Header/expansion tank filling with hot water

[Ziderman]

I have a hot water cylinder which is heated by te gas boiler (not a combi) and yesterday the overflow started running although only slowly. It has run overnight despite the heating being off.

I'm sure its the hot water expansion not the header tank for the rads.

I've been into the loft and the tank is full, there doesnt appear to be cold coming in, the ball cock is floating and not even dripping. THe water is definitely warm/hot.

The fat pipe at the bottom of the tank appears to be letting the water is almost like its being pushed into the tank you can just see the water swirling.

Any help I'd be grateful.

Thanks in asdvance.

 

[Fluffster]

You may have a hole in your coil within the cylinder forcing water up through your cold feed and then overflowing.

Pete

 

[seco services]

more likely cold mains crossing over to gravity hot through a mixer tap or shower valve.

locate and mixer or shower that has gravity hot/mains cold ie kitchen.
and isolate that mixer.
useally a faulty non return valve or stuck open.

 

[Ziderman]

Its sounds like the cross over from cold to hot as the hot water is being forced out the top leaving us with luke warm rather than hot water. Would the same apply with a shower pump?

We have had soime issues recently with the pump not starting when you start the shower. I imagine through low water pressure, that seemed to clear yesterday when this leak started.

Sounds like I need someone in rather than trying to attempt a fix myself though.

It never rains but it pours!

 

[seco services]

whats the shower pump ?
a shower pump should be equal pressures ie hot from cylinder cold from the storage tank.

 

[Ziderman]

You aren't going to like this, there is no cold tank it's direct feed.

I have switched the cold water off at the main and it has stopped the flow which kinda proves its the issue of cold getting nto hot.

Just so you know the setup, the direct feed comes in downstairs where there is a mixer in the bathroom and one in the kitchen, these appear fine.

There is also a mixer on the bath upstairs that appears fine too (this is the bathroom where the shower and pump are). The pump was installed as there is only a small head between the hot tank and the shower head, in fact there is none, when you switch the shower on you have to rest the shower on the floor of the bath to get the pump to kick in. The hot tank being on the first floor level with only a header tank in the loft as high up as it will go.

The pump was installed because there was literally no power at all in the shower it dribbled so no good for man nor beast.

Only the hot goes through the pump before meeting the cold at the shower mixer embedded in the wall.

 

[seco services]

have you a pic of your hw cylinder etc

you state.
there is no cold tank it's direct feed.

The hot tank being on the first floor level with only a header tank in the loft

what ones true ?

to me it sounds like you have an indirect system with hw cylinder on first floor, cws in loft.
shower pumped hot mains cold.

 

[Ziderman]

You're being very patient with me, thanks.

The hot water cylinder is the same as the blue one in your previous post. In the loft I have two tanks, one small one which feeds the heating side (I know this cause it's the one I emptied when I replaced the heating pump and the three way valve), and a larger one which is the one overflowing and has warm water in it. The ball cock is defintely floating OK and no leaks from the inlet. There also seems to be an expansion pipe that comes in at the top of this tank but that is dry, the water seems to be coming in through the thicker pipe at the bottom.

The house is a chalet style so the bathroom upstairs is on the same level as the shower and the insulated hot water cylinder (not tank, sorry). There is no cold water tank, and yes the shower would get hot if someone pulled a flush!

not sure what you mean by cws hope I've answered it with the above.

 

[Ziderman]

Having now put the cold water back on the overflowing has started again, so it looks more and more likely that there is a crossover between hot and cold, probably in the shower mixer, bugger!

What can I do?

 

[HERTS P&D]

Fit non-return valves on the supply pipe work to the shower.

Andy

 

[seco services]

have you any isolation valves on the shower pipework, or pump ?

 

[Ziderman]

Yes, have switched off the cold feed to the shower mixer and it seems that may have done it. So any ideas how I fix the problem in the mixer, bearing in mind it's in the wall!

Is it a case of fitting the non-return valve on the hot side (the pipes to the mixer are embedded in the wall too, I can however get to the pipes where the isolation valves are (compression fittings) just after they split from the bath feeds, any good?

Thanks so much for the advice, always learning........

 

[seco services]

yes fit one on the hot log as its after the pump.
i take it the hot bath tap is pumped as well ?

 

[Ziderman]

Right I have isolator valves either side of the pump. I take it then if I replace the isolator vale on the 'out' side of the pump with a non-return valve then it would stop this back flow and if I needed to replace/repair the pump then the non-return valve would stop the water coming out when I take it off.

Regarding the bath tap no it's not pumped. Because the tap is lower than the shower head it seems to run OK albeit a bit weak. It would take a long time to fill the bath though.

Don't bother trying to fix the mixer then?

Is this a common problem?

 

[seco services]

Right I have isolator valves either side of the pump. I take it then if I replace the isolator vale on the 'out' side of the pump with a non-return valve then it would stop this back flow and if I needed to replace/repair the pump then the non-return valve would stop the water coming out when I take it off.

i would still fit the isolation valve.

Regarding the bath tap no it's not pumped. Because the tap is lower than the shower head it seems to run OK albeit a bit weak. It would take a long time to fill the bath though.

whats this bit then about the pipes split from the bath ?
(where the isolation valves are (compression fittings) just after they split from the bath feeds,)

[quote}Don't bother trying to fix the mixer then[/quote]
that would be a better solution if you can strip it down as the non returns means the mixer will have to be disconnected in the wall and come out to free the valve.

what make/model mixer is it ?

Is this a common problem?

quite common.
but then its not ideal to have you mixer on mains cold pumped hot.
work better on equal pressures.

whats the height distance from your head to the base of the cws in the loft ?