Questions Re. Boosting Hot Tap Flow In Bungalow

[woodbine]

I have already posted a thread about boosting the flow/pressure to the hot kitchen tap in my bungalow.

http://www.ukplumbersforums.co.uk/p...-pumping-seperate-hot-supply-kitchen-tap.html

I have now decided to pump the hot supply to all my hot taps, via a single-impellor pump connected directly to the outlet of the vented cylinder.

Someone else on the forum has suggested the following Stuart Turner pump with an output of 1.5 - 2.0 bar.
[DLMURL="http://www.stuart-turner.co.uk/products/monsoon/standard-15-20-bar-max-single"]Stuart Turner - Standard 1.5-2.0 bar max Single[/DLMURL]

My question is, when they suggested this pump, I was only intending to boost the hot supply to the kitchen mixer. Now that I will be boosting all hot taps (kitchen, a bath tap and 2 basins), is the pump output OK for the 4 taps?

Just wanted to confirm, before I order one, as they also sell higher output single pumps.

Also, when I install the pump, are there any further measures that I should take to reduce pump noise (poss stand the pump on something)?

Thanks for any help

 

[Winston]

Polystarene base not on a joist

 

[david williams]

check manufactors spec on temp allowed for pump,and meathod of conection it is not recomended to come of vent pipework. also do you have any mixer taps in bungalow {other than kitchen sink taps}.if so just pumping the hot may cause you problems.to high temp to pump,and connections wich allow air bubbles to be drawn into pump will void your gaurentee

 

[Winston]

I have also wondered whether fitting a sheet of velco on top of the polystarene would help in reducing the noise as well.

 

[Alanka]

Yes, you should be careful that the temperature of the hot water entering the pump does not exceed the manufacturer's spec. Check it with a thermometer!

About a year ago I had a case where the plastic inlet elbow to a pump's hot water inlet had cracked and was leaking. I simply fitted a new elbow but the same thing happened again a few weeks later. On checking the inlet temperature I found that it was several degrees above the published pump spec! Evidently the plastics used could not stand these high temperatures.

In the end I fitted a thermostatic blending valve to the hot water inlet to the pump to limit the temperature, which has cured the problem.

 

[Bernie2]

Yes, you can also get cavitation with pumps if your not careful. Being honest its easier to Google it and get information about cavitation that way than it is for me to try and explain it.

Basically its stopping air being drawn into the suction side of the pump.

 

[MarkB]

Also, when I install the pump, are there any further measures that I should take to reduce pump noise (poss stand the pump on something)?

One of the Tech guys from Stuart Turner reccomended standing their pumps on a piece of concrete slab. I've fitted a number of pumps like this now and they do seem quieter as they transfer less vibration.

You can get 450x450 slabs for a couple of quid and cut them to size if need be.

Mark

 

[woodbine]

Thanks for the replies so far.

Bernie2 mentions cavitation. Is this likely to be as a result of pumping directly from the hot outlet from the top of the cylinder?

Also, will the 1.5 - 2.0 Bar pump be ok for my needs (ie. kitchen tap, bath tap and 2 basins - I live alone if that makes any difference)?

Ian

 

[Plumbstar Tom]

Yes cavitation will occur by takin the feed from the top of the cylinder as air is lighter than water it rises in the cylinder. Take the feed from an Essex flange preferably if no take it from below the vent T.

Cavitation will dry out the pump and can cause a bad leak

 

[Bob Croft]

Have a look at Salamder pumps technical information, I believe it is on the net. There is a lot of valuable information that will answer your questions.

 

[Bernie2]

Another point to consider, is that a pump can turn a shower into a power shower, which I think, are banned in parts of the US because they use too much water.

Our government is looking into water use and will probably amend the Building Regs on water use. Basically I suppose, if they get everybody on a meter then you can adjust use by unit price.

Seems pointless to me. We live on an island where it rains a lot, yet seem to run out of water. Why don't they build more reservoirs is the obvious answer, or is it easier and makes more money to charge people higher prices for their water.

Anyway I want new water, the stuff we use now people have wee'd in.

 

[Plouasne]

Another point to consider, is that a pump can turn a shower into a power shower, which I think, are banned in parts of the US because they use too much water.

Our government is looking into water use and will probably amend the Building Regs on water use. Basically I suppose, if they get everybody on a meter then you can adjust use by unit price.

Seems pointless to me. We live on an island where it rains a lot, yet seem to run out of water. Why don't they build more reservoirs is the obvious answer, or is it easier and makes more money to charge people higher prices for their water.

Anyway I want new water, the stuff we use now people have wee'd in.

Your last paragraph Bernie, fishes have as well, and also kraped in it

 

[dontknowitall]

Woodbine - not sure if this will help but ...

Just returned from a house where hot water flow is poor. They have a fairly large combi boiler but since installation (by other plumbers) the bath has taken ages to fill although central heating is fine.

Looking in the boiler the plate heat exchanger has corroded and water is leaking everywhere.

Before automatically fitting a new one, I felt some testing was required:

Mains water pressure is 3.8 bar. Water flow rate around 18 litres per minute. So far so good.

Hot water flow rate is 6 litres per minute (everywhere, not just bath).

Contacted manufacturers who confirmed my suspicions. They need a pressure reducing valve to reduce water pressure to 2 bar before it enters the boiler. Then when done, I can change old heat exchanger and service the boiler. The manufacturers tell me this should sort out the hot water flow as the boiler can cope with 2 bar but not with 3.8 bar and, presumably, will create the hot water flow as required.

I've mentioned this as the manufacturer has now confirmed what I was feeling all along. It could be that if you have a combi boiler, the pump you're thinking of installing might not do anything to solve your problem.

As I said earlier, hope this helps.

 

[woodbine]

Thanks Dontknowitall, but its a vented system, so no problems like you describe. However, I have a few more questions;

So it looks like I need to fit a surrey flange to avoid dragging air into the pump. Normally, the S flange has 2 outlets, one to shower, one to taps/vent. As I am pumping to all hot taps (N.B. no shower in my bungalow), do i need to block off the exsting outlet pipe that goes to the hot taps from cylinder and just use the outlet on the S flange that would normally go to a shower?

The Stuart Turner pump has an output of 1.5 - 2.0 Bar. Someone has also suggested a Grundfos upa 15-90 pump, with an output of 0.5 - 0.75 bar. Which is the right output for my needs?