Radiators coming on with hot water question?

[Russdeebrown]

Hi,

Its starting to warm up now so i have turned my radiators off via the central heating controls. I now have the water coming on a couple of times a day. I have noticed though that the radiators are still getting hot when the hot water comes on.

Looking at the mid position actuator (made by IKON), when the hot water comes on, the position switch doesnt move fully all the way over to the W sign. If i only put the heating on, the position switch moves fully over to the H sign.

Do i have a faulty mid position actuator? By the position switch not moving fully over to the W sign, is it leaving the valve open a little for the hot water to get into the radiators?

Will this be having an effect on my gas bill?

Your help is appreciated.

Russell

 

[Russdeebrown]

Any help?

 

[AlanE]

Any help?

Slow down and give people a chance two hours on a weekday! You might be sitting at home but many like me who give advise here are out working, repairing boilers and heating systems for money to put food on the table.

I've just glanced at the forum and about to sit down for dinner. Will post suggestions later.

 

[twgas]

I would be suspecting the three port valve has dirt on the valve and seat so not shutting off properly. More than likely need a complete valve but as we know nothing about your system its not easy to be sure

 

[themadprofessor]

I would be suspecting the three port valve has dirt on the valve and seat so not shutting off properly. More than likely need a complete valve but as we know nothing about your system its not easy to be sure

I have had this issue for years, and even replacing the three port valve completely did not solve it. Now with the gas prices so high I would like to get to the bottom of the issue.

Could it be some sort of convection causing a reverse flow into certain radiators. I notice that about half the radiators get hot. I have a bungalow with all the CH pipes running in the loft, and the individual pipes to radiators drop through the ceiling adjacent to each rad. All of the rads are equipped with thermostatic valves, but in addition I have a Potterton programmer with temperature set back, so the radiators where the stat is located have either had the thermostatic element removed or fully opened.

I would be grateful for any suggestions as how to (a) find out what is happening to cause them to heat up, and (b) how to remedy the situation.

One idea I had was to find the flow pipes after the "Y" piece and insert solenoid valves here wired to the appropiate contacts on the programmer so that both flow AND return are closed off when the relevant thermostat closes. Surely this would eliminate the issue, however could it cause pressure build up leading to other problems?

Thanks Chris

 

[gas4you]

Yes you can get a 'reverse flow', especially if the return pipes are not all commoned back to one spot. It is often due to the return water from the HW cylinder circuit 'drifting' up the rad returns.

I have even had, only once though, a flow set up within a single pipe, due to convection etc, or something.

Way above my head, but fixed it.

 

[themadprofessor]

Yes you can get a 'reverse flow', especially if the return pipes are not all commoned back to one spot. It is often due to the return water from the HW cylinder circuit 'drifting' up the rad returns.

I have even had, only once though, a flow set up within a single pipe, due to convection etc, or something.

Way above my head, but fixed it.

The 1000 dollar question is "How" did you fix it?

Chris

 

[doitall]

One problem is not the same as another.

You should start another thread instead of hi-jacking the OP's.

 

[SirBodgeAlot]

Hi,

Its starting to warm up now so i have turned my radiators off via the central heating controls. I now have the water coming on a couple of times a day. I have noticed though that the radiators are still getting hot when the hot water comes on.

Looking at the mid position actuator (made by IKON), when the hot water comes on, the position switch doesnt move fully all the way over to the W sign. If i only put the heating on, the position switch moves fully over to the H sign.

Do i have a faulty mid position actuator? By the position switch not moving fully over to the W sign, is it leaving the valve open a little for the hot water to get into the radiators?

Will this be having an effect on my gas bill?

Your help is appreciated.

Russell

Hi Russell,

Sounds like the valve should go all the way over to W if only hot water demand is present, as you suggest.

Assuming your system is "Y-Plan" i.e. hot water from the boiler is diverted to the rads or cylinder or both, depending on demand, by your Ikon 3-position diverter valve, I would suggest looking at the following -

1. Check your wiring configuration, you may still have a 240v feed on the central heating demand wire of the valve even when you only have a call from the hot water system stat/timer/programmer - if it is wired incorrectly. (you can get wiring schematics from Honeywell, I'm sure there are links or even the diagrams elsewhere on this site)

2. The valve may be stuck, turn off power to the system and see if you can move it manually over the full stroke, or remove the actuator and move the valve with pump pliers or adjustable spanner over full stroke. If it is stuck, change it.

3. As you say, may be a duff actuator, but check all the above first. If 1 and/or 2 is a problem, changing the actuator won't help you.

Yes, it will effect your gas bill due to unnecessary heating of rads, this uses energy that could of been used to heat your hot water up quicker.

Hope this helps.

Rob

 

[AlanE]

If the valve is one where you can replace the actuator then remove the old one and check if you can turn the spindle from the valve section EASILY.

 

[gas4you]

The 1000 dollar question is "How" did you fix it?

Chris

Re-piped it back to the common return

 

[Russdeebrown]

Hi,

Hi Russell,

Sounds like the valve should go all the way over to W if only hot water demand is present, as you suggest.

Assuming your system is "Y-Plan" i.e. hot water from the boiler is diverted to the rads or cylinder or both, depending on demand, by your Ikon 3-position diverter valve, I would suggest looking at the following -

1. Check your wiring configuration, you may still have a 240v feed on the central heating demand wire of the valve even when you only have a call from the hot water system stat/timer/programmer - if it is wired incorrectly. (you can get wiring schematics from Honeywell, I'm sure there are links or even the diagrams elsewhere on this site)

2. The valve may be stuck, turn off power to the system and see if you can move it manually over the full stroke, or remove the actuator and move the valve with pump pliers or adjustable spanner over full stroke. If it is stuck, change it.

3. As you say, may be a duff actuator, but check all the above first. If 1 and/or 2 is a problem, changing the actuator won't help you.

Yes, it will effect your gas bill due to unnecessary heating of rads, this uses energy that could of been used to heat your hot water up quicker.

Hope this helps.

Rob

Rob,

Is the actuator fairly easy to change yourself.

You say that the valve may be stuck. Is this i one behind the actuator?

I take it that behind the actuator is a valve of some sort and the actuator electronically controls the valve by turning it in a certain direction? Can i take the actautor off easy enough to check and then replace it?

 

[Russdeebrown]

Right,

Sorry bit of an idiot.

I checked the actuator and realised how easy it is to take on and off.

Checking the valve behind, there is some movement but how much is there meant to be?

If its closed position is 12 o'clock the only movement is to the left to about 9 o'clock. Should it move the other way? (to the right) or is this its normal movement.

Cheers guys

 

[gas4you]

What valve is it? Some only have a very small movement, eg Honeywell, whilst some eg danfoss will rotate 360 and be controlled by the head.

Is it 'stiff' to turn?

 

[Russdeebrown]

No not stiff to turn. Believe it is by IKON.

Spoke to the fella who fitted it and he thinks it could be the valve as sometimes the insides of the valve go and it could be letting water through from the Hot water to the heating. Does that sound right?