Hot water vented system, cylinders gets empty at top

[fareedattary]

Hi. I m new on this site. have a question, which is confusing me. there is a hot wate cylinder, in vented system, with tank in the loft. A number of plumbers are called in the property, they just change the emersion heater, but the problem is not resolved, the reason is that the emersion heater it self is fine, but somethng makes it to cut-out. I think its some air produced on the top of the cylinder, i mean the cylinder gets empty at top, which seems silly to me. what else could it be. And What will be the solution.

 

[JohnD]

have you got a shower pump?

What makes you think there is air in the cylinder?

How high is the cold water tank above the cylinder?

What temp is the water from the hot tap?

Is the cylinder also heated by a boiler?

What country are you in?

Why don't you just reset the cutout?

 

[fareedattary]

have you got a shower pump?

What makes you think there is air in the cylinder?

How high is the cold water tank above the cylinder?

What temp is the water from the hot tap?

Is the cylinder also heated by a boiler?

What country are you in?

Why don't you just reset the cutout?

1- There is no shower pump.
2- The upper bit of the emersion heater looks dry when i took it out of the cylinder.
3-The Cold water tank is about 7 feet high.
4- temp at hot water tap is not enough for washing puposes, even its cold for hand wash.
5- Cylinder does have a coil in it, but its not heated by boiler.
6- I m in UK.

 

[dextrous]

Is there a pipe that comes out from the top of the tank which feels hot?

 

[fareedattary]

Is there a pipe that comes out from the top of the tank which feels hot?

the hot wate outlet, obviously comes from the top of the cylinder. In tank, there is one pipe for expansion and air vent. i didnt check if it was hot or not.

 

[dextrous]

The air vent is usually the pipe at the top of the tank which is also where the hot water is drawn from. If it is there, then it is impossible for the top of the tank to dry out.

 

[fareedattary]

The air vent is usually the pipe at the top of the tank which is also where the hot water is drawn from. If it is there, then it is impossible for the top of the tank to dry out.

First of all, thank you very much for all your help. I am very grateful to you.
The vent pipe is there, as you said, from the hot water outlet to the tank. So the cylinder should not get empty at top. Unfortunately, I can not understand why the emersion cuts out, and why the top of emersion is dry.

 

[Slugbabydotcom]

If someone has bodged a connection to the top of the cylinder it might be possible that they have created a 'dip pipe' which could be creating an air space at the top of the tank.
Post a pic and we can check it out for you
Yes I know its a million to one shot but so was the 25m of alkathene stuffed under floorboards with 8 kinks in it that I mentioned in an earlier post.

 

[ManxPlumber]

1. your immersion cuts off because it has a thermostat, you can change the temp on the head but isolate it from the electric supply 1st
2. IF the

cylinder gets empty at top

you wouldn't get any water out of the hot taps
3. IF the cylinder isn't filling fully, the feed from the CWST is either partially blocked or the gate valve isn't open

 

[fareedattary]

1. your immersion cuts off because it has a thermostat, you can change the temp on the head but isolate it from the electric supply 1st
2. IF the

cylinder gets empty at top

you wouldn't get any water out of the hot taps
3. IF the cylinder isn't filling fully, the feed from the CWST is either partially blocked or the gate valve isn't open

the temperature set at the termostat is 65 degree. but the hot wate temp is not more than 20 degrees.

 

[ManxPlumber]

20°C is cold main temp, so ~ sounds like it's either not connected to the electric supply, or the fused spur isn't switched on, or try checking the consumer unit, maybe the Plumber isolated the old one but forgot to turn the power back on!