Shower Pump problem

Makhaira

Makhaira

Makhaira

Soldato
Joined
23 Nov 2007
Posts
4,969
Location
Lancashire, UK
Just installed my new shower and I thought I was therefore up and running, but clearly not.

I've had a Grundfos Niagara 1.5bar pump installed, with a York valve coming off the top of my tank for the hot water feed, and the cold feed coming from the tank in the loft.

Having primed the pump, it ran without problems. For about 40 seconds. At that point I started to get a lot of cavitation noise, so I turned it off.

Following several short runs of it, it always seems to start being noisy after approx 40 seconds. The manual recommends a max hot water temperature of 60C to avoid pump noise, which is what my tank was set at, so I've dropped that to 50C to see if it helps.

The worry in the back of my head is whether it's possibly down to the hot cylinder being drained faster that it's replenishing, meaning that the pump pulls in air? If that's the case, then I'll get the plumbers back, but it's a headache I could do without!

Any and all thoughts/suggestions welcome please, been dealt a bit of a blow since I was looking forwards to a shower in my own house tonight!

Cheers.
 
That Grundfos pumps has a maximum 55 litres/(12 gallons) a minute flow rate with either 15mm or 22mm according to specs.

Sounds like your drawing in air.:(

I would phone the plumber & explain the cavitation noise problem first, & see what he think is wrong.
 
Last edited:
:(. Just checked what was fitted and there's definitely a surrey flange in the top of the cylinder, and no sign of any leaks from pipework. Is there anything else I could try or check before I call the plumbers back? Don't want to get a call out charge if it's not their fault!

Cheers.
 
I've spoken to the plumber, he thinks it might be because he's tapped into the cold feed to the hot water cylinder rather than taking a new feed direct from the cold tank. Would this explain it? I'm going to make sure I'm in when they do the work so that I can ensure it sounds right before they leave.
 
Makhaira said:
I've spoken to the plumber, he thinks it might be because he's tapped into the cold feed to the hot water cylinder rather than taking a new feed direct from the cold tank. Would this explain it? I'm going to make sure I'm in when they do the work so that I can ensure it sounds right before they leave.
Click to expand...

Very plausible, I certainly wouldn't have done it his way, it is better to take direct feed from header tank as it's around anything up to 18 gallons capacity,& as you want a hot shower, hot/cold mix ratio, so there less chance of emptying it, as it continually filling during use.

There is a formulas for working out for tank fill rate & discharge/ flow rates with pipe sizes, but it eludes me.

EDIT: This explains things very well, see this linky: http://www.johnhearfield.com/Water/Water_in_pipes2.htm
 
Last edited:
Thanks, I'm on my phone atm so I'll read that this evening. I presume the rate of cold input to the hot tank dictates how quickly you can pull hot from the top of the tank? Err fore by splitting that single feed I'm guessing that I empty the cylinder a bit, thereby pulling in air from a gap at the top of the cylinder?
 
Just been reading up on surrey flanges (they said it was a York, which I understand is just a Surrey with an adaptor?). It also appears that the shower feed is connected to the wrong part, as the shower feed comes from the top of the flange, not the side! Grrrr.
 
Last edited:
Me too, but unless there's a variant where the shower feed is meant to come off the top instead of the side, that's not the case!
 
Makhaira said:
I've spoken to the plumber, he thinks it might be because he's tapped into the cold feed to the hot water cylinder rather than taking a new feed direct from the cold tank. Would this explain it? I'm going to make sure I'm in when they do the work so that I can ensure it sounds right before they leave.
Click to expand...

If he's done that then he's not a plumber to be trusted, simple as that. That's obviously going to cause problems because the same cold supply is trying to replenish the hot cylinder as well as feed your gushy shower.

We had all kinds of fun trying to get a shower pump installed correctly and in the end I just did it myself with a Techflow Techflange, which curves upwards to get the hottest water to the death, and a dedicated 22mm feed from the cold water tank in the attic, both of which meant that the shower pump worked perfectly. Techflange:

img8242k.jpg


olDAiCFl.jpg

(Ignore the PTFE on the thread please :p)

http://www.ukplumbersforums.co.uk/b...-fit-techflange-essex-flange-shower-pump.html

We had a Grundfos Watermill but it expired pretty quickly, because the 'plumbers' had teed off all kinds of crazy places, meaning that air was being drawn in off the vent pipe. Oh and they also connected the water inlet pipes to the outlet on the pump, so you might want to check for that too :p. Skillful bunch. Why people don't bother reading the instruction manuals...

You got pics of your setup?
 
Last edited:
No pics at the moment, all my tiling gear is infront of the airing cupboard at the moment!

I'm more than a little cheesed off, but playing it nicely nicely at the moment since I obviously want them to come back and make good on their work. In the meantime, I can only run the pump for about 30 sec or so before I get air entering it, so I'm trying to avoid using it to as great an extent as I can.

The thing that has really irritated me is that this bit of the bathroom refurb I didn't do myself as I wanted to get a proper job done of it! So much for that sentiment!
 
I don't trust anyone now. Even tradesmen recommended by friends or family have sometimes proven to be sub-standard, often revealed a couple of years down the line when it's too late. Or maybe I'm just super picky?!

Anyway, I would switch the pump off tbh as if it breaks it'll be expensive, and the more the pump runs with cavitation the more damage will be done. I presume they've at least fitted a separate switch for the pump?
 
Robbie G said:
I don't trust anyone now. Even tradesmen recommended by friends or family have sometimes proven to be sub-standard, often revealed a couple of years down the line when it's too late. Or maybe I'm just super picky?!
Click to expand...

Nope.
Your paying good money, you expect a quality job in return.
I never have trust a tradesman,seen a few cowboys in my time.
 
Last edited:
You must log in or register to reply here.
Back
Top Bottom