Annoying shower pump job.

[europhil]

Please be gentle, I'm new to this forum. and thanks in advance for any advice.
I've had a customer ask me to replace a shower pump, The one they have is an Aquilisa 1.5 bar twin impellor.
So i priced it up, Then went round to fit the replacement.
He wasn't happy as the pressure hadn't increased. The thing is, He didn't ask for a bigger pump, Just a replacement.
I've checked his old pump, and apart from a bit of a cleanup, It's in pretty good shape.
So to keep him happy i've had an idea.
I use both the old pump and the new one by teeing the cold feed to both inlets of one pump, and the teeing the hot feed into both inlets of the other pump. Therefore i'm using both impellors of both pumps for each feed.
What do you think? Will it increase the flow? Or will i be wasting my time?

 

[Howsie]

I will probably increase flow but may result in unpredictable results. Personally I think this sits with the customer, but it's your call if you think you may have more work coming from them down the line. You could always sell both of them of fleabay and put the money toward a new pump. ST would be my choice.

 

[europhil]

It looks like you have read the situation. I'm trying to keep him sweat.

 

[Ray Stafford]

I think you would also be invalidating the warranty on your new pump.

Although there are plenty of 2 and 3 bar pumps around, for an ordinary single outlet shower, 1.5 bar is usually pretty good. Is there something else in the system limiting the pressure or flow? From your experience, was it delivering 1.5 bar of pressure at the shower? Did the customer say anything like - "it was fine when it was new, but..."

 

[europhil]

He did say "it was fine when it was new". However, I'm starting to get a bit suspisious. He has just told me that it's his 3rd pump. I don't believe him. This model hasn't been made for a long time.
Also, i'm not putting them in series, my plan is to run both in parallel, One doing the hot and one doing the cold.
I did think about running them in series, but i don't think it'll work. It would be like putting the mains straight into the second pump.

 

[Ray Stafford]

He did say "it was fine when it was new". However, I'm starting to get a bit suspisious. He has just told me that it's his 3rd pump. I don't believe him. This model hasn't been made for a long time.
Also, i'm not putting them in series, my plan is to run both in parallel, One doing the hot and one doing the cold.
I did think about running them in series, but i don't think it'll work. It would be like putting the mains straight into the second pump.

Hi Europhil.

Yes, sorry I should have read your post properly - I have just edited mine to remove the bit about that.
.

 

[europhil]

to be honest i'm not sure if there is anything restricting the flow.
We don't get a great deal of power shower work up this way, so i can't really say "that looks about right, or that pretty slow".
But to give you an idea, The flow is decent, but no more than what you'd expect out of a decent combi.
No real wow that'll take your skin off.
If i could get 50% more out of it, then he'll probably be happy and i'll get some decent work from it. and if he isn't then my sus****ions are correct about him.

 

[Howsie]

1.5bar will not blow you away you're probably spot on with the combi comparison.

 

[Destroyer2813]

Really silly question which I'm sure you've checked but the shower heads clean right ?

 

[JCplumb]

If you have suspicions that he's a rogue customer then get paid however possible and don't do any more work for him.
If that means tee-ing each supply into a seperate pump then go for it.
Once paid, change his name in your phone to 'do not answer'

 

[europhil]

If you have suspicions that he's a rogue customer then get paid however possible and don't do any more work for him.
If that means tee-ing each supply into a seperate pump then go for it.
Once paid, change his name in your phone to 'do not answer'

That's the plan. Just get paid (i've shelled out enough). But i could be totally wrong about him.

 

[steadyon]

I'd be a bit cautious running the pumps in parallel, one for hot and one for cold unless the shower is a thermostatic one. Otherwise, if the cold failed for some reason, you'd be pumping hot only to the shower, with a risk of scalding. With a single pump if the flow fails the pump shuts down both cold and hot.

 

[JCplumb]

I'd be a bit cautious running the pumps in parallel, one for hot and one for cold unless the shower is a thermostatic one. Otherwise, if the cold failed for some reason, you'd be pumping hot only to the shower, with a risk of scalding. With a single pump if the flow fails the pump shuts down both cold and hot.

VERY good point

 

[europhil]

VERY good point

it is a good point, but it is a positive feed, so the cold will still flow under gravity.
So i'm not too concerned about that.

What i am concerned about is the fact that i can't work out what preasure increase i'll get with my big plan?:confused5:

 

[JCplumb]

Surely 2x1.5 in paralell will give 3 bar or pretty close to it. In series it would still be 1.5 bar but in paralell you'd add them up.

 

[Howsie]

Remember not to give him too much water...

 

[europhil]

Surely 2x1.5 in paralell will give 3 bar or pretty close to it. In series it would still be 1.5 bar but in paralell you'd add them up.

That's what i thought, But then i thought, narrrrrrrrr can't be that easy i'm missing some mad calculation.

 

[PlumbBobBob]

what sort of shower head is being supplied by the pump/s?

 

[europhil]

what sort of shower head is being supplied by the pump/s?

There's two. One is a fixed head about 8"x6", and the other is a standard one on a hose. You can only use one at a time.
The bath is also on the same feed as the pump.

 

[Ray Stafford]

Maybe I've got my head on back to front, but I would expect 2 in parallel to increase the flow (subject to the pipe sizes being big enough) but not the pressure?

 

[PlumbBobBob]

what is flow like from each one in comparison? i would expect the overhead one to be less powerful because of it's size.

 

[europhil]

what is flow like from each one in comparison? i would expect the overhead one to be less powerful because of it's size.

The flow on the overhead one isn't as powerful as the other, But like you say, That's what you'd expect. I get about what i'd expect if i was running them off a decent combi. Not super powerful, But not terrible.
So i'm trying to get the best i can without spending anymore money.
I just can't bring myself to buy a 3 or 4 bar pump, Then find out he's still not happy with this or that.
I think i'll give the two pump idea a go. If he's not happy, Then i remove the new pump and walk away.

 

[Howsie]

Should increase both because pipe size is easily the limiting factor here. IMHO.

 

[europhil]

I should have said earlier. it's all on 22mm until a few inches from the shower/tap connections.

 

[sgph]

fit the pump you were asked for then thats the job done. if they want more then that should have been stated. if still more is wanted its at there expense. bend over backwards for him and he will have you even more next job!!!
stick well within manufacturers instructions with the pump as if he is a bugger of a customer you may find yourself on the wrong side of a court room if ANYTHING goes pete tong!!!!!

also remember .... increased flow rates mean increased storage tank sizes!!!!!!