Water too hot - Help understanding new boiler system

Snaaap

Hi, I’ve just moved into a new rented house. The water is too hot and the system is confusing to me. Previously lived in combi boiler houses which I found fairly simple.

This seems to be a conventional boiler, Ideal Classic RS30. This is downstairs. It has a dial, 0-6, and that’s about it.

In the hallway is a control which has seperate CH and HW setting sliders: Off, Timed, Once, On. You can program a timer. There is no thermostat here.

Radiators have thermostatic valves.

Upstairs in the bathroom there is an immersion heater. This seems to have a power switch, a thermostat and a timer (one with a clock dial and pins to insert for on/off times).

The immersion heater was on 60 which I understand to be a good temp, but I turned it down to 50 to test it. I used up all the hot water and then left it a couple of hours. The water is still very hot- enough to hurt just passing your finger through, and steam comes off when running.

So my impression is the thermostat is broken, HOWEVER, there are a couple of things im confused about which may be related.

Firstly, we’re running the CH all day from 6 to 9. We use the radiator valve to control room temperature but as there seems to be no general one for the boiler, does this mean the boiler is heating water constantly? From diagrams I’ve looked at for conventional boiler systems, the water returning from radiators is considered ‘cool’ and feeds into the immersion heater. But if all radiator valves are shut due to reaching adequate roomtemperature BUT boiler is still passing hot water through them, doesn’t this leave the potential for very hot water to return from radiators and enter the immersion heater where hot water comes from?

So I tried turning the boiler down to 1 but it still seems hot. So maybe it is the immersion heater thermostat that’s broken- but I’m still intrigued by how it all works.

The other thing is.. why is there a control for HW downstairs as well as by the immersion heater. Does the hallway control turn off the immersion heater?

Why is there a timer in the hallway as well as the immersion heater?

Snaaap

Btw the water seems to be at least 70 - apparently the max temp shown on the floating duck digital thermometer we have for checking the babies!!!8217; bath temp.

Browntoa

Is it a standard immersion or is it a megaflo system that uses the boiler to heat the water ?

If so then turn the electric off to it , they have a standard immersion for emergency as well which is not needed if the boilers doing the heating

Snaaap

Think it!!!8217;s standard. Labels on it include:
Fortic Combination Unit
Herculag

getmore4less

Immersion heaters normally have their own thermostats under a cover.

Any indirect heating will have a its own stat attached to the cylinder. .

some pics might help understand what you have.

First thing is work out what's heating the water and which stat is controlling it.

if you turned the indirect stat down but the immersions are on....

Snaaap

Ah I think I!!!8217;ve realised a mistake in my thinking. I thought !!!8216;immersion heater!!!8217; meant the tank. But you can have a tank without an immersion heater right? And an immersion heater is just an additional/back up thing for the tank that runs on electricity, separately to the boiler?

In which case my next experiment is to have the boiler HW on but the immersion heater on. Thanks

Snaaap

Edit doesn!!!8217;t seem to work, sorry. Last sentence above, I meant immersion heater *off

Browntoa

This is a megaflo

https://www.heatraesadia.com/products/cylinders-and-hot-water/unvented-cylinders/megaflo-eco

They also function as immersion Heater if required

pramsay13

Your boiler controls CH is for central heating and HW for hot water. Off means they are off, Timed means they run on a timer (there will probably be a few on off times during the day), Once means it comes on at the first on but then stays on until the last off rather than switching on and off during the day, and On means they are always on.
The 1 to 6 on the boiler will be temperature control, 6 being the hottest. I'd say around 4 should be fine for baths / dishes etc.
Assuming it is on central heating it will be heating the water and sending it around the radiators then to a storage tank (I think this is what you are calling an immersion heater).
You can control the heat at each radiator to control how much water gets into each radiator to heat the room.
Once the hot water has reached the storage tank you can use it for dishes / baths etc. until it runs out and water goes cold.
If the boiler is on hot water setting the hot water bypasses radiators and goes straight to storage tank.
The storage tank will also have an immersion heater which is a separate electric system and is used to heat the water in the tank after it has gone cold and you can't wait the half hour / hour until the boiler water heats up the water enough to fill the tank.
This is an expensive way of heating the water so use it sparingly.
It sounds like you have had this on all the time so your water is always very hot, but be prepared for a large electric bill.
There is usually a thermostat in the hallway. You set it to the temperate you want the hallway to be (e.g. 21 degrees) and if it reaches that temperature the boiler will switch off (even if it is still on by timer etc.)
It sounds like you might not have one of these.
Hope that all makes sense.

southcoastrgi

Set the hw times on the programmer in the hall, turn off the electric to the timer next to the cylinder set the boiler on 4

Snaaap

Thanks all, I think I get it now. Hot water seems ok with immersion heater off for an hour and boiler set to 3 (will try 4 later based on above suggestion).

I think the immersion heater thermostat is definitely broken given I was getting at least 70c+ with it on despite being set to 50c. However, I won!!!8217;t worry about that too much now. Sounds like the immersion heater is an unnecessary most of the time.

Going to check the meter in a bit- gulp! Thankfully we!!!8217;ve only been here a week.

Was the broken immersion heater potentially keeping it at near boiling? Wow...