Hot water too hot, temp regulator not working?

[Rudy]

We have an old open vented central heating system I believe. Water tanks in the loft and airing cupboard, baxi back boiler downstairs in the living room. It's been fine since we moved in (6 month ago), but recently I noticed hot water is much hotter than usual. There is a small regulator next to the water tank in the airing cupboard in our master bedroom which can be turned clock and anticlockwise from 1 to 8, we've always had it set to 2 as that gave us the right temperature, but now whatever I set hot water comes out very hot 😕. BTW heating has been off for all summer and timer is set to heat water for 1 hr in the evening. Would replacing that regulator fix the problem, do we need to drain the system for that, how much would it cost? Appreciate any advice, many thanks.

 

[doitmyself]

There is a small regulator next to the water tank in the airing cupboard in our master bedroom which can be turned clock and anticlockwise from 1 to 8

Is the regulator attached to the pipe going into the hot water cylinder (tank)? If so, it's a thermostatic valve and the chances are it has gone wrong. They are not the most reliable or accurate way of controlling the water temperature. You can still get them but they are expensive.

 

[Rudy]

Is the regulator attached to the pipe going into the hot water cylinder (tank)? If so, it's a thermostatic valve and the chances are it has gone wrong. They are not the most reliable or accurate way of controlling the water temperature. You can still get them but they are expensive.

Thank you for your replay.
Yes, it's attached to the pipe going into the hot water cylinder. So is replacing the thermostatic valve the only way to fix this problem (and btw would we have to drain the system to do that), cause if you say they're not reliable or accurate, than maybe there is a better way to do it.

 

[gorbsteruk]

Hi Rudy , you dont happen to live at Sutton Maddock do you ?

 

[Rudy]

Hi Rudy , you dont happen to live at Sutton Maddock do you ?

nope, I'm in Essex😎

 

[doitmyself]

Yes, it's attached to the pipe going into the hot water cylinder. So is replacing the thermostatic valve the only way to fix this problem (and btw would we have to drain the system to do that), cause if you say they're not reliable or accurate, than maybe there is a better way to do it.

It sounds as if you have a gravity HW, pumped heating system. If you do, the pipes going into the side of the HW cylinder will normally be 28mm.

Does you heating control allow you to have the HW and CH on at separate times in the winter? If it doesn't, you definitely have gravity HW, pumped CH.

The cheapest solution, but not the best, would be to replace the broken valve by a motorized valve controlled by a thermostat on the side of the HW cylinder. This would also allow you to have separate HW and CH times, provided your timer is suitable.

A better solution would be to convert the system to fully pumped, which means new pipework at the boiler and cylinder as well as a motorized valve and cylinder thermostat.

I don't know how long you intend keeping the back boiler but, when you change it, you will have to convert to fully pumped - Building Regulations.

Do you intend doing the job yourself? If so, pics of the airing cupboard would be helpful as well as an inventory of all the components (excluding boiler, rads and tanks/cylinder). Then you will get instructions.

 

[Rudy]

It sounds as if you have a gravity HW, pumped heating system. If you do, the pipes going into the side of the HW cylinder will normally be 28mm.

Does you heating control allow you to have the HW and CH on at separate times in the winter? If it doesn't, you definitely have gravity HW, pumped CH.

The cheapest solution, but not the best, would be to replace the broken valve by a motorized valve controlled by a thermostat on the side of the HW cylinder. This would also allow you to have separate HW and CH times, provided your timer is suitable.

A better solution would be to convert the system to fully pumped, which means new pipework at the boiler and cylinder as well as a motorized valve and cylinder thermostat.

I don't know how long you intend keeping the back boiler but, when you change it, you will have to convert to fully pumped - Building Regulations.

Do you intend doing the job yourself? If so, pics of the airing cupboard would be helpful as well as an inventory of all the components (excluding boiler, rads and tanks/cylinder). Then you will get instructions.

The timer allows only constant on, timed or off settings, and with the temp control in the hall downstaires near the kitchen I can switch off the heating. That's how it is now. Hot water on timer and heating is off. I don't think I can have the heating on and hot water switched off. From what I was able to find on different websites the hot water cylinder has pipes going through it that heat the radiators, so I'd imagine hot water is neccessary for the heating system to work. But I'm no expert and I could be completely wrong. Nevertheless, I not going to try to repair it myself (we have hot water, just little bit too hot and we have to add cold water when filling the bath, so it's not critical, just a nuisance) and replacing the whole system simply isn't in my budget right now

 

[washer]

Always worth checking that you havent accidentally turned your immersion heater on