immersion heater hot water problem

keystone

Canucklehead wrote: »

Hi

That would be a thermostat problem then.
E7 isn't responsible for that.

Set stat to 60 degrees .If it overheats ( doesn't switch off) replace the stat.
GSR.

Thanks but thats not what I meant - sorry if I misled. According to the OP in the Utility Board his E7 doesn't always switch off when it should so we could have the situation where the stat is a bit too high but is functioning correctly. If the E7 doesn't switch off then as the temp falls the stat will kick the IM on again and off again and on again.

Turning the stat down would test that but if it then overheats yes - replace the stat.

Cheers

keystone

birkee wrote: »

Cold water tank sat on top of the hot water tank with a direct feed down. little head pressure compared to loft tank supply. Use where there is no space for a loft tank usually.

Thank you.

What else d'yu want me to say?

Well in post number 8 you said that it was not an air problem but the OP needed to have 6 feet head 'twixt tank and cylinder. So my enquiry was "how does a fortic work then" because that doesn't have 6 feet. Anyway - it really doesn't matter now - forget it.

Cheers

sat56

Thanks for your help.

Forcing mains up the pipe didnt work, still got the problem.

The e7 issue with my storage heaters is unrelated as my immersion heater is on a separate timer and is set to the minimun time of 3 hours.

I have created a drawing the best i can.

birkee

sat56 wrote: »

Thanks for your help.

Forcing mains up the pipe didnt work, still got the problem.

The e7 issue with my storage heaters is unrelated as my immersion heater is on a separate timer and is set to the minimun time of 3 hours.

I have created a drawing the best i can.

Like this?

birkee

DVardysShadow wrote: »

Suppose the pump is pumping to a full bore open pipe, discharging to free air. The outlet pressure is atmospheric pressure, by definition. The pump flow characteristic will dictate the pressure rise across the pump in the direction of flow. As the outlet is at atmospheric pressure, the inlet will be below atmospheric pressure by the pressure rise across the pump. Therefore the inlet of the pump will be at a partial vacuum pressure.

Provided the water source can meet the flow rate, this does not turn into a void in the inlet. If a void does develop in the inlet, of course the pump will not shift water and the pressure rise across the pump will disappear.

All that is being said, with the term vacuum being loosely used, is that the inlet side of a pump can be at a partial vacuum pressure.

It's water flow that creates the vacuum, not the pump. As soon as the pump picks up air, because it's outrun the water supply into the H/W tank, the pump will cease to pump water.

keystone

sat56 wrote: »

The e7 issue with my storage heaters is unrelated as my immersion heater is on a separate timer and is set to the minimun time of 3 hours.

Oh sorry - misread it. Forget all that then.

I have created a drawing the best i can.

Thanks for tha. Assuming its roughly to scale the problem clearly lies with the vent pipe. Any air in the tank is being drawn straight down into supply pipework as suspected. It stands no chnce of getting out of the vent which should go straight up from the cylinder.

Get the guys back who moved it to reconfigure it properly. In the meantime if your cylinder stat is high (should be no more than 60 degs C anyway) I really would turn them down a bit as that may help to alleviate the problem pro tem.

Cheers

keystone

birkee wrote: »

Like this?

It doesn't matter - his problem is and always was air in his pipework.

Cheers

birkee

keystone wrote: »

It doesn't matter - his problem is and always was air in his pipework.

Cheers

Not because the H/W outlet rate is outrunning the H/W tank top up rate?
Air in the pipework is a symptom of the fault, not the fault.

keystone

birkee wrote: »

Not because the H/W outlet rate is outrunning the H/W tank top up rate? Air in the pipework is a symptom of the fault, not the fault.

I said air is his problem not the fault. The fault is the long horizontal run in the vent. The air in the tank is being pulled into the supply pipework as it has no chance of escaping up the vent. Once the air in the tank is cleared all taps run fine which indicates that its not being pulled down the vent. Its a pipework problem. Once the vent is fixed if the CWST still can't cope then the next step is to upsize the riser but fix the vent first.

Pumping the outlet of the tank per your suggestion will only exacerbate the problem.

Cheers

sat56

Thanks for the replies.

Just so i Know what i want then to do is this a betteer configuration.