Shower Pump Advice

[ltarrant]

Hi,

I am looking for some advice on which type of pump I should fit to improve the flow to the showers in my house. I am in the position where I am planning to completely refit both bathrooms over the rest of this year so all options are on the table as I don't need to worry about using existing pipe work into rooms.

I currently have a gravity fed vented system. 50 gallon cold water tank in attic and a 450 x 900 hot water cylinder (so estimating 110-120ltr). The cold water tank in attic is only 15cm off the attic floor. Both the main bathroom and en suite are on the floor below meaning a drop of only 50cm to the shower head. The result is pretty poor water flow to both showers.

To complicate matters there is no room in the airing cupboard to site a pump at the base of the cylinder. So I will have to stick it in the attic. I am guessing this means a negative head pump? Or is it still positive as the end outlets will still have a positive head?

Another option I was looking at was to fit 2 x Aqualisa Digital showers with built in pump as I’m refitting bathrooms anyway. However, I understand I need to fit dedicated supplies to whichever type of pump I fit. I am assuming both digital showers would need there own supply. I don't like the idea of fitting Essex flanges so had planned to fit a Surrey flange to cylinder but that would only give me only 1 take off. I am assuming I can't T off to supply another pump or the pumps could be sucking against each other?

I think therefore my best option is probably one negative head pump in attic to supply both showers. Recommendation everywhere seems to be Stuart Turner. So I am thinking of going for the Universal TechFlo Qt 2.3bar as ideally want as quiet as possible.

I guess I'm just looking for someone to confirm my thinking is correct as the negative head pumps aren't cheap. Cheers in advance for any advice.

Luke

 

[Madrab]

Stuart Turner are, IMO, the best to install.

2 aqualisa's can use the same feeds, it all down to adequate flow and pressure to ensure there isn't a dip in supply to each one when the other is activated, your gravity scenario probably wouldn't be able to cope.

If you are only creating 'power showers' with a limited duty cycle, then the QT will suit.
You will have a period of neutral head as the pipe rises in line with the cold tank so a universal pump may be needed to avoid any start up issues, that being said though if you can get more than 1L/min flow at the shower head then a standard pump may be ok.

Avoiding air in the system is essential and a flange will be needed as you suggest, the feed pipe looped below the outlet level may be needed too.

 

[ltarrant]

Thanks for the advice. I think I play it safe and go for a negative head pump.

What is meant by limited duty? I have a wife who likes to spend15 mins in shower in morning. I normally follow at some point with a quick in and out. I have too young boys who mainly bath in evening at moment but I guess I need to plan for when they are bigger and shower as well.

I am assuming my tank and cylinder will be sufficient. There's normally a good amount of time for cylinder to reheat after my wife as she leaves for work much earlier than anyone else leaves the house. However, her long showers are part of the reason I was going to limit the pump to 2 bar to avoid to much water being used.

 

[Madrab]

A pump's duty cycle is usually determined by the materials it has been made from. Basically it means, to avoid certain pumps overheating, wearing prematurely, it should only be run for a certain amount of time until it is rested.

With the ST QT U2.3 bar, it has a duty cycle rating of 30mins with 30 mins rest whereas the monsoon has a continuous rating, that's due to impeller and casing being made of brass. If noise is the defining factor then the Monsoon U3bar is only 2db louder than the QT, nothing you would notice I wouldn't think. A little lower in max flow but @ 40L/min I'm sure it would be plenty.
Can cost more again of course but it depends on what you need.
Usage will depend on hot water recovery too, how quickly the hot water recovers after 1 shower etc.

There are a few things you need to consider & factor into the design. Ideally I would say that the stored Cold water should be at least 50Gal (230L) and the HW cylinder at least 150L (30Gal) or more, again dependent on overall requirement.

 

[slapper]

Hi,

I am looking for some advice on which type of pump I should fit to improve the flow to the showers in my house. I am in the position where I am planning to completely refit both bathrooms over the rest of this year so all options are on the table as I don't need to worry about using existing pipe work into rooms.

I currently have a gravity fed vented system. 50 gallon cold water tank in attic and a 450 x 900 hot water cylinder (so estimating 110-120ltr). The cold water tank in attic is only 15cm off the attic floor. Both the main bathroom and en suite are on the floor below meaning a drop of only 50cm to the shower head. The result is pretty poor water flow to both showers.

To complicate matters there is no room in the airing cupboard to site a pump at the base of the cylinder. So I will have to stick it in the attic. I am guessing this means a negative head pump? Or is it still positive as the end outlets will still have a positive head?

Another option I was looking at was to fit 2 x Aqualisa Digital showers with built in pump as I’m refitting bathrooms anyway. However, I understand I need to fit dedicated supplies to whichever type of pump I fit. I am assuming both digital showers would need there own supply. I don't like the idea of fitting Essex flanges so had planned to fit a Surrey flange to cylinder but that would only give me only 1 take off. I am assuming I can't T off to supply another pump or the pumps could be sucking against each other?

