3 port divertor hot case

[JayJay1978]

Over the last few days our heating system has developed a fault, when we select hot water the heating comes on.

The Danfoss (Type:HSA3) 3 port divertor valve in the airing cupboard feels quite hot to the touch on the top even though all 3 pipes are cold, I'm guessing its faulty but is there any way to test whether it needs a new head or just a synchron motor?

Oh, our set up is a combi boiler supplying heating to all rads, and DHW to new extension and gararge utility then vented cylinder feeding rest of house. I always thought this was a mid position valve but a google of the model number says its just a divertor.

Many thanks.

 

[D_Hailsham]

The Danfoss (Type:HSA3) 3 port divertor valve in the airing cupboard feels quite hot to the touch on the top even though all 3 pipes are cold, I'm guessing its faulty but is there any way to test whether it needs a new head or just a synchron motor?

...

I always thought this was a mid position valve but a google of the model number says its just a divertor.

Is it a HSA3 or HSA3D actuator? The Diverter is the HSA3D.

You can also tell from the cable. The diverter cable has four wires and the mid-position has five.

Which is it?

 

[mysteryman]

If the head is hot, it is being powered for central heating, and maybe or maybe not for hot water to the cyl as well. Check your programmer - it must be calling for central heating for this to be happening - unless there is a wiring error. That is quite possible, due to the nature of this installation.

 

[JayJay1978]

Thanks for replys, the number on the head is HSA3 and it has 4 wires.

I'm not at home at the moment but I have the old head with me, this head was obviously replaced a few years ago before we moved here and I found it yesterday at the back of the airing cupboard.

The one thats on now looks to have been on a few years though.

 

[D_Hailsham]

Thanks for replys, the number on the head is HSA3 and it has 4 wires.

I was including the earth wire in my count. I think it's best to go by the model number; which means you have a mid-position valve.

How a mid-position valve works gives you fault finding info.

 

[simond]

I thought you said all three pipes into the motorised valve were cold?

If this is the case, and if I have read your post correctly, then it is likely you have a fault in your combi, such as a failed diverter valve.

 

[Agile]

In the modes when the motor is powered in the valve the head will get fairly warm but never too hot to keep you hand on though.

Tony

 

[JayJay1978]

Many thanks for that I have a basic understanding of a standard Y plan but this addition of a combi takes some thinking about.

The combi is giving us hot water on demand and its heating the water in the cylinder, the last time I felt the top of the motorised valve head we were not calling for HW or CH so all 3 pipes were cold but the head was warm/hot.

I googled HSA3 and it told me it was a divertor.

http://www.uk-plumbing.com/Danfoss-...e-Actuator-Only-p-1394.html?source=googlebase

The wires are:
Grey
Blue
Orange
Brown/white

It has no earth wire, should it have?

 

[filsyn]

With the hot water only only on check the white wire in the 10 way for 240v using a multimeter, if no 240v then the body of the valve is passing, if there is 240v then disconnect white wire and check white wire for 240v if you have this on the wire on it's own the actuator head is faulty, if the terminal the white wire came from is has 240v the problem is elsewhere, call out a heating engineer.

Only attempt the above if you're competent with electrics.

You could just change the actuator and the valve body though.

 

[stardanny]

Many thanks for that I have a basic understanding of a standard Y plan but this addition of a combi takes some thinking about.

The combi is giving us hot water on demand and its heating the water in the cylinder, the last time I felt the top of the motorised valve head we were not calling for HW or CH so all 3 pipes were cold but the head was warm/hot.

I googled HSA3 and it told me it was a divertor.

http://www.uk-plumbing.com/Danfoss-...e-Actuator-Only-p-1394.html?source=googlebase

The wires are:
Grey
Blue
Orange
Brown/white

It has no earth wire, should it have?

That a mid position valve. I have one same in airing cupboard with same colour without earth wire.

If your system working ok, the valve will always change to heating port if the cylinder temp has reached temp and heating not calling for, and stay like that till cylinder call for heat then the valve will lost power / turn to hot water port.

This is normal.

The valve will always stay on if the cylinder temp has reached and the programmer heating and hotwater switched to off.

If you don't want the valve warm/hot all the time, turn power off, in the programmer baseplate, there a wire connect to HOTWATER OFF, disconnect that, put a choc-block on wire to make safe, it will stop the valve get warm/hot during off season. The only drawback is you will only have hot water only and hot water / heating and no heating only. The heating will still work even if the cylinder reached temp or not.

I've done this to prolong the life of my valve.

Hope this help.

Dan.

 

[D_Hailsham]

I googled HSA3 and it told me it was a divertor.

http://www.uk-plumbing.com/Danfoss-...e-Actuator-Only-p-1394.html?source=googlebase

That a mid position valve.

Stardanny is correct. If you read the link carefully it says "Suits Danfoss 3 port Mid Position Valves."

If your system working ok, the valve will always change to heating port if the cylinder temp has reached temp and heating not calling for, and stay like that till cylinder call for heat then the valve will lost power / turn to hot water port.

This is normal.

The valve will always stay on if the cylinder temp has reached and the programmer heating and hotwater switched to off.

Sorry, Stardanny, but this is wrong. If your system behaves like this it is wired incorrectly, or the valve has been installed the wrong way round.

Read the link I gave above.

 

[mysteryman]

No, he is not wrong. With the benefit of hindsight, I was also wrong in my earlier post when I thought it was a diverter, not a mid position or Y Plan valve.

A Y Plan valve will motor to CH only when the system is powered up with all thermostats satisfied or the prog set to all off.

 

[stardanny]

If your system working ok, the valve will always change to heating port if the cylinder temp has reached temp and heating not calling for, and stay like that till cylinder call for heat then the valve will lost power / turn to hot water port.

This is normal.

The valve will always stay on if the cylinder temp has reached and the programmer heating and hotwater switched to off.

Sorry, Stardanny, but this is wrong. If your system behaves like this it is wired incorrectly, or the valve has been installed the wrong way round.

Read the link I gave above.

Hi D_Hailsham, thanks for the link, useful info.
Strange, it happen on my system which is Y plan with Danfoss Mid pos valve, the valve cover got warm even the programmer not calling for heat. I thought the wiring might be wrong but in fact is correct, they are wire up to danfoss wiring diagram.

It only happen if both hot water / heating is on, the valve move to mid position, when hot water reached temp, the valve change to heating only, when heating reached temp, the boiler switch off, the valve stay open to heating port even with programmer HW/HEATING switched to off, for however long till hot water calling for heat will the valve open to hot water.

I think it only happen to Danfoss mid pos motor head and does not happen on Honeywell valve? Or are they all the same..?

OP, best is to have the wiring check out, and if it all correctly wire up, then it is normal.

Dan.

 

[mysteryman]

All modern Y Plan [mid position valves] work the same way. If the cylinder thermostat and room 'stat are both satisfied, the valve motors to the heating only position; it is mechanically stalled at the end of its travel, and the case will be warm or hot to the touch. This also applies if the programmer is in an all off position; the grey wire is live and the valve motors full travel as before.

This is perfectly normal.

The Honeywell website has an excellent explanation.

 

[stardanny]

The only way to stop this and prolong the life of the motor is to disconnect wire from HW OFF in programmer's baseboard, make safe end wire with choc-block. But this will lose Heating Only function but heating will still work with hot water on, reached temp or not. It will need a new programmer so when switching heating on also switch HW as well.

Dan.