Using an Immersion heater to support a rubbish boiler?

Caporegime
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8 Mar 2007
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37,146
Location
Surrey
In the house I've just moved to the boiler is rubbish. It looks like its from 1960 and is isn't a combi boiler. Even after the hot water has been on for 3 hours there's still only just enough for 2 showers at a push. If we have people stay it's a nightmare. I don't know if its just the boiler being rubbish or the hot water tank is too small or rubbish.

There's an immersion heater in the tank, but as they are £lol expensive to run I've not turned it on. But I think I'm going to have to. What's the best way to combine a boiler and immersion heater? I was thinking of having the boiler on for a few hours to fill the tank and then have the immersiom heater kick in when the boiler goes off to keep the water hot and serve any extra needs we have. Id only run it for a few hours.

Any suggestions?
 
Try turning the water temp down on tank to minimise electricity use/ heat loss. Then use Boiler to boost ? I lived in a flat with electric hot water tank and bills weren't too bad

What electricity rate are you on ?

Alternately fit an electric shower.
 
Its a rented place so I can't fit a new shower. If it were mine I'd be redoing all the plumbing and boiler.

No idea on rates.
 
The heating is fine. Takes a little while to heat up but the radiators get plenty hot. There's a few I need to bleed but I haven't got round to it yet.

There's only one set of timer controls on the boiler that does both, so I assume hot water and heating are on the same system?
 
Do you hear the 3 port valve opening/closing if you adjust the thermostat on the hot water tank?

50 year old ones could be gummed up or the motor burned out.
 
Does the thermostat on the hot water tank work without the immersion heater on? I've not touched it as the immersion is off and I assumed they were connected?
 
Sure you are not missing a knob you have to turn up?

I have the same set up, but the gas boiler has a temp dial...which is near the immersion heater.

The immersion heater has another temp dial for when using electric to heat the water.


It is kinda confusing with both boilers using the same tank (the immersion heater) and double sets of dials all in the same place.

Yes, the water will be heated by the gas if the imersion is off, and if the central heating is off.

HTH, haha!
 
Do you hear the 3 port valve opening/closing if you adjust the thermostat on the hot water tank?

50 year old ones could be gummed up or the motor burned out.

It's probably a 2 way. With hot water always being on no matter if heatig is or isn't. You then you chose whether to then do heating and hot water or hot water only. However if he's turning them both on together then the heat loss to radiators may be limiting the hot water temps

Have you tried just hot water to see what that's like? If it's a old heating controller you may not have the option ?
 
OK.

The timer controls by the boiler have buttons for hot water and heating to turn to on, off and timed. However there is only one set of timings you can make meaning both are timed the same if set to timed (this differs to previous houses where I've had seperate timings for water and heating). Both are on timed at the moment.

The boiler itself has a thermostat on the front that goes from 1 to 6. It's set to 6.

The heating control on the wall in the hall is set to 21 and seems to be working fine.

The immersion heater into the hot water tank upstairs has its own timer and control box, but is currently switched off at the mains so isn't on at all.

BUT... there is also another thermostat in the hot water cupboard I hadn't noticed before. Its on (little digital readout) so can't be connected to the immersion control box. Its currently set to about half way. It currently shows 24c. If I move the thermostat it shows that the target temp should range between 40c and 65c, before then going back to show the current temp of 24c I pressume?

Is this newly discovered thermostat my issue? Is it going to be connected to the boiler downstairs? Shall I whack it on full and see if it makes a difference?
 
That's probably your tank water temp. Wind it up to max for now

Have you used up all the hot water and it's been off as it obviously should be above 40c

The boiler control is outlet temperature so only effects the heat input to the hot water coil in the tank. Once the tank is up to temp then the other stat cuts demand to boiler. If it's a small tank then higher water temps mean you will get 'more hot water' as you will need less hot water for that se shower outlet temp.

Do you know the rating of the boiler. Its going to be working hard in this weather and probably isn't that powerful Plus it sounds like it's having to try and warm the house at the same time
 
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