Hot water taps problem All aspects of plumbing questions and answers, help, tips and information

[dale_w]

ive got a problem with my hot water supply, for a long time the hot water tap in the bath has lost pressure and now comes out at just a trickle but all the other taps were fine, but for the last few weeks all the hot taps have gone the same way and the one in the kitchen needs to be turned as far as it will go just to get a trickle! does anyone have any ideas what this could be? the bath has seperate hot and cold taps but the rest have mixers. im getting really frustrated with this so any help would be appreciated!

thanks,

[htg engineer]

Depends on system type.

Sounds like you need to replace the ballvalve, as the flow rate is greater from the bath tap, you will notice it hear first is the ballvalve isn't filling the tank as quick as the taps are emptying it.

htg

[dale_w]

the ballvalve was changed only last year is there any way of adjusting it rather than getting a new one?

[Dave From Leeds]

Dale,

If you are only getting a trickle from the hot taps as soon as you turn them on, it suggests to me that your cold water storage tank is not filling up. Have a look in the top of the tank. It might be that the float on the ball valve has somehow got wedged against the inside tank wall or something.

Alternatively there may be a blockage in the supply pipe to the ball valve or in the valve itself, preventing the tank from filling.

[dale_w]

the hot water in the bath comes out fine for a couple of seconds then it slows to a trickle

[Dave From Leeds]

It seems likely as I said that there is very little water getting into your cold water storage tank. Are the cold water taps OK, particularly the kitchen sink one? I don't think the fact that all other taps than your bath are mixers will have any bearing on your problem.

I think it will still be worth your while checking out the tank as I suggested last night.

[dale_w]

all the cold taps are fine, its only the hot taps that are the problem, ill have a look at the tank and see if its that causing it

[richardm5125]

i had a similar problem a few years ago, same system as yours it sounds.
hot water cylinder , fed by cold water storage tank. Hot water taps started to slow down especially hot bath tap. after some trial and error, found it was the gate valve between cold storage and hot water cylinder. It hadn't fully opened last time it was used. gate valves and stop taps have a tendency to
do this over time, limescale and rubbish builds up around them. So gate valve was only partially open, any debris in cold storage which would normally flow through was getting trapped, only to compound problem. Fitted new gate valve, only few quid problem solved. Hope this helps good luck.

[richardm5125]

just read your other replys, not quite sure about these, sorry guys if i'm being a bit of a know it all, I certainly aren't. Although I'm pretty much a logical person. and i hate to hear about people's frustration over something that can be quite simple, It's happened to me many times. Anyway down to business, can't really see how it can be ball valve in cold storage, unless tank hasn,t filled up at all, first check to see if tank is full, this will surely give you
a good few minutes of hot water, until it runs dry. As said in previous post
must be a restriction in pipes, more than likely a gate valve, happened to me . Water will trickle at first, taking what little water has seeped past gate valve
and filled up pipes. Also kitchen tap is slightly better, as pressure there is a little more, and is just managing to suck some more through. Please let me know if this helps.

[dale_w]

im going to check it now ive been a bit snowed under and been putting it off, hope its something simple.

[dale_w]

ok so i just had a look at the ball valve and it looks fine when i run the taps the tank fills up, i checked all taps and the only ones where the tank fills up less is the hot taps, because theres less water emptying so i dont think its the valve, i tried holding the ball valve down so the tank fills up and no change, i checked the gate valves and when i turn them on again the same thing happens water runs fine for a few seconds then slows to a trickle. i dont know what else to try looks like im gonna have to call in a plumber and pay the ridiculous charges!

[plumbbob]

Before you call a plumber, you may like to try three things.

Firstly, check the water outlet to the cylinder in the header tank as it is not unknown for debris, plastic for example, to be blocking it.

Next, are you sure the gate valve is opening and closing fully? They are devils at corroding and can even block. Are there three or so full revolutions between fully closed and open?

If this fails, try putting your thumb over the end of one of the mixer taps. Turn the hot fully on then slowly open the cold. The idea is to force water back up the hot pipe to shift any blockage. Of course if the blockage is limescale, you may get wet.

If water flows use as much pressure as you can stand and continue for 10 seconds.

[ro32x]

Here is a thank you to a 2 year old post from plumbbob:

I have the same problem with a intermittant slow hot water trickle.
Sometimes its fine for a week or so.
Today it slowed to almost nothing.
I know nothing about plumbing so was looking for a non tecnical fix, so i tried the trick from the previous post:
-----
If this fails, try putting your thumb over the end of one of the mixer taps. Turn the hot fully on then slowly open the cold. The idea is to force water back up the hot pipe to shift any blockage. Of course if the blockage is limescale, you may get wet.
If water flows use as much pressure as you can stand and continue for 10 seconds.
-----
Worked very well thank you.
I'm guessing this is only a short term fix, so will probably need a flush out from a professional sometime???

[Dave From Leeds]

ro32x

Whether or not it's a short term fix depends what has caused the airlock in the first place. If it's due to a one-off event, such as work done to the system then the chances are that it will be a "permanent" fix. However, if the airlock has occurred due to a gradual ingress of air for which the source has not been identified and eliminated, it could well occur again, the time interval depending on how quickly the air is getting in.

[DIY Radlett]

This is a great post, and my hot water tap to the bath now runs freely. Thanks to all who provided advice on the airlock. I'll offer some refinements to the process that made it easier and more effective.

I have mains pressure water throughout, as I've a Boilermate, but this will probably work with any airlock.

First, my thumb was too small and too weak to contain the mains cold water pressure, and I got spray all over trying to contain the tap. I realised, however, that I could fix the problem using the shower hose. I unscrewed the hose fitting, put a five pence piece behind the washer, and screwed the hose back on. Then I toggled to the hose using the lever, and followed advice about turning on the hot and then the cold to full mains pressure.

The advantage of the toggle method, was that I could check progress by toggling back to the filler tap. And it was easy to toggle back and forth as I repeated the process. It was better, but not back to full after three tries.

Then I realised that the sink was on the same feeder pipe for hot water, but had full hot water pressure. So the airlock was between the bath and sink. I turned the sink hot tap on to draw hot water pressure from the cylinder, and with the bath tap at full cold mains divert into the hot bath pipe, the airlock should have been forced back toward the sink. Presumably when it hit the up-pipe at the sink, it must have released.

Anyway, between these two tricks, my hot water pressure is restored to full and I am very grateful.