Overflow from hot water

Is the water flowing from the pipe hanging over the water tank?
Or is the water just flowing out of the overflow pipe to the outside?

If it is from the pipe hanging over the tank, then the flow of water in the system is following the path of least resistance, in this case, straight to the feed and expansion tank in the attic.
My suggestion would be to have your Radiators / Hot Water Cylinder checked and balanced first, ensuring that there is no unnecessary resistance on the radiators and hot water circuits.

Is it a steady flow only when the heating is on, or does it continue to drip occasionally when the heating is off?

John.G wrote: »

Also, in case there is a hole in the cylinder coil and if the level in the cold water storage tank is higher than the level in the (small) F&E tank, check if the cold water storage tank ball cock is making up with no demand for either domestic hot or cold water.

Thats what I was thinking as well.
In the first post the o.p. said that a new cylinder (immersion tank?) had been installed, but that doesn't mean it doesn't have a leak on the coil.
I've had issues with a few new cylinders, so I definitely wouldn't rule out the possibility of a faulty coil.

Your electric shower is a completely separate issue to the water dripping from the tank overflow.
Probably best to have a separate thread for it to avoid confusion.

devil-80 wrote: »

Ok so to clear the things. New coil cylinder was installed. New ballcock in cold water storage tank. Level on that tank is fine. Only issue is with the smaller tank beside it with hot water I think for central heating. So water there rising everyone when I turn on heating and then is overload thru outside pipe. I don't know how to balance coil cylinder if that's the issue.

What you need to do is to is this.
Turn off the central heating for a few hours, or overnight.
Empty at least half of the water out of the small water tank and measure the level of water left in the tank.
Use something to keep the ballcock on this tank closed and make sure it is not dripping.
After a few hours or the next morning, check the level of water in the tank BEFORE turning on the heating or using the immersion to heat the water.
If the water is higher, or has reached the overflow, you have water entering the system either through the hot water cylinder coil or elsewhere.

Edit:
JohnG just in ahead of me with the same suggestion

devil-80 wrote: »

I thought it is the same thing alpha1 and alpha 1l mine is 1L. How to empty that small tank ?

The two Pumps are completely different animals, will advise back later.

If you have access to the tank just get a jug and keep removing water into a dish/bucket until the ball cock just starts making up/stopping and take tank measurements. or measure the amount of water removed.
If no access to the tank you could drain some water from a rad vent, easy enough if you have them on the ends of the rads, get someone to listen while doing so until the ball cock just starts opening and try and get a rough idea of how much you have drained.

Edit: Before you do any draining etc I would change the pump mode of operation.

Just to avoid any confusion confirm that your pump/control face plate is as page 1 of attachment.

Your present setting of 2 is IMO more than likely causing pump back to the F&E tank as it is still starts at 6.5M head.
As I said in post #9 even speed 1 will pump up to 20 LPM @ 4.4M head which might still possibly/probably cause pump back.

In view of this I would suggest changing to UFH mode FIRST,(page 10 of attachment), from what I can determine, this is a constant pressure of 3.0M which shouldn't cause pump back. (also check all rads hot with HW coil in operation as well)
You could then try radiator mode which I think starts at 3.6M and modulates down, I think this mode may be a bit "weak" but no harm in trying it.
Finally I would try fixed speed 1 and see if any pump back.

You can then decide which of the modes to finally "keep".
radiator mode consumes the least power followed by UFH power & finally speed 1.

You might let us know how you get on. Thanks.

devil-80 wrote: »

I thought it is the same thing alpha1 and alpha 1l mine is 1L. How to empty that small tank ? Is wide 40x30x30cm. I can open the lid and remove excess of water with jug - done now.

Also before I change the pump speed there was a water flow from the pipe on the top of this small storage tank.

After few minutes when heating is on I could hear something like water heating healing or something is that pipe extension because of heat or could be something else.

The tank holds 36 litres of water so even if its 1/2 full normally there should be plenty of room for the 3 litres or so expansion required when system hot.
The difference in the cold/hot level should only be a inch or so.

