Grundfos Home Boster Pump

M

morrismini

http://www.grundfos.com/web/homeuk.nsf/Webopslag/DMAR-5UTLDA
pdf instructions and specifications on site.
http://www.grundfos.com/web/homeuk....fa180256e0f00563537/$FILE/UPA 15-90 05 03.pdf

This pump is around £112 to buy.
http://www.plumbnation.co.uk/site/grundfos-upa-15-90-home-booster-pump/

I was thinking of using it on a DHW secondary circulation loop. The idea was that flow would be detected when a tap is open. The pump switches on, via the internal flow switch, and takes water from a cylinder around the loop back to the cylinder. This would reduce the dead-leg time considerably and it only turns when a tap is turned on. Hot water would fill the loop pipe quickly. It switches when the flow is 2 litres per minute. small tap turn ons will not turn it on.

The pump can be switched like a normal pump if need be with the flow switch by-passed.

Has anyone any experience of this pump. It is cheaper than the Comfort range. The comfort range has integral stat, check valve and timer, so is more expensive. This Home booster seem to fit the bill just using the internal flow switch. If no tap is on no hot water runs around the loop. When the tap is on water is pumped to the tap very quickly.
 
Sponsored Links
Joined
28 Oct 2005
Messages
13,597
Reaction score
3,221
Location
Daventry
Country
United Kingdom
An interesting theory but I think you'll find it won't work as you expect it to. If it only operates once the tap is switched on, you will still have to draw off the same quantity of cold water before you get hot to the tap, as the amount of cold water in the pipe between the cylinder and your tap will not change. It would reduce the time required for the hot water to reach the tap by increasing the flow rate, but it would do this whether you installed the secondary loop or not, making the loop redundant. In fact the loop may hinder you as some water would be forced back to the cylinder rather than out of your tap, and you would also end up with a loop of warm water that then goes cold, thereby wasting energy heating water you're not going to use.


So, in short, it depends what you're trying to achieve. If you're trying to save water you need a properly-installed secondary loop with a bronze pump. This would either run constantly or you could feasibly have it running off a timed switch that you operate by the desired outlets before you open the tap, although to my mind that's a bit of a faff.

If you're just trying to increase flow to the taps then the whole house pump would be a good option but it's not going to save you any water and the secondary return is pointless.

Hope this helps
 
M

morrismini

An interesting theory but I think you'll find it won't work as you expect it to. If it only operates once the tap is switched on, you will still have to draw off the same quantity of cold water before you get hot to the tap, as the amount of cold water in the pipe between the cylinder and your tap will not change. It would reduce the time required for the hot water to reach the tap by increasing the flow rate, but it would do this whether you installed the secondary loop or not, making the loop redundant. In fact the loop may hinder you as some water would be forced back to the cylinder rather than out of your tap, and you would also end up with a loop of warm water that then goes cold, thereby wasting energy heating water you're not going to use.


So, in short, it depends what you're trying to achieve. If you're trying to save water you need a properly-installed secondary loop with a bronze pump. This would either run constantly or you could feasibly have it running off a timed switch that you operate by the desired outlets before you open the tap, although to my mind that's a bit of a faff.

If you're just trying to increase flow to the taps then the whole house pump would be a good option but it's not going to save you any water and the secondary return is pointless.

Hope this helps

Thank for the input Muggles. What I am trying to achieve is to reduce the time for hot water to get to the taps. You state, "you will still have to draw off the same quantity of cold water before you get hot to the tap," This I disagree with. If a tap 20 foot away is opened then the pump kicks in and it can shift 23 litres of hot water a minute around the loop. This is around 0.4 litres a second. It will be a mater of seconds before hot water is at the taps, and a saving of water and the pump only run when needed, so saving electricity. Simple installation as well. This means a permanently hot/warm loop is not required. OK there will be more of lag than having a permanently hot loop, but not that much to worry about.

The loop is used as a means to get hot water to the taps fast. Hot water runs past the tap on the loop and gets to the point of the tap quickly. If there was no loop there would be little gain in installing the pump apart from boost the pressure at the taps. If there is an increase in pressure at the taps because of the pump then fine. That is not the prime aim of using this pump. There is no need for pipe stats or timers. A flow regulator can be fitted where the loop enters the cylinder to maximise the time taken to get hot water to the taps and reduce excessive over-cooling of the cylinder. The loop of course would need to be well insulated. That in itself would make matters better as residential heat is retained giving hot water faster to the taps.

These pumps are quite cheap, about £80-90 cheaper than Comfort or normal bronze pumps and are not brass bodies being cataphores coated. Why aren't the rest of them made this way to get the prices down? The flowswitch can be switched out and run as per a normal switched pump. That means it can be fitted as a normal secondary circulation pump switched by a pipe stat.
 
