Shower pump problem

[ozzy]

Hi all,

I fitted a new mixer shower, which I advised the customer would probably require a pump.
After using shower customer asked me to fit a pump.
I supplied and fitted a pump and all was working fine.
I got a call from the customer to say pump not working no water.
Disconnected pump and connected up pipes and still no water. I removed the shower valve and had water out both pipes.
I removed elbows off shower valve and blew into the elbows to ascertain if the check valves were opening correctly Cold was ok hot failed to open. I freed the valve and refitted the valve and checked for flow of water which was ok.
I refitted pump and all was working ok.
Customer called that evening to report shower not working again.
If the check valve on the hot side has stuck again would that prevent the pump kicking in at all?
Is it a faulty pump or shower valve?

 

[IDCHAPPY]

Usually no flow = no pump run so that could be explained by a sticking check valve

 

[gassafe]

Is there enough flow to activate pump? What's the head of pressure? Is it up & over pipework?

 

[Jimbobber]

If both sides are gravity fed, no check valves are required! As there is no risk of backflow. As said the flow may not be enough to lift the float switches inside the pump. Perhaps the cwsc is not large enough to cope with the increased usage of the shower. Read the pump manufacturers manual to ensure correct installation. Hope this helps!

 

[ozzy]

Thanks.
The cylinder is on the 2nd floor, The shower is on the 3rd floor with the cold water tank in the roof. There is about 18" from the base of the tank to the top of the fixed shower head. Without the pump and the shower valve fitted the water flows well. With the valve on, the water only trickles out the fix head and is better on the head on the riser. The pump is on the floor at the base of the shower in a cupboard. Could it be a faulty shower valve or pump? would I need to change it to negative head pump.
Thanks Ozzy

 

[gassafe]

If both sides are gravity fed, no check valves are required! As there is no risk of backflow. As said the flow may not be enough to lift the float switches inside the pump. Perhaps the cwsc is not large enough to cope with the increased usage of the shower. Read the pump manufacturers manual to ensure correct installation. Hope this helps!

most thermostatic showers come with built in mini check valves tho, they can be removed by undoing the little circlip... Not sure if manufactures would approve tho?

 

[gassafe]

And stop fitting flowmasta shower pumps... Do you enjoy callbacks or something?? Lol

 

[ozzy]

Thanks
The cwsc should be ok its a fare size. Its the first and the last I will ever fit. Will change the pump next week when I go back. Thanks again for your help.
ozzy

 

[Jimbobber]

most thermostatic showers come with built in mini check valves tho, they can be removed by undoing the little circlip... Not sure if manufactures would approve tho?

So long as it did not compromise the function of the mixer, it would not breach water regs for a balanced gravity fed or pumped gravity fed shower mixer. Doesn't require retention ring on hose either.

As for what manufacturers would say, who knows.

 

[Paulus]

It sounds like you don't have enough flow to activate the flow switches as Jimbobber says. Try turning on the shower whilst connected to the pump and running a magnet up and down at the point where the flow switches are located on each side of the pump. If this activates the pump then you know the answer is a negative head pump.

 

[ozzy]

Thanks It was my first and last flowmasta I will fit lol What is a good make? fitted salamander pumps a few times. If I remove the check valve does this invalidate the guarantee? I've found a few magnet so will give this a go before buying a negative head pump.

 

[PlumbBobBob]

Thanks It was my first and last flowmasta I will fit lol What is a good make? fitted salamander pumps a few times. If I remove the check valve does this invalidate the guarantee? I've found a few magnet so will give this a go before buying a negative head pump.

stuart turner every time

 

[Jimbobber]

Thanks It was my first and last flowmasta I will fit lol What is a good make? fitted salamander pumps a few times. If I remove the check valve does this invalidate the guarantee? I've found a few magnet so will give this a go before buying a negative head pump.

You need to install shower pumps in the correct way to avoid air that will damage a pump. You need a dedicated feed from the CWSC for the cold down in 22mm. You need a dedicated feed from the cylinder for hot in 22mm via either an Essex or Surrey type flange. You can also come off the main hot feed pipe from the top of the cylinder, the main feed must be between 30 and 60 degrees rising toward vent pipe, with a Tee pointing downward to allow air to pass up to the vent pipe and not down to your pump. Although cheaper to use a few fittings I don't really like this method. You'll probably not get an Essex flange in without removing the cylinder first. Id use a surrey flange personally. Few more quid but easy to do with everything already in place.

Also sounds like you do need a negative head pump because 18" is naff all above the shower head. Also the cylinder being so low will be working against your head pressure on the hot side. If you do it like this it will never be a problem. but the manual will state minimum needed flow rate required for pump to work. It could be a blocked shower mixer but you don't appear to have correct distance below CWSC to shower head.

Stuart turner pumps all the way, techflow and salamander also pretty good.

 

[Jimbobber]

Also of course do not overlook the mixer pressure requirements.

 

[AlanWright]

I have been looking at flow switches for a while now when I developed my own flow switches for the Shower Power Booster. A good switch should activate at 0.8 litres a minute or below. You could check what flow you are getting and find out what the minimum flow they require to activate their flow switch - it might just be a faulty flow switch that is giving you the problem?

 

[ozzy]

I switched on the shower and then ran a magnet up the pipe by the flow switch and the shower pump started straight up so from above advice a negative pump it is ?
Thanks for all your help

 

[Plumbstar Tom]

Could have turned the pump upside down instead of going to the expense of a magnet

Can you increase the height of the CWST?

 

[ozzy]

No there is not much room above the tank to lift it. The magnet just had to find it in my sons room. Will have to check the pipe work is ok

 

[WHPES]

Could the pipes be airlocking? Any upward loops between the cylinder to the shower where dissolved air can collect?

Remove the check valves from the shower.

 

[Paulus]

Could have turned the pump upside down instead of going to the expense of a magnet

Can you increase the height of the CWST?

How do you turn a pump upside down whilst plumbed in?

 

[Ray Stafford]

How do you turn a pump upside down whilst plumbed in?

Flexis. great big long juicy flexis.

 

[gassafe]

All good plumbers have some of these on the van surely ;p


Flexible Tap Connector 15mm x 3/4" x 900mm | NoLinkingToThis

 

[Ermintrude]

Wow can I use them on combi swaps? Do they do a flex for the flue?

 

[Ray Stafford]

All good plumbers have some of these on the van surely ;p


Flexible Tap Connector 15mm x 3/4" x 900mm | NoLinkingToThis

You don't want to know how many thousands of those we sell. Its scary.

 

[Ermintrude]

Thought you only sold to trade not DIY?