Central heating info please.

[ipbr21054]

I'm staying at my sisters and noticed that the hot water heats up for an hour in the morning & at night which is is normal.
But
At the same time I've noticed that the radiators also get hot.
Water goes off and then the radiators cool down until the water heats up again later on.

Is the item shown in the supplied photo at fault or please advise.
Thanks.

 

[muggles]

That's certainly where I'd start looking

 

[ipbr21054]

Is there any way to test or eliminate it to see if when the hot water comes on the radiators don't etc.

 

[Mottie]

Sounds like the valve or valve motor is faulty and not shutting off the central heating side of the system, assuming the heating and room thermostat are switched off.. What are the heating times and room thermostats set at? Is that valve set manually open?

 

[muggles]

Let the system go cold, then turn on for hot water only. Touch the pipes coming out of either side of the valve to see whether it's one or both that are getting warm

 

[stem]

A 3 Port valve when at rest, is pulled by a strong spring to the 'hot water' only position, (i.e. the central heating port is closed) and they are driven by the motor to the 'central heating' position, so it would be unusual for them to fail and produce the symptoms you describe.

Although rare, if a mechanical fault has occurred such as the spring breaking, or a foreign object is blocking the central heating port so that it doesn't close properly, what you describe may happen. Sometimes though installations have been altered or modified wrongly which has created faults, or even wired incorrectly from their installation and so have never worked properly.

Electrical troubleshooting can be difficult with the three port valve. You need to have a good knowledge of electrical circuits and a multimeter to check it out. There is a very helpful series of diagrams here. by selecting the various 'Y Plan' settings you can see what parts of the circuit should be energised and when.

 

[ipbr21054]

Let the system go cold, then turn on for hot water only. Touch the pipes coming out of either side of the valve to see whether it's one or both that are getting warm

Everything is cold.
You say turn on for hot water.
You mean from the tap or check when the boiler heats up for hot water.
Sister isn't here until 6 etc

 

[Mottie]

You need to press the override button or set the hot water on constant to fire the boiler up to heat the water in the cylinder. You may have to run the hot taps to make the boiler thermostat to kick in. Not being funny mate but from the questions you ask, it kinda sounds like you haven't got the faintest clue about heating systems. I'm not a plumber by any means and I wouldn't know how to electrically fault-find but I think I'd be able to get an idea of where the problem is and replace a valve or get someone in to do it if it was anything electrical. It sounds to me like even if you diagnosed the problem, you'd have a battle on your hands putting it right. I know this is a DIY forum but I really think you should consider calling a heating engineer out to look at it. Good luck.

 

[ipbr21054]

I'm out at present but when I get home around 6 ish I think the boiler will be already at the time it heats the water up.

Can I just feel pipes then ?

 

[stem]

I'm assuming from your description, that the heating isn't set to be 'on' and the radiators are just heating up when 'hot water' is selected. So, is it possible that the valve's manual lever has been moved and latched in the open position?

 

[ipbr21054]

Just to answer a piece of advice given above.
I touched the 3 pipes that the valve is connected/sat on when the hot water wasn't heating up. It was say slightly warm 3/10.
Around 6 when the water heats itself up I gave it 10 minutes before I went and touched them. This time a lot hotter say 8/10.
The model of the valve is Danfoss HSA3

As I look into the airing cupboard the writing on the top of the valve is at the top rear of the case.
It then looks like Man is in the left & Auto is in the right. Now you mention lever etc I can feel but not see which I think is a flat metal bar over to the Man side.

 

[Mottie]

Well, switch it to auto then and see what happens. Is this a wind up?

I wrote this the other day. ".....Is that valve set manually open?"

Are you reading the replies?

 

[ipbr21054]

Why a wind up, I read all replies but maybe overlooked it etc.

So moving over to auto what should happen.

When hot water comes on to heat at 6 radiators will do nothing.
Radiators will only warm up when room stat turned up.

Would that be correct.

 

[stem]

Radiators will only warm up when room stat turned up.

That sounds perfectly normal to me, as long as the central heating is also set to be 'on' at the programmer. Is it?

 

[Mottie]

Moving it to auto will (if the valve is working) give you hot water, heating or both at whatever times the programmer is set at and only when the controlling thermostats (room and hot water cylinder) demand it.

Can you post a picture of the controller?