Possible to replace Wilo warm water circulation pump?

[harry]

There's more of it. It's not all washed away by running the tap for a while.

[ARW]

OK and how does the chlorine encourage the bacterial growth?

[ppmoore]

Again, many thanks for the replies.

The hot water circuit/loop has a blocking return valve (if that's what it' s called) beside the tank. This stops the hot water from the hot tank circu lating in the circuit due to natural convection, which I'm sure would cost a lot more, even with the pipes being lagged. This ensures that the water c an only be circulated when the pump is switched on.

I'm coming around to the idea that installed a new pump costing upwards of £150 on Ebay is a frivolous idea, just to save a few tens of litres of wa ter per day. I could instead either:

- take out and bypass the pump and ensure that the return valve is set to o pen, in which natural convection should ensure that there is always warm wa ter available in the circuit - probably an expensive option

- take out and bypass the pump and ensure that the return valve is set to b locking, to stop the circulation by convection

- just leave the pump in place, in which case the blocked impeller will sto p the circulation by convection

Now just have to convince the better half...

P

[harry]

It's the lack of chlorine encourages bacterial growth. So the greater the volume of unchlorinated water the more bugs you get. When the pump is started after being off for a while, they are all pumped back into the tank/system. And mixed in so running the tap doesn't help. If you have a pump at all, the only way to get round all this is to have it running constantly. Very expensive energy wise.

[Terry Fields]

You need to decide whether you want to save water (your original post) or save energy (which is what you seem to be talking about), do both, or keep SWMBO happy.

Circulating hot water round a system just in case you want some hot water from a tap seems to be swapping less water usage for greater energy usage.You'll need to calculate the cost of the losses on each and decide which is the least; or if your only target is water saving, how much water will replacing the pump save in terms of cost - from which you can work out how long it would take to pay you back.

Frankly, adding a flow restrictor and taking 5 minute showers would save you far more energy and water than gained by replacing the pump, which if you didn't replace would save you even more.

Of course, if it's a matter of doing what SWMBO wants, then like the rest of us, you're stuffed. Good luck.

[Dave Liquorice]

Or ensure that the water in the tank is regulary heated to >60 C (?) and that this scalding water is circulated. ^0C is really rather too hot to have coming out of the taps so a thermostic mixer would need to be fitte on the tank out put to bring the temp down to safe levels.

Circulating hot water is going to cost money for the energy lost and the electricty used. The 10l per shower water "saved" will never cover those costs. What is that about 3 quid per hundred showers, or about 2 months with two showers per day.

[harry]

That's exactly what is done in hospitals. Cost an absolute fortune when the Leggionaires thing came out. Both in terms of altering pipework and running costs.

[ppmoore]

Terry,

I think you've nailed it right on the head.

Thanks again.

far more energy and water than