Very poor output from taps and shower

[Nick77]

Hi,

I have an ongoing problem with the water flow from my mixer taps and shower. Only the flow rate from the mains-supplied kitchen cold tap is acceptable. Over the last 2 - 3 months the output from the other mixer taps has gradually decreased and it seemed likely that my booster pump had developed a fault. When the taps are turned on there is a reasonable - not great - output fro about a minute and then it reduces rapidly. Turning on 2 taps leaves barely an output from either. Flushing the loo also cuts out the flow from a running tap.

A new variable speed pump was installed last week but there this hasn't improved things. Another plumber spent all afternoon today trying to remedy the problem without success, which was as frustrating for him as it is for me. He thinks there is a massive air-block but can't see how to resolve it. He is going to ask around to see if any of his fellow plumbers have had similar experiences.

I now think it possible that there was nothing wrong with the old pump but can't be sure.

If anyone can advise on this it would be great to hear from you.

Many thanks and regards,

Nick

 

[ShaunCorbs]

are the problem taps mains feed or tank feed

also hot or cold or both?

 

[Nick77]

Thanks for replying Shaun.

The mains feed is fine.

I'm on the top - fourth floor - of a block of flats and the non-mains supply is from a communal tank on the roof. The fault is with both hot and cold outputs from the mixer taps and shower unit. If I run more than one tap the flow rate is too low to ignite the boiler. It just fires when a single tap is running.

 

[ShaunCorbs]

Thanks for replying Shaun.

The mains feed is fine.

I'm on the top - fourth floor - of a block of flats and the non-mains supply is from a communal tank on the roof. The fault is with both hot and cold outputs from the mixer taps and shower unit. If I run more than one tap the flow rate is too low to ignite the boiler. It just fires when a single tap is running.

are both mixer taps/shower on tank/do you know

 

[Nick77]

The feed to the shower and mixers in the kitchen, bathroom and cloakroom come from the communal tank on the roof via my pump. I think this is also true for the combi boiler, WCs and water softener device. I don't have my own dedicated break tank. I hope this helps.

 

[ShaunCorbs]

The feed to the shower and mixers in the kitchen, bathroom and cloakroom come from the communal tank on the roof via my pump. I think this is also true for the combi boiler, WCs and water softener device. I don't have my own dedicated break tank. I hope this helps.

thats ace right do you have a pump to your flat or is there a main one in the plant room and any other tenants have this problem?

 

[Nick77]

I have just replaced a 3.0 Bar pump with a variable speed type. The pressure Set Point is 3.0 Bars with a max pressure delivery of 5.0 Bars. This should provide a second-to-none flow rate but doesn't.

The first pump was installed about 6 years ago and was the solution to my low pressure problem. I'm not sure if other top-floor flats have this problem or have installed pumps but I had no alternative to overcome the poor flow rates.

 

[ShaunCorbs]

and the pump is one for boosting incoming mains/tank fed? and not a normal shower one

 

[Nick77]

Not a normal shower one. Also, it doesn't boost the mains supply, only the feed from the break tank on the roof, which branches off to my flat first. The low rate into the pump is good.

The new pump is a DAB E.SYBOX MINI. The previous pump was a Stuart Turner Monsoon extra Negative Single 3.0 Bar.

 

[ShaunCorbs]

Not a normal shower one. Also, it doesn't boost the mains supply, only the feed from the break tank on the roof, which branches off to my flat first. The low rate into the pump is good.

The new pump is a DAB E.SYBOX MINI. The previous pump was a Stuart Turner Monsoon extra Negative Single 3.0 Bar.

thats fine has it been piped as mis state and there no valve half shut is there this might help if not might be worth a ring to dab tech

[video=youtube;DQsx-nLJDx4]https://www.youtube.com/watch?v=DQsx-nLJDx4[/video]

 

[rpm]

I`ve found DAB to be most helpful in the past.

 

[Unregistered]

The plumber today checked everything; he was very thorough and disappointed that he couldn't resolve it. He's sure it's a major air block that couldn't be fixed by running the the hot and cold miser taps with the spout covered. Previously, I ran all the hot water taps for about 90 mins to deal with the air-block assuming that's what it is. Not sure what else it could be after the pump and fittings were checked.

I've tried DAB tech and they can't fathom it either.

 

[Unregistered]

Hi rpm and thanks for writing. I agree, DAB offer an impressive all-round service and spent a great deal of time thinking up things to try. I'm sure their pump is fine.

 

[ShaunCorbs]

Hi rpm and thanks for writing. I agree, DAB offer an impressive all-round service and spent a great deal of time thinking up things to try. I'm sure their pump is fine.

have you got a pic of where the pump is and log back in plz

 

[rocketmanbkk]

I don't think it's air locked, only going by what op says. He's the first flat to get fed from the tank. If air then it would either splutter out or stop fully.

Can the op undo pipes from taps & see what pressure is coming out of pipes. That will then tell you if taps at fault, if not & the pump is doing its job there might be crap in the feed pipe.

What exactly has the plumber done today?

What checks & tests?

 

[rocketmanbkk]

Just to clarify for myself, the cold feed from communal tank feeds your hot storage tank? The pump then, from your hot feed to taps pumps water around flat which has poor pressure & gets worse after taps are left on?

