iBoost causing tank overflow?

JimLad

Hi Everyone!

At the weekend we had a very sunny day so the iboost was heating away all day 16kw in total.

Towards the end of the day i noticed a trickling sound coming from the airing cupboard. When i opened it up it was the overflow pipe that comes off the hot water cylinder. It makes the noise because there is a plastic section (i guess designed to make a noise?).

My knowledge of hot water systems is somewhat limited, but i wonder if it could have been the iboost causing this? Does hot water expand perhaps? I have the immersion thermostat set at 3 (it goes up to 4). Maybe it needs to be lower?

James

System

Do you have a vented or unvented hot water cylinder? If you can see the water running into a tunidish, then it is unvented. In this case, you need to follow the manufacturer's instructions to re-charge the cylinder. usually this is achieved by turning off the cold water supply; opening a hot water tap at the lowest point you can and then holding open the valve above the tunidish. You will then have about 20 minutes of gurgling and water dripping into the tunidish. When this stops get someone to confirm that hot water has stopped running from the downstairs hot tap. Release the valve above the tunidish and turn on the cold water supply. Leave the hot tap open until all the air has been expelled. Close the tap and check that water has stopped dripping into the tunidish.

If this doesn't solve the problem, then call a plumber who is qualified to work on unvented hot water systems.

If your hot water cylinder is vented, then ignore all of the above.

Dave_Fowler

JimLad wrote: »

Hi Everyone!

At the weekend we had a very sunny day so the iboost was heating away all day 16kw in total.

Towards the end of the day i noticed a trickling sound coming from the airing cupboard. When i opened it up it was the overflow pipe that comes off the hot water cylinder. It makes the noise because there is a plastic section (i guess designed to make a noise?).

My knowledge of hot water systems is somewhat limited, but i wonder if it could have been the iboost causing this? Does hot water expand perhaps? I have the immersion thermostat set at 3 (it goes up to 4). Maybe it needs to be lower?

James

Hi James,

The water will expand when it heats and that could account for the overflow. If it is due solely to the heating effect, the overflow should stop as soon as the water has heated to its maximum when the expansion will also be maximum. If this is the case it sounds as if the ball-valve setting is such that the tank is already completely full before you start to heat the water.

A simple solution would be to set the valve screw adjustment so that the level in the tank is a little lower so that there is no overflow when the water is heated.

Dave F

JimLad

Hengus wrote: »

Do you have a vented or unvented hot water cylinder?

Unvented (I think....Its fed by the mains water and has pressure cylinders?)

System

JimLad wrote: »

Unvented (I think....Its fed by the mains water and has pressure cylinders?)

Google unvented cylinder. If it is vented, then hot water expansion may run back into the header tank in the loft.

JimLad

Hengus wrote: »

Google unvented cylinder. If it is vented, then hot water expansion may run back into the header tank in the loft.

Its definitely unvented

System

JimLad wrote: »

Its definitely unvented

I assume that there is a thermal cut out on your immersion heater? Mine is set at 60C. In my experience hot water rarely flows out of the cylinder unless there is a problem of some sort. How hot is your hot water actually getting?

pinnks

Are you sure your immersion heater thermostat is working and you are not bringing the water to boiling point?


I have had an Immersun which I think does the same thing as the iboost and the most I have ever fed through mine was today as it happens at 6kWh - and that included powering a radiator once the water had reached temp.


I think the most I have ever put into the hot water alone is less than 3kWh. That said we are only 2 adults and shower not bath people, so it will also depend to some degree on personal circumstances.

JimLad

Hengus wrote: »

I assume that there is a thermal cut out on your immersion heater? Mine is set at 60C. In my experience hot water rarely flows out of the cylinder unless there is a problem of some sort. How hot is your hot water actually getting?

pinnks wrote: »

Are you sure your immersion heater thermostat is working and you are not bringing the water to boiling point?

Very interesting point, maybe the thermostat on the immersion is broken.... Its hard to know as im out during the day. Yesterday was pretty sunny and only put in 5kw after i had adjusted it down a bit.

Maybe to test it I will temporarily put the dial down to zero and see if it still puts loads in?

evomatt

If your immersion is heating the whole tank (ie from the bottom of the tank) you could easily put 16kwh into it. Most are at the top of the tank so will only put about 4kwh into it (enough for a hot 10 min shower)

Sterlingtimes

evomatt wrote: »

If your immersion is heating the whole tank (ie from the bottom of the tank) you could easily put 16kwh into it. Most are at the top of the tank so will only put about 4kwh into it (enough for a hot 10 min shower)

Interesting posting. So far I have not exceeded 4 kWh in a day so I am pretty sure that you are right. Disappointing.