Water Slow to Heat and Poor Pressure - Two Switches in Immersion Heater Cupboard

[ChrisP99]

Hi,

I have absolutely no knowledge in this area so apologies if this is a silly question!

I have recently moved into a flat where the hot water is supplied via an immersion heater in a hot water tank. The tank has two thermostats, one at the top and one at the bottom. The hot water takes a good while to heat up when it's turned on (about 45 seconds to a minute), and the pressure is really, really bad. I'm unsure if that's because I'm not controlling the heating right, or if there is a fault.

There are two switches in the cupboard. The switch on the right has a wire which goes to a thermostat at the bottom of the hot water tank, and the switch on the left is seemingly connected to nothing. There's also a large tank on top of the hot water tank, and I also have no idea what that does (Like I said, I have no knowledge in this area ).

At the minute, I have the switch on the right turned on, and the switch on the left turned off.

We have an Economy 7 tariff for our electricity, and I'm aware that this means we get cheaper electricity at night. Am I right in assuming that the wire going into the thermostat at the bottom will be for cheap electricity, and would anyone have any idea what the purpose of the other switch is? I know that there are switches that can work to provide instant hot water when needed and this is charged at the peak tariff, but there's nothing on the switch to indicate what it does, and it's not connected to the other thermostat (I don't know if that actually matters).

There is also a switch in the kitchen with a label that says "Water Heater" with a light on it. I have no idea what this does either in relation to the other two switches, and when the two switches in the cupboard are turned off, the light stays on.

I'm aware that I probably need to get someone to physically take a look, but I am hoping that somebody here has an idea of what they do before I do that. The property is rented and both the tanks look absolutely ancient, so if I can make an argument for it to be replaced, it would be useful because the lack of pressure and time it takes for hot water is starting to become annoying.

Thanks for your help in advance!

 

[terryplumb]

Your water isn't instantaneous,it is heated for a period ,hours not minutes initially, and stored in the cylinder.
Your tank above the hot water cylinder feeds it ,and it's gravity fed that's why pressure is pants !!
Pictures of the full cylinder would be useful.

 

[ChrisP99]

Ahh I see. Okay, I suppose that can’t be helped then which is a shame

Here’s a pictures of the full tank. The top thermostat has nothing connected to it so I’m unsure of what the second switch actually does.

 

[terryplumb]

The upper immersion heater has no electrical connection ,so it won't do anything at all.
Its possible that one of the two switches next to each other may be an unused supply for the upper immersion ,but it's anyone's guess.
The remote switch with red light is likely to be connected to the lower immersions switch ,and in a more convenient place (usually in the kitchen) . So both would need to be turned on for the immersion to heat up. The one next to the cylinder left on permanently ,and the one with the red light used when water needs to be heated. If they are connected to a cheaper rate tariff ,all the better.

 

[JohnD]

What do you mean by "slow?"

A 3kW immersion heater takes cold water to hot at the rate of about 1 litre per minute. Because convection takes the hot water to the top of the cylinder, each element only heats water at or above its own level. Your upper element will heat a small amount of water reasonably quickly. Sometimes called the "sink" element.

The lower element heats a larger amount of water more slowly. Sometimes called the "bath" element.

It is common to have the lower element permanently switched on, provided it is fed from a timed, cheap-rate circuit that will fill the cylinder with hot water at about half-price. The upper element is only turned on if you run out of hot water during the day.

Your cylinder looks unusually small. What are its dimensions? Are you in a one-bedroom flat or retirement home? Is it rented?

I presume you have no gas boiler, which is a much cheaper source of energy.

Your cylinder is yellow, and the pipes are uninsulated. This would be around 30 years old, and not to current insulation standards. You can improve this and save money. Start with pipe lagging, you can cut it to fit with a bread knife. Your pipes are probably 22mm (banana) diameter and 15mm (finger) but check that before buying. They just might be 28mm as they are so old. The thicker grade is better, if it will fit. You can also add a red cylinder jacket, but they are rarely sold now as modern cylinders are factory insulated.

Search Lagging | Wickes.co.uk

Search results for Lagging on Wickes.co.uk

www.wickes.co.uk

The felt or hessian types are nowhere near as good as the stiff foam.


EDIT
I see the label says the cylinder is 900mm x 600mm, which is a reasonable size and adequate for a decent bath.

It will take roughly two hours to fully heat.

 

[CBW]

The top thermostat has nothing connected to it so I’m unsure of what the second switch actually does.

Nothing by the looks of it, twin immersions, and only one wired up. Neon switch could be additional to the immersion switches, or control a programmer.

 

[boringoldcodger]

The hot water takes a good while to heat up when it's turned on (about 45 seconds to a minute)

Do you mean that when you turn on a hot tap then it takes (best part of) a minute for hot water to appear?

 

[JohnD]

Run it into a bucket, time it, calculate how many litres of hot water per minute the hot tap delivers, tell us.

I expect the hot bath tap will be quicker.

What is the distance between the cylinder and the hot taps?

Lagging the pipes will make them cool down slower.

 

[fixitflav]

Hi,

I have absolutely no knowledge in this area so apologies if this is a silly question!

I have recently moved into a flat where the hot water is supplied via an immersion heater in a hot water tank. The tank has two thermostats, one at the top and one at the bottom. The hot water takes a good while to heat up when it's turned on (about 45 seconds to a minute), and the pressure is really, really bad. I'm unsure if that's because I'm not controlling the heating right, or if there is a fault.

