I recently switched off the central heating, and since then, the hot water comes out luke warm !
I've turned up the thermostat, on the cylinder, to 75 (to see if that was the problem) and its made no difference.
The boiler is on and off all the time but obviously not heating the water to the correct temp.
What should I check next and how ?

Cheers ST

Is the system gravity or fully pumped, have you any motorised valves.

Mog

try turning the boiler thermostat up (to max if its fully pumped)

No idea which it is TBH.
Theres a large & small tank in the loft.
The cylinder is on the first floor, with the boiler on the ground floor.
Pump doesn't appear to work when switching the hot tap on.

We get hot water via the imersion heater at the moment - is that not linked to the thermostat ?

in the airing cupboard do you have a pump and 2 seperate valves or 1 possibly a valve with 3 pipes in it like a honeywell with a wire from it
if so then you have a fully pumped system
the immersion is seperate fromthe heating and has a thermostat inside where you can adjust the temp . set it to 60

I had a similar problem - the motorised valve that was connected to the contact thermostat on the side of the tank was knackered. Meant that no hot water was circulating through the tank even if the thermostat was saying "open" and the only thing heating the water was the immersion element. This has its own thermostat and is only intended as an auxilary.

Swapped the motor (do a search in this forum for my thread on this from about 6 months ago- great advice) and all was well.

Also had a lower 'leccy bill too!

Swapped the motor (do a search in this forum for my thread on this from about 6 months ago- great advice) and all was well.
The problem is that you don't know if it's the motor that's faulty, or the 3-way valve. If the valve is faulty (which IMHO is more likely, especially if you live in a hard water area), then at least part of the central heating system may need to be drained so the valve can be replaced.

It fairly easy to check - you can usually disconnect the motor from the valve, and see if it changes possition correctly when you switch between Hot Water Only/Hot Water + CH/None. You can also try to alter the valve setting manually to the "Hot Water Only" position, and see if you water heats up properly.

(Waiting for Mog to come back and say how much of a bad idea this is! IANOP!)

(Waiting for Mog to come back and say how much of a bad idea this is! IANOP!)


I hope that isn't a dig at me.......

I hope that isn't a dig at me.......
Not at all! It's just that unlike me, you normally know what you're talking about!

If your hot water is fine when the heating is on then its more than likely a diverter valve fault. If its a fully pumped Y plan system. Y plan 1 diverter, 1 pump.

We get hot water via the imersion heater at the moment - is that not linked to the thermostat ?

Does that mean you always use the immersion or have you had to resort to using it due to the lack of hot water from the boiler.

Mog

One thing i notice nobody has mentioned, I know you have turned your heating off but are any of the radiators heating? If so the valve/valves may be passing water into the wrong set of pipes ( so only half is going to the water tank and the other to the rads).

Sorry for the delay in responding. It was a bank holiday weekend, so beer had to be drunk ;)

The pump has two valves either side of it and a small box above it labeled mid position acutator.
The radiators arn't heating and we are using the imersion as a temporary measure.
As a test we've left the hot water on for extended periods and the water is getting hot !
Seems we may have to set the timings for longer periods which is strange considering everything was fine before switching the Central heating off :confused:

Any ideas or recomendations for good plumbers in the North West ?
Cheers
ST

By leaving the hot water on for an extended period you are just duplicating the heating time as though the central heating was on, it sounds as though there is a blockage in the mid-position valve or the coil in the cylinder preventing the full flow of heated water and transfer of heat. Or the coil/cylinder is scaled up preventing the transfer of heat again. A quick test to check the scale theory is to thump the side of the cylinder with the palm of your hand and listern to see if you can hear scale falling off and dropping to the bottom of the cylinder.

Mog

Cheers Mog :)
Bit late tonight so I'll give it a thump tomorrow ;)
Its a new house (2.5 yrs old) and in a very soft water area, so would scale build up so quickly ?

eh scooby towers.
yer 3 way valves bolloxed
wont be any scale not if its that new and soft water to boot
have a bash at doing it yourself, we'll all guide u through it.
piece of cake as long as you got a decent amount of room in yer airing cup

Why would you switch off your central heating?

Cheers Steppers - Plenty of room in the Airing cupboard.
I'm ok with spanners etc so long as I know which bit needs stripping :D.
Is the 3 way valve the one above the pump that has the actuator connected to it ?


Matt - its summer, hence the switch off ;):D

thats the 1 mr towers
tie up the ballvalve in the little tank in the loft
drain down heating - bleed rads
change your valve
turn off rad vents and drain cock
let the jolly ole ballvalve go

voila

Have you got a balancing valve on the return pipe (out of the bottom of the cyl. normally) they are usually a gate valve.
If you have got one,it could be virtually shut causing the flow to be restricted,check that its open by at least 2 to 3 turns.
You dont tend to get many hot water probs from a div. valve.
The divertor valve seems to be shutting off for the radiators,so we know that the ball/plate(depending on which type of valve) has movement and is sealing well.The synchron motor in the actuator isnt needed for the water heating,so we can rule that out.The only thing it could be is if it has a ball inside it,it could have swollen,causing a restricted flow-but its fairly unlikely.
On new systems,its usually somthing fairly simple.
Sounds more like some kind of restricted flow problem.

easy