Immersion heater temperature problems

[stardanny]

He also said that sometimes the ‘overfill’ trips so I’d need to bail water out of the brass expansion chamber in the top.

I find that the overfill switch is tripped during the night and I have to bail the water out of the expansion chamber before I can take a shower. Even then the same problem applies.

I haven't seen that cylinder before, interesting.

There must be a reason why the overfill switch is tripped and you have to bail it out of expansion tank. The overfill switch, when tripped, also closed off the cold supply to coil for hot water. I reckon you have a pinhole leak thro coil so cold supply leak into heat store and raising water level up to where it's tripped the switch which stopped to cold water coming in by that shut off valve.

There a way if it is a pinhole, remove the flex pipe attached to valve with blue knob and hang it up and tie it. If the overfill tripped again, you got a pinhole leak.

Daniel.

 

[picasso]

Thats why I asked the op to disconnect the filling loop.

 

[RickyTheCat]

Thanks Picasso.

Ok so I've used it twice now - and while it seemed to run hotter the first time, the same problem occurs - the water gets cold quickly. What should I check/replace first? What's cheaper??!

 

[Agile]

I think that you may be over expecting what the unit can do.

The normal cylinder stores water at 60 C ready to use. So the whole cylinder full is available for use.

Yours stores it as 75 C and in practice you only have the heat available from 75 c to 50 C before the water out becomes cooler.

I have not read the instructions for yours but most store at 85 C.

Even so I see them as being the most useless units ever devised having no advantages and many disadvantages.

Tony

 

[RickyTheCat]

@Agile - According to the manual the temp of the store should be set to 75 degrees (as it now is), but the water coming out is limited to 51 degrees "to avoid scalding".

I'm more than happy to consider replacing it, however as I live in a flat I don't think I'm allowed to run an outflow. Do I have any other options?

 

[stardanny]

Yes, you have other options, you can run an overflow via a tundish and a small trap and connect to waste pipe for kitchen or bathroom.

Did the water level rise and tripped overnight with the flex disconnected?

Daniel

 

[RickyTheCat]

Ah yes, that makes sense. No, the overfill didn't trip - I guess if it did the coil might be leaking somewhere?

 

[picasso]

Tomorrow morning when the store has been heating overnight run the shower until you dont have to add cold water , then check the pipes going into the mixing valve, if the hot pipe is still very hot the mixing valve is gone and if the pipe is the same temp as the shower the store isint heating properly.

 

[RickyTheCat]

Genius! Will do, thanks

 

[RickyTheCat]

I forgot to check the mixing valve this morning.

However, if I did decide to swap the thermal store for a 'normal' immersion heater, can anyone tell me roughly how much replacing this might cost me? Parts and labour?

 

[picasso]

unvented cylinder supply and fit approx 2k + (dont forget a discharge pipe has to be routed to outside) service for what you have now (with possibly a new mixing valve/immersion heater stat) £350.

 

[Agile]

I expect many would supply and fit a 210 li unvented cylinder for more like £1400 or even less.

We could assume that the mains water supply is already adequate.

Tony

 

[RickyTheCat]

The loo is just the other side of the left hand wall in the photo...I expect any outflow pipe could just be fed into the waste trap there.

Is 210 litres a standard size? What sizes do they generally come in? Would it affect my water pressure (mains water pressure)?

 

[Agile]

Your current store uses mains water pressure so that's obviously adequate now so would be for a new unvented.

UVs usually in 110, 150, 210, ( 250 ) and 300 lts.

210 would be better for you.

But if your store was OK before then there is a fault which could be sorted out.

Tony

 

[picasso]

210 ltr unvented cylinders are about the £900 mark,would you really fit a cylinder in london for £500 ?