What pump mode are you on now and has it stopped the pump back or water rising in the tank??.

devil-80 wrote: »

Hi Guys. Thanks for help
I was out last night so couldn't check anything. I'm working today but will try to check this tomorrow. I set pump mode at 1 but I think there was still a little bit of overflow not much. In small tank yesterday was good below that overflow hole will check later how it looks -when I'll be back from work. Thanks again.

What's probably happening is that air is being drawn in through the vent, its then expanding in the hot system and displacing water up through the feed pipe and increasing the level to the overflow point, this will very quickly corrode your system.
It looks very much like that speed 1 is still too powerful so you could/should try the UFH mode next IMO.

K.Flyer wrote: »

If that is the case then it may indicate the plumbing is wrong (cylinder replaced?), or more likely that the replacement pump has been put in the wrong way around.
Even with that in mind, if my understanding of the o.p.'s description is correct, that the tank is always full to the overflow.
If the water level is being increased due to the positive pressure from the pump, enough to reach the overflow, surely when the pump is turned off then the water should level back down and the tank shoud only refill as far as the ballcock allows and no further.
If he ties up the Ballcock and runs the heating, then if your theory is correct that the pump is displacing the water, the level in the tank should noticeably drop down once the heating is turned off.

My theory is that air is displacing the water, when the system cools down if that is the case then the level will still remain high unless the air is released by venting rads etc?.
The pump orientation should certainly be confirmed as being correct or not, if everything is "as was" then I think that speed setting 1 is still on the high side as the pump will still give up to 20 LPM @ 4.4M which is greater than a lot of the older circ pumps at speed 3 with traditional fixed speed settings, that's why I suggested originally to try UFH (or Rad) mode first.

That aside, the Alpha 1 L has strange fixed speed settings, speed 1 and 2 are both 6.4M then that head doesn't start to drop on speed 2 until the flow rate is > 11 LPM and as stated above speed 1 is very powerful as well. It also, if I am interpreting the manual correctly, has only one CP (constant pressure) setting at 3.0M & one PP (proportional pressure) setting of 3.5M.

One could expect pitching if you had boiler flow then vent then cold feed then pump but some systems were done boiler flow then vent but the cold feed was teed in before the boiler so in this case the water could tend to pump up through the cold feed and pull air in through the vent. My own (47 yrs) system has a combined feed&vent with the pump on the boiler return with never a problem.

K.Flyer wrote: »

...then he should be experiencing "pitching" through the expansion pipe if the pump is too strong. But there has been no mention of that symptom from him.

Is that not what he has been talking about since the beginning?

wiz569 wrote: »

Is that not what he has been talking about since the beginning?

If that,s the vent pipe then there should be no gate valve in the hot feed to the cylinder as the vent continues on up from there and should be completely unrestricted.

John.G wrote: »

If that,s the vent pipe then there should be no gate valve in the hot feed to the cylinder as the vent continues on up from there and should be completely unrestricted.

Spotted that as well, I wonder what else might be wrong with the pipework :rolleyes:

devil-80 wrote: »

I'll check tomorrow how pump is fitted. So far I notice that water goes to tank small tank thru this pipe with yellow arrow. Water is warm in that small attic tank. Also I could hear some kind of banging from time not sure from where.
I have it same problem before pump was replaced that noise and water overflow so plumber told me that's my old pump not going strong enough.

Also tomorrow, see whether the pump is installed on the return to the boiler with arrow pointing into the boiler OR is installed on the flow from the boiler with the arrow pointing away from the boiler. Also if you can see where the cold feed is connected into the system.

John.G wrote: »

From post #11 "Hi. It's overflow pipe outside at the roof."

That happens because of the pitching I'm presuming?

devil-80 wrote: »

Will change it today also make picture how looks pump connection. When heating was off water didn't rise in small tank.
Arrow at pump is pointing down.

Pump is correct, on the boiler flow, pumping away from it.

You might note the pump power on speed 1 before you change to UFH mode and then note it again in this mode.

If pitching ceases and if the rise in the tank level doesn't reach the overflow then you can probably live with it even though not ideal, you might also note if the level rises as soon as the pump starts up of if it rises after the system heats up.
Also see where cold feed tees into the system.