power shower pump to second shower

hargo · 09-12-2013 09:36PM #1

I have a shower pump in the hot press which i have connected to ensuite shower, from memory i think it is a 2 bar pump. The shower in the bathroom is gravity fed about 1.2 metres and does not work well probably because the mixer needs a higher pressure than it is getting. It would be easy to connect bathroom to the shower pump also. Question is if second shower was used while the other was being used would it effect the first shower significantly. Both showers have thermostatic valves but would there be a danger of significant temperature change on initially turning on the second shower.
Also would there be a problem to the pump if only one side of it was used i.e. only hot water or only cold.
Thirdly is there any way to quieten these pumps as they make some racket.

Sparkpea · 09-12-2013 09:44PM

yes it would effect the pressure of both showers if both ran at the same time

what make/model is the pump?

if its advertised as a shower pump then thats pretty much what its guaranteed for, you would probably be best with a whole house pump.

corkgsxr · 09-12-2013 11:02PM

You could stick in one of the new monsoon 3 bar negative head.

New model is alot quieter.

The 3 bar would do 2 showers no problem.

About 700 euro though

hargo · 09-12-2013 11:20PM

Its a stuart turner st55 pump. Thanks

Sparkpea · 09-12-2013 11:36PM

I thought an st55 was only single propeller?

hargo · 10-12-2013 12:09AM

Sparkpea wrote: »

I thought an st55 was only single propeller?

Don't know about that or what difference it makes.
Some info on the plate;
RTG: STR (S2) 30 min @ 9L/min
Duty Head 12.5 metres @9 l/min
Duty Head 2 metres @ 35 l/min
Head Max 16.5 metres
Max working pressure 3.5 bar

K.Flyer · 10-12-2013 11:04AM

The ST 55 were a plastic bodied twin impeller pump. Really only designed for a single shower application, but are often found running a full bathroom and I have seen one running two bathrooms.
They are generally a noisey pump and it is not recommended trying to insulate them as they need plenty of air to stay cool.
The pump will struggle to run two showers at the same time. But you can connect the second shower / bathroom and see how it works out for you.
If it is very likely that two showers will be running at the same time, you are also going to have to consider how big your hot water cylinder is and how quick it can heat hot water for it all to be viable.

hargo · 10-12-2013 12:13PM

My tank is 200 litres which is why i didn't connect up the shower pump to the bathroom first time. But i do need to improve the output to the bathroom some way. It is not going happen all the time that the ensuite and bathroom will be going together but will occur at some time and i don't know if thermostatic valves will protect people getting two feeds from the one pump.
I think the mixer valve in the bathroom is restricting the flow of water a lot because if i got out the flow that comes from the sink mixer i would be happy enough.

corkgsxr · 10-12-2013 12:33PM

hargo wrote: »

My tank is 200 litres which is why i didn't connect up the shower pump to the bathroom first time. But i do need to improve the output to the bathroom some way. It is not going happen all the time that the ensuite and bathroom will be going together but will occur at some time and i don't know if thermostatic valves will protect people getting two feeds from the one pump.
I think the mixer valve in the bathroom is restricting the flow of water a lot because if i got out the flow that comes from the sink mixer i would be happy enough.

Thermostatic will protect. You shouldn't notice a change besides flow drops abit.

Iv a mira coda pro and there a brilliant bar valve. Great flow and not dear either.

Other option is fit a mira vigour. Which is basically a thermostatic pump on the wall. Costs about 240. Only needs 2 half inch pipes and a small power supply off a switched spur.

No need for 8 square.

Sparkpea · 10-12-2013 09:52PM

fitted a mira vigour last week and was impressed. for an on the wall pumped shower I normally use the aquastream but they are silly money these days, vigour well worth its price.

cerastes · 10-12-2013 10:04PM

Sparkpea wrote: »

fitted a mira vigour last week and was impressed. for an on the wall pumped shower I normally use the aquastream but they are silly money these days, vigour well worth its price.

Are they noisy? any quieter pumps, maybe something to just boost the pressure a bit, Id been thinking of what twin impellor pump to fit overall, for the piping to the bath and ensuite to raise pressure. Seems to keep coming up about the noise of them though, if there is hot water in the tank prefer to use it via the ensuite instead of the Triton thats in the bathroom, but we avoid using the triton late as it makes a bit of noise too.

Maybe for a pumped shower unit the wiring could be taken from the shower wiring if they only require a spur, as the shower wiring is 10sq

Sparkpea · 10-12-2013 10:21PM

no not overly noisy, but a pumps a pump and at end of day its gonna make some noise so need to allow for that and be flexible

cerastes · 10-12-2013 10:29PM

Sparkpea wrote: »

no not overly noisy, but a pumps a pump and at end of day its gonna make some noise so need to allow for that and be flexible

Thats the convenient thing about the ensuite shower, no noise at all.
The price of the wall mounted ones make it come close to maybe getting a pump in the ensuite.

shane0007 · 10-12-2013 11:31PM

Brass bodied pump are a lot quieter than their plastic bodied counter-parts, but pricier.

