Very poor output from taps and shower

[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.

 

[village idiot]

I would still suggest that you go through a process of elimination: honestly, my guess is that it could be one of TWO things (OK, may be 3?).
1) Either pump related, of
2) Air lock.
I'd bypass the pump and see if I get a steady flow of water at the hot taps, even if the boiler isn't firing. After all, you used the system in the past with no pump. That test will determine if you have an airlock. If water flows freely continuously, then tue pump must be a culprit. 3rd option would be pipework but that is unlikely.

 

[Nick77]

I would still suggest that you go through a process of elimination: honestly, my guess is that it could be one of TWO things (OK, may be 3?).
1) Either pump related, of
2) Air lock.
I'd bypass the pump and see if I get a steady flow of water at the hot taps, even if the boiler isn't firing. After all, you used the system in the past with no pump. That test will determine if you have an airlock. If water flows freely continuously, then tue pump must be a culprit. 3rd option would be pipework but that is unlikely.

Thank you VI.

I agree your method would lead to a diagnosis regarding the pump, air-lock, pipes or possibly boiler (divertor valve/heat exchanger, anything/everything else has been mentioned). It's obviously a process of elimination. I can't do this myself and the 2 plumbers who have been here are not coming back. The guy who fitted the pump had another appointment and had to leave and I haven't been able to contact him for a week. The second, after a series of checks, said he was able to dismiss the pump - his assessment was: air-lock - but said he couldn't help.

This is a two-bedroom flat. I can't believe it's such a complex problem. However, timing is the other thing. Plumbers are busy in December..

I appreciate the time that you and other contributors have taken to help with this.

 

[village idiot]

You are welcome Nick. I'm hoping you get this resolved before the festivities kick in. In reality, the plumber who fitted the pump should attend and try his best to resolve the issue. But seeing he left for another appointment and hasn't made contact in a week, I'm suspecting he will avoid coming back there. December is a busy month but that's no reason to not address "problems" arising from jobs you did?

 

[Nick77]

To VI, Rocketman and all on this forum,

Best wishes for a successful 2016.

 

[kay-jay]

You say the plumber isolated the pressure vessel to rule that out?

Describe the vessel. It may be that the vessel is an accumulator that has lost its charge and therefore not delivering the necessary flow