Hot Hot Hot water - faulty Cyltrol Valve?

[Helg]

For a while our running water is scalding hot, read somewhere it could be a faulty Cyltrol Valve - as layman I never heard of it before, could not find a stat on hot water cylinder (32 yrs old, we have traditional indirect heating sytem). In addition there is a trickling overflow into small water tank - could that be result of water in hwt heating up too much and therefore pressure builds to release some water into overflow? I include photo of valve I spotted on a pipe near the hwt, is sits quite low

 

[Helg]

this is the valve (Cultrol Valve?) if found on a pipe close to bottom of hot water tank

 

[JohnD]

overflow into small water tank

do you mean an overflow trickling out of the tank? Or do you mean fresh water trickling into the tank from the fill valve?

Or trickling into the tank from the large copper pipe hooked over the top of it?

Post a photo please.

 

[JohnD]

View attachment 168393 this is the valve (Cultrol Valve?) if found on a pipe close to bottom of hot water tank

It might possibly be, though your picture is poor. There should have been a blue plastic knob to turn it (which probably broke because the spindle is seized). If you look at the flat base, there should be two brass "lugs" that prevent the knob rotating more than (from memory) about 45 degrees.

Funnily enough I had one some years ago
https://www.diynot.com/diy/threads/cyltrol-valve.109746/

It is very old and a replacement valve is expensive. Better to modernise it to a fully pumped system. I did. Or at least add Cylinder Thermostat control (this is a wiring change) It looks like you have multiple problems. Unless you are very fond of DIY plumbing, you'd do better to ask around for a well-recommended local plumber. You need not touch the boiler, so it does not have to be a Gas-safe person. Older plumbers will have seen lots of these.

I bought a new Cyltrol valve, didn't need it in the end, sold it for around £80 on ebay. They are seldom used now. There are much better ways.

If you HW is very hot, try turning down the thermostat/temperature knob on your boiler. Your boiler is probably also very old and may have a temperature problem. It's hard to see how you will get round of this without spending a fair bit.

p.s.
don't turn the spindle or it will leak

 

[HERTS P&D]

Has the stat fallen of f the cylinder, post a picture of the cylinder.

Andy

 

[Helg]

Thank you Herts and John, you guys deserve a medal. Pull my hair out - spoke to FOUR (!!) plumbers/had them in my house, all I REALLY would love to know is this: What steps do I have to take to sort out the system
SYSTEM NOW: Indirect system, Potterton boiler works fine despite age (32 ys), Hot water cylinder in Airing Cupboard, Large and small water tank in loft above, installed in 1987
PROBLEM: small trickle of overflow into small tank, happened after I shut down water into house by mistake, could have created a small crack in hwc spiral - that's at least what was the consensus
but the other recent problem is: running hot water scaldingly hot - one of the plumber said it could be this Cyltrol valve not working, creates too much heat which leads to water being released into overflow, so maybe no split in cylinder
SOLUTION: PLEASE LET ME KNOW WHAT YOU WOULD SUGGEST TO YOUR BEST FRIEND - shall I just get a new hwc? can afford it, price range 1000- 1500?
Please tell me the exact steps - want to keep boilder, old system (small/large tank) but put in a hwc that is future proof in case new owners (I might sell up in the next few months) want to further improve/modernise system
read somewhere a fully-pumped system would be best solution, but don't understand what that involves - and the plumbers I have need to be told exactly what to do so there is no screw up
THANKS A LOT!!!!

 

[ianmcd]

Do you have an electric immersion heater that may have been inadvertedly switched on

 

[undertrained]

It has been asked you post a photo of cylinder, if it doesn’t have a thermostat it will be working from the boiler thermostat only. If your cylinder isn’t scaled up then get a cylinder thermostat fitted. As for the overflow issue it could be a crack in the coil (spiral as you call it), it I would be expecting this to overflow outside constantly. However you’re describing it filling into small tank so filling valve letting by?

 

[JohnD]

@Helg it would be really great if you would answer some of the questions you have been asked.

 

[Helg]

Immersion heater is switched off, overflow goes into small tank is regular, but very little, maybe one bucket a day, first thought it has to be leak in coil, but after the hot water problem came into the picture and i did bit of research on it the possibility that too much hot water in cylinder created the overflow (in order to release this excess of heat) crossed my mind, maybe no leak in coil after all
alternatively just a simple question:can I just install a new cylinder, keep traditional indirect vented system/boiler/two tanks? one plumber said i would have to switch to pumped system (what does that mean?, not that it puts too much pressure on existing/old pipes and they start to leak)
cannot add pic of cylinder, all wrapped up in red insulation, but felt all around, no stat anywhere to be felt
THAAAANKS

 

[ianmcd]

It is very simple, your system is very basic, the temp of the HW from your tap can not exceed the temp of the water leaving your CH boiler, turn your boiler off and see if your HW is still hot

 

[dilalio]

OP... Help us to help you. You risk making the wrong decision by sticking with your preconceptions which will cost unnecessary expense.

 

[Nige F]

View attachment 168393 this is the valve (Cultrol Valve?) if found on a pipe close to bottom of hot water tank

I don't think that's a cyltrol - having fitted them in the 70's - John D's link shows them (offset bodies not straight )

 

[Nige F]

Thank you Herts and John, you guys deserve a medal. Pull my hair out - spoke to FOUR (!!) plumbers/had them in my house, and the plumbers I have need to be told exactly what to do so there is no screw up
THANKS A LOT!!!!

Have the plumbers actually ever fitted a cyltrol ?

 

[Nige F]

I include photo of valve I spotted on a pipe near the hwt, is sits quite low

Is there a pipe directly above where that one goes into the cylinder - it could be as much as threequarters up the cylinder.