Joined
18 May 2004
Messages
23,715
Reaction score
960
Location
depends where i get sent
Country
United Kingdom
it can shift 23 litres of hot water a minute around the loop. This is around 0.4 litres a second. It will be a mater of seconds before hot water is at the taps,

and all over everythig else at that flowrate :idea:
 
Sponsored Links
M

morrismini

What does not go out of the tap will continue around the loop taking hot water to the tap point very quick. You do not have to open the tap fully. ;)
 
Joined
18 May 2004
Messages
23,715
Reaction score
960
Location
depends where i get sent
Country
United Kingdom
so your going to have a secondary loop with a pump that only switches on when you open a tap

why

what you save in electricity you use in gas warming the water in the loop then leave it to cool

seems a bit of a waste to me
 
M

morrismini

so your going to have a secondary loop with a pump that only switches on when you open a tap

why

what you save in electricity you use in gas warming the water in the loop then leave it to cool

seems a bit of a waste to me

A full explanation was given above.
;)
 
Joined
17 May 2008
Messages
8,416
Reaction score
1,129
Country
United Kingdom
Why use a pump (and waste energy) to deliver what mains pressure will deliver anyway?
 
M

morrismini

Why use a pump (and waste energy) to deliver what mains pressure will deliver anyway?

That is the point. The flow/pressure alone from the cylinder will not deliver without a loop. You need a loop and a pump taking DHW from the cylinder to the tap ASAP. That means DHW runs right past the tee of the tap and back to the cylinder.

This only running when needed is used on ships to conserve water. Infra-red detectors are used in toilets to only flush urinals when people are in the toilet. The same idea could be used in a remote bathroom with long DHW dead-legs. Someone enters and movement around the basin brings in the secondary circulation pump, when they leave, or they are in the shower and it is off. It would only pump when you need "instant" hot water at the basin. A wait at the shower is not a problem and that would be reduced as most people would have to walk past the basin anyhow, activating the pump.
 
Joined
17 May 2008
Messages
8,416
Reaction score
1,129
Country
United Kingdom
Sorry Dr DrivelakaBigburnerakaWatersystemsakaGeorgeBramwellakamorrismini but this idea is unnecessary. :rolleyes: ;)
If it was a large property with multiple branches off the loop then hot water as muggles has stated would never reach the taps.
Stick to the office job.
 
M

morrismini

Sorry Dr DrivelakaBigburnerakaWatersystemsakaGeorgeBramwellakamorrismini but this idea is unnecessary. :rolleyes: ;)

Have you been drinking? My original question was, "Has anyone any experience of this pump?" I know what I am doing will work. I want feedback on the reliability of the pump. If people want to comment on what I am doing, and add some value, that is great. So far no one has added any value, as no one understood what I was proposing which is not difficult. I thought the professionals would understand it, maybe they are resting on a Sunday.
 
Joined
8 Jan 2005
Messages
19,003
Reaction score
1,568
Location
Bath
Country
United Kingdom
I think it would work as well if you fit a check valve near the cylinder return, and solve air being suck in. :rolleyes:

Grunfoss are one of the better brands.
 
Joined
17 May 2008
Messages
8,416
Reaction score
1,129
Country
United Kingdom
I can see your logic but still don't think it would work on a large loop.
And NO, I have no experience of this pump.
 
M

morrismini

I think it would work as well if you fit a check valve near the cylinder return, and solve air being suck in. :rolleyes:

Grunfoss are one of the better brands.

Ah! Some feedback on the pump. thanks. In a forum like this if the pump is a naff model many would probably know, so worth asking the question. OK a check valve near the cylinder. That would stop gravity circulation out of the loop. An anti-gravity loop in the pipe will stop that.

I can't see how the check valve would stop air being sucked in. The idea is to put the pump on the draw-off pipe before the taps. Air being sucked in via the open vent pipe is a problem that can be overcome by using a Surrey flange on the draw-off at the top of the cylinder. The pump only sucks from the cylinder water.
 
M

morrismini

I can see your logic but still don't think it would work on a large loop.

And NO, I have no experience of this pump.

I t is simple it pumps DHW very fast to the tee off point of the taps. This naturally would reduce waiting time for DHW to come out of the tap. It will not eliminate the initial cold water at the tap, as a secondary circulation loop would. It will vastly reduce the waiting time. that is pretty obvious. There are knock-on benefits of less electricity used as the pump does not run continuously, less water wasted, less energy wasted in the loop and some increased pressure at the taps which is a welcome side benefit and not what the prime aim is.

OK you know nothing of the pump.
 

DIYnot Local

Staff member

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.


Are you a trade or supplier? You can create your listing free at DIYnot Local

 
Sponsored Links
Top