There are two switches in the cupboard. The switch on the right has a wire which goes to a thermostat at the bottom of the hot water tank, and the switch on the left is seemingly connected to nothing. There's also a large tank on top of the hot water tank, and I also have no idea what that does (Like I said, I have no knowledge in this area ).

At the minute, I have the switch on the right turned on, and the switch on the left turned off.

View attachment 309626

View attachment 309623
View attachment 309625

We have an Economy 7 tariff for our electricity, and I'm aware that this means we get cheaper electricity at night. Am I right in assuming that the wire going into the thermostat at the bottom will be for cheap electricity, and would anyone have any idea what the purpose of the other switch is? I know that there are switches that can work to provide instant hot water when needed and this is charged at the peak tariff, but there's nothing on the switch to indicate what it does, and it's not connected to the other thermostat (I don't know if that actually matters).

There is also a switch in the kitchen with a label that says "Water Heater" with a light on it. I have no idea what this does either in relation to the other two switches, and when the two switches in the cupboard are turned off, the light stays on.

View attachment 309624

I'm aware that I probably need to get someone to physically take a look, but I am hoping that somebody here has an idea of what they do before I do that. The property is rented and both the tanks look absolutely ancient, so if I can make an argument for it to be replaced, it would be useful because the lack of pressure and time it takes for hot water is starting to become annoying.

Thanks for your help in advance!

As others have said, the top immersion is not connected. If you don't use much hot water it might be an idea to connect it and use that most of the time. You can check the resistance with a multimeter to see if it's in working order. You or your landlord need to decide how to connect them - via off-peak switch or direct.

 

[ChrisP99]

Wow this is a great forum, everyone here is so helpful!

What is the distance between the cylinder and the hot taps?

The bathroom is directly next to the cylinder and then the kitchen tap is directly next to the bathroom - Pretty much all in a straight line. I haven't actually tried using the bath, but I ran the tap and it's just as bad as the rest of the flat, even though it's the closest thing to the cylinder. Like someone else said it's gravity-fed so I am going to assume the only solution is to get a pump installed (This is from my very limited Googling capabilities!). The shower is a Miro Go electric shower and therefore slightly better.

Run it into a bucket, time it, calculate how many litres of hot water per minute the hot tap delivers, tell us.

I don't actually have a bucket to measure how poor the pressure is at the minute, but what is also annoying is because of the lack of pressure, the hot water is scalding hot (after quite some time) when turned on with barely any pressure, and if you try to turn the cold tap on to offset it and also get a bit more pressure, the tap is just freezing cold, which is a nightmare for cleaning dishes.

As others have said, the top immersion is not connected. If you don't use much hot water it might be an idea to connect it and use that most of the time.

That's great information, I will contact the management agent with this information. They've been very helpful with other issues so far and the cylinder is 30 years old going off other experts in the thread so I will ask them to install lagging and potentially connect the top immersion.

Does it matter immersion is direct and which is off-peak, is one more efficient than the other? At the minute the bottom is off-peak but it could be switched obviously.

Neon switch could be additional to the immersion switches, or control a programmer.

I need to look at getting an actual programmer installed actually because there isn't one, and to be honest I have no idea what times the immersion is set to go on and off at... It does come on at night so I assume it's okay but it would be nice to know.

 

[terryplumb]

The thermostat is within the immersion heater ,and accessible under the black round cap ( which shouldn't be removed before turning electric supply off)
If your hot water temperature is too hot ,the thermostat needs attention / setting lower/ or replacing.
If you want hot water to be heated in the cylinder at certain times ,you would need a timer installed.
As the lower immersion heats all water above it ,that should be connected to the lower tariff ,unless you don't use much hot water ,then the upper element would probably be better utilised.

 

[JohnD]

The immersion heaters have an integral thermostat, which can easily be adjusted or replaced.

TURN OFF THE POWER and you can then undo the screw retaining the cup-like plastic cap. Take a photo. You should be able to adjust it with ease.

With age, the thermostat can fail and the water get very hot, which is dangerous and wastes electricity. If you have a thermometer, take the maximum temperature of the water. If it has failed, the landlord should get a plumber to replace with new.

Edit
Too slow!

 

[ChrisP99]

That's great advice thank you so much both!

I will turn off the power and have a look. I have a Mira Go electric shower. The water is hot with pretty poor pressure when it is set to the cold position. When I set it to the hotter position it is underbearable and the pressure is awful.

I only had a medical thermoeter and it just said "Hi" when I ran it under the sink but I believe the maximum temperature of that is only 42c - The water is obviously much hotter than that.

 

[terryplumb]

Your electric shower issue is totally Seperate from the hot water temperature from any taps.
Your shower takes in only cold water ,and heats it as it runs through the shower.
If you turn the lower dial fully anticlockwise on the shower ,the temperature should drop significantly and the flow of water increase substantially. Does it ??

 

[ChrisP99]

Ahh I see, as you can see I am showing my lack of knowledge well here!

When the dial on the shower is fully anti-clockwise, there is a very good flow of water. However, I would describe the water as lukewarm, it definitely isn't cold.

This is what position the dial is in when I usually take a shower - I like hot showers and it's quite hot even when it's here, with an "ok" amount of pressure. It's not amazing, but good enough.

This suggests to me that the shower is faulty as well... something I never even considered. I have no idea what the Low and Eco switches mean because there's no manual either. Unless it's meant to be this hot when it's set to High?