Indirect Cylinder Hot Water Help

Somebody

FWIW, my view/experience and what works for me :-  the immersion heater(s) (I have 2 - top and bottom of an unvented tank) is backup for heating the HW in case you can't heat via the gas boiler.  I think I have only ever switch on the electric heater during 3 days in 18 years due to boiler issues. 

With regards to heating the HW tank via the boiler, I'm into home automation, and have Evohome with a morning and longer evening HW heating schedule, set point of 55ºC and offset of 9ºC which means that the HW won't be heated unless the HW temperature is below 46ºC.  Normally the evening heat schedule is enough for the HW to last a whole day so no morning heat schedule needed.  On the occasions that the HW falls below 30ºC during the day I have an automation that turns on the HW heating at 5pm for half an hour so we can have HW for dinner preparation etc.   

This is the HW temp chart over the past 2 days with a rare morning heat this morning: 

bob2302

Bendo said:

If by instant you mean after letting the tap run for a while and by hot, you mean lukewarm.

Mine isn't lukewarm.

JohnSwift10

Bendo said:

If by instant you mean after letting the tap run for a while and by hot, you mean lukewarm.

Yes but mine is hot enough that I can't keep my hands under the tap for very long without some discomfort.

You do know that you can adjust the temperature of the hot water coming out the tap, don't you?

Scot_39

matelodave said:

Its also a good idea to reduce your tank temp down  to around 50 degrees - a hotter tank loses more heat and you end up diluting your hot water with cold to make it usable.

50C might be a bit low for a vented (old style gravity fed from cold loft tank in particular) - if at all worried about legionella risk etc.

But landlords have to have afaik all standard sized tanks set to 60C min - as businesses still do - and explicitly afaik inform their tennants not to lower. 

If in that scenario - and worried about scalding fit a TMV mixer just before HW taps - in a modern home you may already have 1 on your bath (and according to Scottish gov website bidet if have one).

RedFraggle

I had this set up. Make sure the boiler is set to high, that's what Gledhill recommend for the system to operate efficiently. The boiler heats hot water that surrounds a coil in the bit of the Gledhill that looks like a water tank. When the hot tap turns on the water flows through that coil and is heated to give you DHW. There's a reservoir in the top of the Gledhill that must have water in it. It should have a lid to limit evaporation but they often get lost. A dining plate the right way up is a good solution as it makes the water condense back in.
If you're based anywhere Essex/London I think I still have the details for the chap that used to deal with mine.