gas heating not working downstairs

[kieran5405]

Hi,

I have a gas heated 2 story house. The boiler works by electronic timer that divides the house into an upstairs and downstairs with a button for each. All was working well but now only the upstairs heating is working.

When i hit the boost button for upstairs the boiler kicks in (ie the flame comes on and it starts making some noise as always). Newbie...sorry. If i then stop the boost button for upstairs and let the boiler stop...then hit the boost button for downstairs the boiler doesnt kick in. The electronic timer looks fine as in the light comes on etc..

NB There is pressure in the pressure reader on the boiler as obviously upstairs works fine.

Thanks...

[David]

Your system is most likely separated with 2 two port valves, the one which regulates the downstairs might have stuck.

On the 2 port valve there is a little lever on the side, try pushing this to manual position and see if it works.The heating won't cut off though if it is left in the manual position.

[kieran5405]

cheers for that.

but i cant seem to see something like you mentioned.

where would this usually be...would it be beside the boiler downstairs??

[kieran5405]

In case this is of any use...the gas system boiler is a Vokera Mynute

16e...i.e. this is a large white box which has the pressure guage on it. Would the regulator be inside the box...theres a panel you can screw off. I cant seem to see anything else around the box/boiler that would do anything.

Thanks...

[kieran5405]

Hi,

After more examination, I found the plumping valve for downstairs (myson power extra mpe222). I found the manual override switch on the side and when i moved this to the manual position...then the downstairs radiators stated to heat up.

Does this mean that the myson unit just needs to be replaced...or can it be an indication of some other problem. How long do these units usually last...the house is about 4 years old.

Thanks...

[John Rumm]

The valves are not going to be in the boiler. They are often placed in airing cupboards, or perhaps in the loft space. How is your hot water heated? If that is also heated by the boiler then there will probably be a zone valve controlling that as well.

[Kevin Poole]

Do you have the necessary knowledge and equipment to check whether power is getting to the valve? If you can confirm that it's getting power when it should, then I believe the actuator can be removed without disturbing the wet side at all, and you can then either have a go at repairing it or replace it. Google "myson mpe222 actuator" and you'll find a supplier. It may use even use a common type of synchronous motor as sold, for instance, by Screwfix.

[Roger Mills]

The way these things work is that the timer and room stat open the valve and, once the valve is open, auxilliary contacts in the valve actuator close and tell the boiler to fire.

For some reason your valve isn't opening when it should. There are lots of possible causes for this, and some investigation is required in order to find the actual cause. The most likely causes are a failed motor in the actuator or the 'wet' part of the valve partially seizing - making it too stiff for the (not very powerful) actualtor motor to move. Other possible causes are a failed room stat or a discontinuity in the wiring between timer/stat/valve.

When you operated the over-ride, did the downstairs radiators get warm

*without* the upsdtairs ones being on, or only when they were on?

[kieran5405]

Cheers for all help.

As regards the room stat - its the 1 room stat that controls 3 areas - upstairs, downstairs and the water. So there are 3 different boost buttons - one for each area. Since the water and downstairs boost buttons on the stat both fire up the boiler and start the heating...it would seem to me that the room stat controller is not the problem. Does that sound right?

When I turn on the downstairs boost button and I look at the downstairs valve unit - the red power light comes on on the side of the valve unit. Would this mean that power is definitely getting to the valve?

When I operated the override - the downstairs rads did get warm without the upstairs ones been on.

I have looked in google at the actuator - can i change the actuator by just unscrewing the screws and replacing...or does water or something have to be turned off. I am a very newbie...sorry.

Thanks...

[AlanD]

That's unlikely to be room stat, it's the programmer.

The stat will be elsewhere downstairs with a temperature dial. And there will be another (probably the same make/model) upstairs. And another on the cylinder.

[Roger Mills]

Something doesn't sound right! The unit you describe sounds like just a

3-channel timer rather than a thermostat - unless there are 3 remote sensors connected to it. For example, to control the hot water, you need a thermostat (or at least a sensor) strapped to the HW cylinder so that it can shut the HW valve - and, in turn, stop the boiler - when the water is hot enough. Are you sure that there isn't a cylinder stat plus two room stats on the walls - one upstairs and one down?

Sounds promising.

By over-ride, you mean a lever which you move to open the valve - and you can feel/hear the gears whirling as you do so? Can you hear it closing again when you unlatch the lever? If so, it's almost certainly a failed motor in the actuator.

I'm not familiar with this particular valve/actuator - but most modern valves have actuators which can be removed and replaced - just by undoing a couple of screws - without spilling any water. If you *do* replace it, make a careful note of the electrical connections and connect the new one's wires exactly like the old one - colour for colour.

[kieran5405]

Sorry i was describing the programmer rather than the stat. There is a stat upstairs and downstairs.

By over-ride, you mean a lever which you move to open the valve - and you can feel/hear the gears whirling as you do so? Can you hear it closing again when you unlatch the lever? If so, it's almost certainly a failed motor in the actuator.

Yes this is how it works...so it does seem to be the actuator.

From looking on the web, I think it isnt too hard to change the actuator -

I'll go out to hardware shop and see if i can get an actuator and take a shot at changing it. Hopefully that will be the problem...as it seems to be this or the stat.

Is there some easy way to check whether it could be the stat?

Thanks...

[Roger Mills]

I doubt whether you'll get one at a hardware shop or DIY shed - a plumbers merchant would be a better bet.

Yes, if you can check that the valve's brown wire is at mains voltage relative to the blue wire when the valve should be open. If it is, the stat is ok. The fact that the neon comes on suggests that mains is getting through to the valve ok. [The document you cited says that the neon comes on when the valve is open - but my guess is that it comes on when the valve is

*told* to open, even if it doesn't!].

[David]

Sorry for making you discover the valves yourself.... I went to sleep.

[kieran5405]

Thanks for all help...I replaced the actuator, wired it up, said a prayer...and all worked!!!

In case this is of any help to anyone else... This actuator was very easy to replace. Two screws hold it to the pipe which controls letting the hot water in by whats called a spindle. The actuator screws easily off as one unit and is connected to the power by 4 wires. Its best to take digital photo of how these wires are connected (my newbie tip) or note in detail how they are connected. Turn off all power in house (my other newbie tip), remove old actuator wires...then wire up ur new actuator and attach to pipe by placing carefully over the spindle. Then turn on heat!

Thanks again...

[Roger Mills]

Good. Glad it's working again.

Whilst turning off all power is a reasonable precaution if you don't know exactly the heating is powered, it shouldn't normally be necessary - and might have undesirable effects on other equipment (computers, clocks, video recorders, etc.) which don't like losing their power supply.

The heating *should* be powered through a dedicated FCU (fused connection unit) spurred of one of the ring mains. Turning that off will isolate the system - boiler, pump, programmer, zone valves, etc. - without affecting anything else.

[Mine's actually fed via a 13A plug so that I can plug it into a generator in the event of a lengthy power cut].