Water red hot, but boiler and immersion heater are off?

gentlepurr

As per thread title, since last night the water in my hot water tank is HOT!! I had to turn the heating off at the rocker switch as the hot water was on constant at the control panel and the panel was 'frozen' and wouldnt move. I never/rarely use the immersion heater but i did check that this was off, before i went to bed last night. Water was still hot this morning, and pipes to the tank were red hot as well. Called a plumber in and he has fitted new control panel (for water and CH) and a new electric box in the airing cupboard, but he left at 4.30 this afternoon and the pipes are still red hot, as is the tank, what bit i can feel at top of jacket.

Obviously the new stuff hasnt made a scrap of difference, but i do remember once that similar happened with the radiators being stuck on permanently, and this was due to a valve being stuck. I had thought that it was the valve the plumer/CH Engineer was replacing in the airing cupboard, but its a box thats on the wall with electric wires running from it, not the box thats attached to the water pipes....

please can anyone give me their thoughts?? I did ring the plumber back and he said it would take a long time for the pipes to cool down, and that 'he would call me at 8am tomorrow to check' (have to admit im a bit sceptical about that) but they are still red hot now.....

Thanks for reading

gp xx

Myser

Did he check if the hot water zone valve was stuck open?

They look something like this:



Or this:



When you say control panel, do you mean the programmer? Where you set the times for the heating and hot water to come on?

You need to get the plumber back if it is still a problem. Have you paid yet?

keystone

Open a hot tap or two and run some water off. Run a bath if necessary and use it then you won't have wasted it.

Can you hear the Cold Water Storage Tank filling when the hot taps are open?

If you can get to the CWST in the roof stick a finger in and make sure its cold and not hot.

Knock the breaker off in the Consumer Unit. for the immersion heater to completely isolate it.

Even if the boiler is off he is right it will take time to cool down.

Try and be a bit more specific about what he has changed. Was it the cylinder stat? Whether he changed it or not what temperature is the dial on it set to?

Cheers

gentlepurr

Thanks both for your replies.

Myser, he has changed the valve, the new unit looks like the one in pic 2, and yes, i meant he has changed the central heating and hot water programmer.

keystone, he has set the stat on the hot water cylinder to 50 deg, it was set around 60 before.

Pipes are still hot this morning

keystone

Humour me on the other stuff huh?

Have you used any hot water this morning?

Does the CWST fill and the the boiler fire up when you do?

Cheers

gentlepurr

Morning keystone thanks for being quick off the mark again!

Bit of a headless chicken job here this morn cos i'm carer to two people as well, so trying to do a zillion things at once and its a bit of a mammoth task to get to the cwst in the loft so about to run the tank off in a min, plumber has just called me back ( i shouldnt have been so damn cynical about him should i ) so going to see what a few baths and showers and running the remainder off does.

will report back later

thanks

xx

Mr_Ted

Its never easy to diagnose a problem after the horse has bolted, but

Re the programmer - it is extremely unlikely that a programmer has caused an overheating problem, that may just be coincidental.
It may also have been unnecessary to change it as some of the older programmers were susceptible to freezing due to a battery problem which could be cured by cleaning the contacts or replacing just the battery, but its too late now:(

The 3 port valve IS the probable cause?
The high temperature however will then, if it was the valve, have only reached the temperature set on the boiler, and would unlikely to have reached a point of boiling (that would only occur if the boiler stat was faulty), but it would be hot enough to scald!

The issue with the F&E tank is probably irrelevant as if excess heat had affected this the overflow would have run, as it would be that that is the warning of expansion!

Re the temperature, there will be pipes that will feel extremely hot to the touch as the boiler should be set to supply water to the system at approx 70 C.
The cylinder will also feel hot to the touch, but 60 C is the normal set point, as at this temperature it is deemed to be high enough to pasteurize the DHW system to kill all bugs that can occur.
Anything lower may not do that due to stratification of the water temperatures within the cylinder.

If water supplied too hot to the taps is an issue due to care needs, it would be advisable to have blender valves fitted at the outlets, as this would lower the temperature at the taps only for safety of use.

To anyone who has issues due to hot water overheating the simple solution, should it occur, is to switch the boiler off at the boiler and the local electrical isolator, and run the water so that cold water is entering the system to cool it!

cyclonebri1

Mr_Ted wrote: »

Its never easy to diagnose a problem after the horse has bolted, but

Re the programmer - it is extremely unlikely that a programmer has caused an overheating problem, that may just be coincidental.
It may also have been unnecessary to change it as some of the older programmers were susceptible to freezing due to a battery problem which could be cured by cleaning the contacts or replacing just the battery, but its too late now:(

The 3 port valve IS the probable cause?
The high temperature however will then, if it was the valve, have only reached the temperature set on the boiler, and would unlikely to have reached a point of boiling (that would only occur if the boiler stat was faulty), but it would be hot enough to scald!

The issue with the F&E tank is probably irrelevant as if excess heat had affected this the overflow would have run, as it would be that that is the warning of expansion!

Re the temperature, there will be pipes that will feel extremely hot to the touch as the boiler should be set to supply water to the system at approx 70 C.
The cylinder will also feel hot to the touch, but 60 C is the normal set point, as at this temperature it is deemed to be high enough to pasteurize the DHW system to kill all bugs that can occur.
Anything lower may not do that due to stratification of the water temperatures within the cylinder.

If water supplied too hot to the taps is an issue due to care needs, it would be advisable to have blender valves fitted at the outlets, as this would lower the temperature at the taps only for safety of use.

To anyone who has issues due to hot water overheating the simple solution, should it occur, is to switch the boiler off at the boiler and the local electrical isolator, and run the water so that cold water is entering the system to cool it!

Sound advice, there will always be some means of shutting down the system, but don't waste the water, as KS says, wash something, yourself or otherwise.

macman

Sounds like your plumber is just adopting a a 'swap everything out until it works' approach, rather than proper fault-finding.
At your expense.

cyclonebri1

macman wrote: »

Sounds like your plumber is just adopting a a 'swap everything out until it works' approach, rather than proper fault-finding.
At your expense.

I call it a scatter gun approach, :D

keystone

macman wrote: »

Sounds like your plumber is just adopting a a 'swap everything out until it works' approach, rather than proper fault-finding.
At your expense.

I must admit I thought that last evening but allowed "benefit of doubt" to creep in until we get more info.

Cheers