 

[Unregistered]

I can't upload an image as I haven't a camera now.

Hi Rocketman and thanks for contributing. There is sometimes a bit of a splutter when I turn the taps on. Normally, the water flow at a reasonable, though by no means good, rate when the taps are opened and the output starts to slow soon after.

My plumber disconnected the feed pipe and checked the flow rate into the pump. He checked the filters and looked fro any sludge or debris. He did the same on the output side. I have a pressure vessel above the pump. It was installed along with the previous pump 6 years ago to serve as a reservoir (5 gallons) so that briefly turning on a tap or flushing the loo wouldn't immediately activate the pump. The plumber isolated the pressure vessel so that was eliminated from the list of possibilities. He also disconnected the flexible hose from the bathroom mixer - no change, so probably the taps are fine.

I don't have a hot water storage tank; I have a combi boiler. The communal tank feeds into my pump.

Thanks again everyone.

Yes, the flow rate deteriorates with the taps running.

I think it's probably a question if someone having had a similar experience and found a solution.

 

[rocketmanbkk]

Mmmmm....

 

[Unregistered]

Just to clarify for myself, the cold feed from communal tank feeds your hot storage tank? The pump then, from your hot feed to taps pumps water around flat which has poor pressure & gets worse after taps are left on?

Hi again Rocketman (and everyone else),

Your assessment above is accurate. The mixer taps have poor pressure and gets worse with the taps running. This describes the the cloakroom hot water mixer still and the hot tap in the kitchen. However, this morning, I noticed the mixer tap in the bathroom has no output at all if the hot supply is fully turned on.

Can anyone help? It would be greatly appreciated.

Thank you.

Nick

 

[village idiot]

Nick, sorry to hear about your problem. BUT, you need to Log back into the Forum if you want to continue this ''discussion''. Failing that, one of the Forum MODS may decide to close the post completely.
From what you have mentioned, it seems like you have an air lock issue somewhere? Why the plumber can't find it is the issue? Instead of him using hot and cold to sort it out, he should use the mains fed water to kitchen sink to blast that back to the tank and see if it clears. The flow rate from hot & cold taps are already poor, so how is using them to clear air lock goint to help?
If pump can be issolated, then the hot is blasted and checked, then same done for the cold, this will determine if airlock is resolved or not. Pump can then be connected and tested.
Personally, I would remove the pump completely make up hot and cold connections to system and see if the water flows freely & evenly (even if at a poor rate). That will give me an indication of whether an airlock exists.

 

[village idiot]

The plumber today checked everything; he was very thorough and disappointed that he couldn't resolve it. He's sure it's a major air block that couldn't be fixed by running the the hot and cold miser taps with the spout covered. Previously, I ran all the hot water taps for about 90 mins to deal with the air-block assuming that's what it is. Not sure what else it could be after the pump and fittings were checked.

I've tried DAB tech and they can't fathom it either.

Using the hot and cold mixer tap is a NO BRAINER in this situation

 

[Nick77]

Thank you for your comments VI. i's starting to think I should borrow your username or one equally expressive, as I can see only too well how dumb I must sound.

Previously, I ran all the hot taps for about 90 mins to clear the air-block. It seems clear to me that back-blasting is the way to go or, at least, worth trying. It would also be straight forward to bypass the pump. Yesterday, the plumber opened the cold (mains-fed) tap in the kitchen and covering the shared spout with his finger opened the hot. The pump was still in the circuit. It probably seems obvious to all the professionals on here but do you have a method to explain the back-blasting procedure in detail to the next plumber who is brave enough to attempt to solve this.

Forum moderators, please keep this thread open for a while longer.

Thank you.

 

[Nick77]

just thought I would add something suggested by a plumber today.

1. Shut off the supply from the pump to the taps.

2. Open all the hot taps until drained.

3. Use a vacuum cleaner - minus the bag - to draw all the air from the system ie between the pump and the taps. The idea is to place the nozzle or hose under one of the taps.

This advice was given in good faith and I was wondering if it has worked for anyone. I can see that the water in the U-bends might be sucked up but would it clear the air-lock?

 

[TVP&H Ltd]

Is the pump running when the taps are open.
If YES, then its a supply flow rate problem, because the pump would push any air out of the open taps.
If NO, then it's a pump fault (unlikely).

Why was the pump changed in the first place?

 

[Nick77]

Is the pump running when the taps are open.
If YES, then its a supply flow rate problem, because the pump would push any air out of the open taps.
If NO, then it's a pump fault (unlikely).

Why was the pump changed in the first place?

Hi, the pumps runs when the kitchen and bathroom hot or cold mixer taps are open. In the bathroom there is no output from the hot tap (also a mixer) but it runs when the cold tap is open. there is a poor flow from the shower but this will cease if a top is opened. In fact, only one hot tap can run at a time.

This started about 3 months ago just gradually deteriorating. I changed the pump because I was advised that the pressure switch needed to be replaced and although it was installed only 6 years ago, spare parts are no longer available. The new pump is a variable speed model and, as you guess, works well. The flow rate to the input is good and the output is also fine.

Someone has suggested that it might not be an air-lock but a problem with my combi boilerin that it isn't supplying enough water but this doesn't really explain why the bathroom tap alone has no hot water output at all.

Many thanks for replying to this thread.