I think therefore my best option is probably one negative head pump in attic to supply both showers. Recommendation everywhere seems to be Stuart Turner. So I am thinking of going for the Universal TechFlo Qt 2.3bar as ideally want as quiet as possible.

I guess I'm just looking for someone to confirm my thinking is correct as the negative head pumps aren't cheap. Cheers in advance for any advice.

Luke

I personally wouldn't fit a Stuart Turner pump, because they have sub contractors who will come and inspect your work if you have a problem, if its your problem, you will be charged an exextoranatemount for your mistake. Try Salamander pumps, much better service

 

[Madrab]

Whilst I don't have a real issue with salamander pumps, the only thing I have seen with them is impeller breakup issues a couple of times, root cause was placed on the hot water being over 60deg.
That's why I would always recommend a fully brass design for continuous use pumps.
ST have a great rep and as long as they are installed correctly and maintained then support shouldn't be an issue. Longer guarantee on ST pumps too I believe.

That being said, I do believe that salamander have a new range of fully brass out now (old brass still had plastic impellers) but being brand new I don't think they have a noise rating yet and may be longterm untested.

 

[ltarrant]

Hi, thanks for comments. I am hoping to install everything correctly hence coming here for advice. So hopefully I won't need to worry about having done anything wrong should I get any issues. So I think I will stick with the Stuart Turner pump as this is what most seem to recommend.

I think I will go for the Monsoon 2 bar. Like the idea of the continuous rating and full brass.

Just been reading the install notes for this pump (http://www.stuart-turner.co.uk/media/4331-Monsoon-Universal-Twin-ShowerPump-WholeHousePump-IG.pdf) which has raised a few questions.

I can use a standard Surrey flange? I don't need to use an ST top entry flange? It won't affect the warranty?

According to the install document if I use a top entry flange I don't need to worry about an inverted loop on the HW cylinder outlet. Or is it best practice to do anyway?

Install docs suggests a min static inlet pressure of 0.5m from base of CW storage tank to pump. My storage tank in only raised up 15cm from floor of attic due to low roof. Is that not enough?

It says I should have a dedicated CW feed from the storage tank which is fine. However it also says it should be 25mm lower than the take off for the HW cylinder feed. However, the current HW cylinder feed is at the very base of storage tank so it's not possible.

I suppose I could redo pipe work connect pump to existing low outlet on CW tank and connect the existing cylinder feed to a new connector 25mm higher. I'm not should I understand why it's really necessary though. Surely if the CW tank runs low the feed to the HW storage will be cut off Sooners? I've also seen it suggested although not mentioned it ST install guidance that take offs should be on opposite sides of cylinder.

Cheers again for advice.

Luke

 

[Madrab]

I can use a standard Surrey flange? I don't need to use an ST top entry flange? It won't affect the warranty?

Call ST, You need them to confirm that, best getting the word from them as they cover the warranty.

According to the install document if I use a top entry flange I don't need to worry about an inverted loop on the HW cylinder outlet. Or is it best practice to do anyway?

If ST are happy not to include a loop using a top entry flange then not needed

Install docs suggests a min static inlet pressure of 0.5m from base of CW storage tank to pump. My storage tank is only raised up 15cm from floor of attic due to low roof. Is that not enough?

As long as you can provide the min flow to activate the reed switch (0.5L/Min) then that should be enough, again tho, give ST a call if there's any concern, I am sure they will clear it up, as there are other ways to activate the pump if it's not enough.

It says I should have a dedicated CW feed from the storage tank which is fine. However it also says it should be 25mm lower than the take off for the HW cylinder feed. However, the current HW cylinder feed is at the very base of storage tank so it's not possible.

Swap around if you can, you want the hot to be cleared first to avoid scalding risk, the pump will still draw some hot water even when the feed is exposed, so you want it to run dry first. Opposite side would be preferable if achievable.

 

[ltarrant]

Damn it. Spoken to Stuart Turner and all their pumps require a minimum of a 0.5m drop to pump to ensure sufficient supply.

I have no options to raise up CW storage tank as the pitch of the roof means the roof is low and there is no space to raise up tank higher.

I could fit a shelf in the airing cupboard but I had this in a previous property and there was a lot of vibration on shelf when the pump ran. You could hear it through the whole house and woke everyone with my wifes 6am showers. My preference was to put in attic on a stone slab with carpet to keep as quiet as possible.

I think I might just go back to square one. I was planning to fit an Aqualisa Visage Digital Shower (http://www.aqualisa.co.uk/our-products/our-shower-ranges/visage-digital/concealed-digital-shower-with-adjustable-head-and/?product=18183) in the main bathroom. These are available for about extra £100 with the pump built in. I was put of this a it would mean fitting another similar unit in the ensuite so 2 pumps rather than just one.

My only concern about doing this was getting 2 feeds from the hot water cylinder to 2 different processor/pump units. Can I just split the shower feed off the surrey flange? If both showers are on at once could this not potentially mean they are pulling water from the other pump?