Immersion Heater Overflowing - No clue

ssm90

Evening All,

Apologies if this is in the wrong area, please let me know if it is.

So turns out, my flat has decided to give me it's own version of a Christmas Gift- an overflowing immersion heater! I have no clue about plumbing or boilers so there may not even be anything wrong. I'd really appreciate it if you could help me with this.

Image in link below
https://ibb.co/mcSwghg

1- Valve for cold water - Open
2- Pressure reading at 3.5 Bar
3- Pressure reading at 3.5 Bar
4- Valve for hot water - Open
5- Water overflow going down to the white pipe and then out to drain

The overflow at 5 seems to be constant and the water is boiling hot as well.

Can someone please explain why this is happening? The conditions described above (with open valves) have always been open so not sure why this is happening- is this normal? I have no idea how this combi heater works in the first place, all the valves are open so I imagine there is some sort of ball lever level(??) to prevent the overflow- if this is the case why won't it stop overflowing?

Any help would be appreciated - including an idiots guide to a combi boiler.

Thanks!

adonis

It could be that the thermostat has failed, try turning the immersion heaters off.

FestiveJoy

ssm90 wrote: »

Evening All,

Apologies if this is in the wrong area, please let me know if it is.

So turns out, my flat has decided to give me it's own version of a Christmas Gift- an overflowing immersion heater! I have no clue about plumbing or boilers so there may not even be anything wrong. I'd really appreciate it if you could help me with this.

Image in link below
https://ibb.co/mcSwghg

1- Valve for cold water - Open
2- Pressure reading at 3.5 Bar
3- Pressure reading at 3.5 Bar
4- Valve for hot water - Open
5- Water overflow going down to the white pipe and then out to drain

The overflow at 5 seems to be constant and the water is boiling hot as well.

Can someone please explain why this is happening? The conditions described above (with open valves) have always been open so not sure why this is happening- is this normal? I have no idea how this combi heater works in the first place, all the valves are open so I imagine there is some sort of ball lever level(??) to prevent the overflow- if this is the case why won't it stop overflowing?

Any help would be appreciated - including an idiots guide to a combi boiler.

Thanks!

So you appear to have an unvented hot water cylinder, which you indicate is leaking water via the tundish

There are generally 5 causes of Tundish discharge in such a system
1. Insufficient charge in the thermal expansion vessel
2. Back pressure in the system
3. System overheating
4. A problem with the Temperature Pressure Relief Valve
5. A problem with the Inlet Control Set

But these systems are quite specialised, and you really need the help of someone who specialises in them to rectify any issues, and the average heating engineer usually is not, let alone a DIYer.

It could be overheating, caused by a faulty thermostat.
But looking at the seepage marks on top of the main cylinder/junction of the expansion vessel may indicate insufficient charge in that expansion vessel.

Or indeed, any of the other possibilities mentioned above.
Seek expert advice would be my recommendation


:xmastree::xmastree::xmastree::xmassign:

matelodave

As said above it's a pressurised system and it's probably over heating. Turn off your water heating elements to reduce the temperature and get a plumber in to check the system because one of the safety valves is releasing pressure and hot water.

Theres is no ball valve, the system pressure should be regulated to around 2.5 bar or less with the regulator (item 2)

The pressure gauge (item 3) tells you that the pressure is at 3.5 bar which is usually the pressure that the safety valve (the one with the red knob by the tank) will vent and the water will be cold as it's coming from the mains. 3.5 bar is higher than the working pressure of the pressure vessel (the tank on top of the cylinder) so it will need to be checked and possibly recharged or even replaced.

The second safety valve (the one with the black knob) is set to 10 bar and about 90 degrees and will vent hot water/steam if the tank pressure or temperature gets too high.

As the water is hot then it's probably a thermostat fault causing the tank to overheat and vent hot water - get it checked out immediately

Make sure that the plumber is certified to work on pressurisd systems. Ideally the system should be checked over regularly to make sure that the pressure & safety valves are operating correctly and that the pressure vessel is properly charged.

As said above the trail of rusty water down the side of your tank should have alerted you to get someone in to check it over

AndyPK

get a plumber who can work on unvented systems.

as said, turn off the heating elements for a few hours and see if the flow drops down.

turn them back on for 45 mins if water cold

ssm90

Thank you all for the replies, sorry for the delay in getting back. You're all right I switched off the heating elements the overflow also stopped, it only seems to be occurring if the heating has been on for a while.

Even after reading all the well explained replies, I'm still not overly confident I understand everything- this is a new language to me. But it seems the overall consensus is that I need to get a plumber in.

This may be off topic but would you know if insurance would cover this? And if not, how much would it roughly cost to get this fixed? I've only moved into the flat a few months ago so I wasn't aware of any problems. I've already contacted the management company about this and haven't had a response.

I do have contents insurance on top of the buildings insurance for the whole block of flats, but I'm not sure if these would cover the costs, any ideas? Finally, is there any trusted website that I can use to get a certified plumber in to have a look?

Thanks again! Much appreciated.

