with three showers, say, then does 4.5 bar get divided by three so each shower gets 1.5 bar? Then there is the flow rate to consider, as I already mentioned.

Maybe all I really need to do is get a booster pump in the hot feed.

 

[Phil Pascoe]

Make sure if you have any isolating valves that they are full bore - they are not usually fitted as they are more expensive.

 

[RogerS]

Thought I'd share this with you.

Dear Sir, Re: Whole of House Pump - Some advice which may assist in your choice of power wink

I took the wrong advice from 'the plumber from hell' about 5 years ago.. he told me I NEEDED a 5.5bar whole of house pump as our corner bath/Jacuzzi stated it required 3 bar and above.. yes that's right.. needed !

On first trying the shower with its inbuilt body massage nozzles (trade descriptions suit duly filed for change of name to jet blasting cabinet), the mighty power of the jet wash was truly experienced.. with ones private parts being blasted against door and desperately leaning forward into the storm muttering, "Must switch off before I drown.." the force was no different to that of my Karcher, albeit somewhat hotter.. Actually, a Steam Cleaner would be a better description. As the valve closed, the whole shower cubicle rocked as the pipes flexed due to the pressure, and I watched the torrent in the base slowly start to drain.. my ankles were still in about 3" of water eek "I'm still alive", I muttered whilst grabbing large breaths of air. I opened the blast doors shower doors and stepped out of the Abyss.

I staggered out of the spare rooms on-suite and into our bathroom to dry my face, arms outstretched in a poise not dissimilar to that of a zombie. With out thinking and hovering over the waterfall glass sink, I grabbed a face flannel and pulled on the lever to once again summon the God of water. Clearly the brain was suffering from shock because even a madman would not once again unleash the torrent. This time in a clam shaped and very open glass sink.. but I'd already pulled the tap and at that exact moment had envisaged the drama about to ensue. In slow motion, I felt the vibration coming up through the floor as the angry water came screaming out of the tap and watched as the inevitable tidal wave formed in the blink of an eye. Waterfall?? laugh "Noooooooooo!", I stammered, and held up my face flannel like a crucifix against the devil, but the devil was laughing too hard and I knew I was doomed. Obviously closing the valve would have been the sensible thing to do, but instead I stepped away in fear to witness the spectacular water feature that I had now installed in my bathroom. The fan shaped waterfall took no prisoners - water was directed directly squarely at the ceiling as its first port of call, narrowly missing the light fitting. I was like Homer watching a butterfly, I observed, again in slow mo, as everything in the room was consumed in water. After realising that it would not stop until I closed the tap, I reached out and struck the top quelling the flow in a manly fashion. The water stopped but I could hear the pump still running..

Now worrying that the pump from hell had possessed the rest of the house, I ran downstairs to see if water was leaking from anywhere else. My wife was walking towards the kitchen sink and she said," Oh that's strange.. there is water dribbling out of the tap... may be it's not shut fully". I watched her hand reach out to check the valve and let out another, "Nooooooooooooooo!!!" but it fell on deaf ears and she pushed first, then while looking at me like I was deranged, pulled on the lever from Hell and I watched as the swan neck raised from the pressure before delivering its payload like some heat ray from a martians' tripod.. she did the same as me and stepped back. The force was incredible, we now had an upward fountain which was ricocheting off the ceiling. Doing the man thing I ran in fearless and closed the valve. The pump was still running in the back ground.. "Don't move" I stated and went to the pump and pulled the fuse. "It's safe now" I said

I think I will be selling the brand new Monsoon 4.5 bar whole house pump.

 

[Phil Pascoe]

My b.i.l. fitted out a bathroom in a London flat belonging to a daughter of an immensely wealthy man. The centre rose alone had a 3,500 litre header tank. There was a leak one weekend while they were working there (fortunately it came from a flat above) and as the flats were unoccupied it was not found until the Monday morning - the total insurance claims were £4.5million. I expect their systems were pumped.

 

[sunnybob]

from your fist statement, the hot tank is gravity fed from the cold tank.
you cant pressurise the whole system if one half of it is gravity fed from the other.

Youre talking about a complete replumb. lose the cold tank, fit a pressurised hot water tank. Not a cheap option, but I dont see any other way of running those showers with a good pressure.

A system boiler or large condensing boiler MAY work, but that would need an on site evaluation.

Just so you know, my entire house is pressurised by a pump. The 1000 litre cold storage tank is BEFORE the pump. there is a pressurised hot tank on the roof along with a couple solar panels. I have the pump regulator set at 3.8 bar, with a 6 bar pressure relief valve, and two people can use showers at the same time, but three?, nah.

 

[RogerS]

from your fist statement, the hot tank is gravity fed from the cold tank.
you cant pressurise the whole system if one half of it is gravity fed from the other.

......

I know. But if I have a pump on the output of the hot water tank then the hot feed becomes pressurised.

 

[Distinterior]

In an ideal world, you would need to have the Hot & Cold water supplies to your showers at the same pressure ie. Balanced supplies.
If you wish to fit a pump on the Hot water side, make sure it is capable of maintaining the same pressure and flow rate to match your Cold water pump in the basement..."around 2 Bar"

If there is too much of a difference in pressure & flow rate between the 2 supplies, the shower valves will not work as they should.

If you decide to go this route, buy the best quality Hot water pump you can. Cheap pumps do not last long and when they fail, they can spew water all over the place.....!!!! and at 2 bar pressure, thats a lot of water!

 

[jimmy_s]

Your borehole pump serves the cold water header tank and also cold water outlets. Your HW cylinder is open vented/ gravity fed.

You could just pump the hot water by fitting a suitable pump to the hot water cylinder. The things you need to watch out for are pressure imbalances and the cold water supply being maintained.

With regards to pressure imbalance - you would probably want to fit pressure reducing valves after both the borehole pump expansion vessel and the shower pump expansion vessel (use a negitive head type). you would ideally set the pressure reducing valves to the same pressure so your hot and cold water supplies are balanced. You might want to fit a larger expansion vessel to the shower pump to help even out pressure fluctuations.

You may have an issue with the cold water supply - normally the flowrate from a borehole pump is quite low as they are generally sized to feed a header tank. The low flowrate keeps the cost of filters down as well. If you run all the cold water supplies off the borehole pump you may find that at times your borehole pump can't keep up with demand and the pressure drops. You can resolve this by fiitting a large expansion vessel after the borehole pump system but before the house.

So you could do it with a boosted hot water supply but it may be a bit of a faff. Peronally I would boost the whole house and fit an unvented cylinder.

 

[pcb1962]

If you decide to go this route, buy the best quality Hot water pump you can. Cheap pumps do not last long and when they fail, they can spew water all over the place.....!!!! and at 2 bar pressure, thats a lot of water!

Stuart Turner Monsoon are the ones to go for.
I've had a 3 bar twin in daily use for over 10 years without a hiccup.

 

[RogerS]

Thanks all.

Jimmy_s ....I should have explained the water treatment plant in more detail. The borehole pump feeds rather a lot of tanks and so sufficient water is not an issue ! The photo doesn't make it clear but there are the equivalent drop tanks to the left of frame as there are on the right.



and this is the cold water pump with pressure vessel



Presumably if I just cap of the expansion pipe from the hot water cylinder it becomes non-vented?

I did read someone suggesting putting the pump between the cold water tank and the feed to the hot water tank (unvented)

 

[sunnybob]

whoa mule. thats a no.

Now we have the situation described above where the hot pump scavenges the hot tank faster than the cold pump can fill it.

That way lies disaster Luke.