I came across a Lowara 3 bar booster pump that made me look twice to see if it was running. Very quiet with just a low hum. Compared to the Grundfos 4 bar, it was silent.

hargo · 10-12-2013 11:41PM

Is it ok if only the hot side of a pump is used. The way mine is connected to the ensuite the hot tap in the sink is on the same circuit. I have a pull down switch to give power to the pump when the shower is being used but sometimes forget to switch off the power and go to use the sink and the hot water brings on the pump. If that was used like that regularly would it effect the pump i.e. nothing on the cold side.

shane0007 · 10-12-2013 11:50PM

hargo wrote: »

Is it ok if only the hot side of a pump is used. The way mine is connected to the ensuite the hot tap in the sink is on the same circuit. I have a pull down switch to give power to the pump when the shower is being used but sometimes forget to switch off the power and go to use the sink and the hot water brings on the pump. If that was used like that regularly would it effect the pump i.e. nothing on the cold side.

Not good because the cold side is pumping against a closed circuit & will eventually damage the pump. They are twin impeller so only have a single shaft & both sides are pumping when pump is on.

corkgsxr · 11-12-2013 12:15AM

shane0007 wrote: »

Brass bodied pump are a lot quieter than their plastic bodied counter-parts, but pricier.

I came across a Lowara 3 bar booster pump that made me look twice to see if it was running. Very quiet with just a low hum. Compared to the Grundfos 4 bar, it was silent.

The new type monsoon are 1/4 the noise. I replace alot as we do alot of apartment work. And if a monsoon is fitted its replaced with a monsoon. But most are surprised how much quieter the new type is.

K.Flyer · 11-12-2013 03:02AM

shane0007 wrote: »

Not good because the cold side is pumping against a closed circuit & will eventually damage the pump. They are twin impeller so only have a single shaft & both sides are pumping when pump is on.

If it the tap was left running for a very long time yes, but the hot side pumps against a closed circuit as well when a cistern is filling, which its designed to do.

cerastes · 11-12-2013 06:31PM

K.Flyer wrote: »

If it the tap was left running for a very long time yes, but the hot side pumps against a closed circuit as well when a cistern is filling, which its designed to do.

is there not some kind of internal bypass before the output, in the case only one side is being used where there is a build up of backpressure on the other side to prevent damage?

rightjob! · 11-12-2013 07:07PM

if you are only looking at getting better pressure in your shower why not install a power shower? much better than installing a pump

K.Flyer · 11-12-2013 07:32PM

cerastes wrote: »

is there not some kind of internal bypass before the output, in the case only one side is being used where there is a build up of backpressure on the other side to prevent damage?

The Stuart Turners negative head model does have a bridge between the two outlets, but I dont think the Grundfos negative does, hence the two vessels and two pressure switches.
Otherwise No there is no built-in bypass.
But what exactly is the concern?
The positive head pumps are basically two individual pumps, one either end of a common motor, controlled by a common pcb and activated by individual sensors.
They both spin at the same time as each other and there is no crossover or by-pass, but the have been built like that for years.
Its only if it was left running for an excessively long time non-stop (hours?) that the water on the "closed" circuit side can reach boiling point and damage the seals and cause a leak.

cerastes · 11-12-2013 10:50PM

K.Flyer wrote: »

The Stuart Turners negative head model does have a bridge between the two outlets, but I dont think the Grundfos negative does, hence the two vessels and two pressure switches.
Otherwise No there is no built-in bypass.
But what exactly is the concern?
The positive head pumps are basically two individual pumps, one either end of a common motor, controlled by a common pcb and activated by individual sensors.
They both spin at the same time as each other and there is no crossover or by-pass, but the have been built like that for years.
Its only if it was left running for an excessively long time non-stop (hours?) that the water on the "closed" circuit side can reach boiling point and damage the seals and cause a leak.

Just looking at the pictures of negative head pumps, I have seen they seem to have a connection between both sides and the vessel, at I guess I could only think the expansion vessel is seperated in the middle by a bellows? but I dont know.
For positive head pumps, I just assumed a pump would be better off with a means to offload the built up pressure or else over time it would assist the deterioration of the pump, either a bypass back to the inlet side for hot and cold or some other means to stop the pump developing pressure that has no where to go. I didnt know that only short periods of running wouldnt have a detrimental effect.

I still think a bypass wouldn't be a bad idea, I know extra components means extra problems but it seems like something that could be added on at the design/assembly side without much difficulty.

just found this, http://www.showerdoc.com/grundfos-amazon-pump-negative-head-shower-spares

looks like the bar rating might just be base on the impellor?
A wall mounted pump probably work out cheaper when a thermostatic shower mixer is included.

hargo · 23-12-2013 12:24PM

Just an update to post. I connected the second shower to the stuart turner pump with gate valves before the mixer to reduce the pressure slightly if necessary as i was worried that hot water would disappear to quickly. So far it is a huge success. There is a negligible decrease in pressure when second shower is used at the same time. Also found out that the filters in the bar mixer were badly blocked causing my problem in the first place. Thanks for all the replies and merry Christmas to all our Boardies!!

power shower pump to second shower

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