System

ssm90 wrote: »

Thank you all for the replies, sorry for the delay in getting back. You're all right I switched off the heating elements the overflow also stopped, it only seems to be occurring if the heating has been on for a while.

Even after reading all the well explained replies, I'm still not overly confident I understand everything- this is a new language to me. But it seems the overall consensus is that I need to get a plumber in.

This may be off topic but would you know if insurance would cover this? And if not, how much would it roughly cost to get this fixed? I've only moved into the flat a few months ago so I wasn't aware of any problems. I've already contacted the management company about this and haven't had a response.

I do have contents insurance on top of the buildings insurance for the whole block of flats, but I'm not sure if these would cover the costs, any ideas? Finally, is there any trusted website that I can use to get a certified plumber in to have a look?

Thanks again! Much appreciated.

If you are renting the property, then resolving this problem is a matter for the owner not the tenant. sorry if I have got this wrong: your reference to a Management company has confused me.

To carry out a repair on an unvented system, you need a plumber that is certified to work on unvented hot water systems. This is known as a G3 annotation. Use this link to look for GSR engineers with this annotation in your area:

https://www.gassaferegister.co.uk/find-an-engineer/

Before you call out an engineer, you might like to try recharging the air gap. This is a simple procedure that doesn't involve any risk to you or your system. the following describes how to carry out the procedure:

To re-charge the air gap please use the following simple instructions:

Turn off the mains cold water supply.

Open the lowest hot tap in the property. Wait until the flow stops.

Hold open the temperature / pressure relief valve until the gurgling noise stops and water stops running from the tap and valve. (that is the black knob in your photo halfway down the LHS of the label near the top. You have to rotate the knob and hold it open)

Close the temperature / pressure relief valve; open the mains cold water supply to the Megaflo. When water flows from the hot tap close the tap

If water continues to drop or flow from the overflow the TPR requires attention. Switch off heat sources (immersion heaters and boiler), DO NOT turn off water supply.

https://www.youtube.com/watch?v=DFufKEIvbTo

ssm90

Hengus wrote: »

If you are renting the property, then resolving this problem is a matter for the owner not the tenant. sorry if I have got this wrong: your reference to a Management company has confused me.

To carry out a repair on an unvented system, you need a plumber that is certified to work on unvented hot water systems. This is known as a G3 annotation. Use this link to look for GSR engineers with this annotation in your area:

https://www.gassaferegister.co.uk/find-an-engineer/

Before you call out an engineer, you might like to try recharging the air gap. This is a simple procedure that doesn't involve any risk to you or your system. the following describes how to carry out the procedure:

To re-charge the air gap please use the following simple instructions:

Turn off the mains cold water supply.

Open the lowest hot tap in the property. Wait until the flow stops.

Hold open the temperature / pressure relief valve until the gurgling noise stops and water stops running from the tap and valve. (that is the black knob in your photo halfway down the LHS of the label near the top. You have to rotate the knob and hold it open)

Close the temperature / pressure relief valve; open the mains cold water supply to the Megaflo. When water flows from the hot tap close the tap

If water continues to drop or flow from the overflow the TPR requires attention. Switch off heat sources (immersion heaters and boiler), DO NOT turn off water supply.

https://www.youtube.com/watch?v=DFufKEIvbTo

I wanted to think this person but it seems they are no longer active.

This solution seemed to work initially, I followed the steps, the gurgling noise etc happened as expected but the water trickling never stopped...eventually I gave up and continued with the process.

However, the problem has resurfaced again. This time the waterflow is very high! Does this mean its completely bust now and I have to get someone to come into fix it?

I did want to point out something, in the steps above, it said to close the water inlet and let all the hot water out from the lowest tap of the house etc. which I did. Once it was drained and I restarted the water flow, the water immediately flowed out of the hot water tap in the bathroom. How is this possible? Wouldn't it take time for the heater and boiler to fill up? shouldnt there be a lag time? Or does the immersion heater work like a plate heat exchanger? If it is the latter, then shouldnt the water be heated instantly- why do I need to heat the water for a few hours before I can use it?

Thanks in advance!

Mr.Generous

When you drain it at the lowest point you then have to go and open all other taps to let water out and air into the pipes. The fact that water came out straight away probably means it hadn't drained down.

reeac

Mr.Generous wrote: »

When you drain it at the lowest point you then have to go and open all other taps to let water out and air into the pipes. The fact that water came out straight away probably means it hadn't drained down.

I have to recharge the air bubble in our system about once a year. It's a routine operation which I've been doing for the 21 years that we've lived here and the instructions are written on the side of the hot tank. The signal is the overflow of water from the external drain. It would be worthwhile, though, getting the system checked by a plumber who is certificated to work on unvented systems as components can seize or fail in other ways. I would say, incidentally, that 3.5 bars is too high ....better kept at around 2 bars although the system will run ok down to well under 1 bar.

matelodave

If the water that comes out is ever so hot then the thermostat on your immersion heater has failed and you need to get it replaced.

If the water is cold then it's likely that either the relief valve or the regulator has failed and possibly damaged the pressure vessl (the big white canister on top of your cylinder)

In any event, you are not able to sort it out without professional help, faffing about wont cure the problem