Errr....do I have gravity fed or fully pumped system??

[s79]

Very silly question but how do I work out what type of system i've got??

I'm currently swapping over the potterton controller/timer as the sliders have worn out (again), going from an EP2002 to an EP2.

One of the initial settings the new controller needs is knowing wether the system is gravity fed or fully pumped.

Now I'm "99%" certain it is gravity fed as it is a very old system (25+ years old), but im thrown by:
a) the fact i have a pump connected to the hot water tank
b) only two pipes coming out of the top of the boiler

(told you it was a silly question)

Anyway here us a pic of the boiler and pipework:
http://www.flickr.com/photos/98549025@N05/11099160094/in/set-72157638141247555

Here is a pic of the airing cuboard with the header tank, middle tank? (dont know what this does?), Insulated hot water tank:
http://www.flickr.com/photos/98549025@N05/11099251073/in/set-72157638141247555

Here is a close up of the pump:
http://www.flickr.com/photos/98549025@N05/11099143256/in/set-72157638141247555

Note - on the controller we've always had to switch the hot water on at the same time as the central heating in order to get the CH to operate.

Thanks in advance.

 

[Galoka]

It's not silly to ask questions if you aren't sure.

Anyway, it's a fully pumped system by the looks of it. The thing above the pump is a valve to direct the water to the CH or to heat the HW..

 

[PrenticeBoyofDerry]

I think the fact you have a pump and port valve, kinda answers your question.

 

[aesmith]

Here is a pic of the airing cuboard with the header tank, middle tank? (dont know what this does?), Insulated hot water tank

Looks like Cold Water tank at the top, not really visible. Feed and Expansion tank underneath, above the hot water tank. F&E tank supplies the water that circulates though the boiler, radiators etc (not the water you draw from the hot tap).

The system looks like fully pumped with three position valve, sometimes called "Y Plan". There's an animated explanation here ..
http://octaveblue.co.uk/c_heating/

It should be able to work heating without the HW needing to be on, but we'd need to know more about your system to comment. Different manufacturers have different ways of wiring up.

Tony S

 

[neiltheplumber]

It is fully pumped. The diverted valve is the main giveaway as pump will pump around the heating and cyclinder coil. Open vented system of course.

 

[s79]

Many thanks for the replies guys, much appreciated. It looks like a unanimous vote for pumped then!

Although....having said that... im still a little confused!!! As a family friend who is (genuinely) quite plumbing/heating savvy, and has seen my heating system first hand just recently, is convinced the system is gravity fed!

He thinks the pump is assisting, and that maybe its not a "fully" pumped system. Is there a difference between pumped and fully pumped???

Sorry for being a pain, Im sure im probably more of a big deal about this than i should!

I will try and post a few more pics shortly of the airing cupboard, the pump, the valve etc

Anyway one final question, on the new potterton controller what would the safest setting for now - gravity fed or pumped?

 

[Galoka]

Sorry, but your friend is talking rubbish.

As for the programmer, set it on pumped (I suspect the previous programmer was set for gravity, if it doesn't operate the CH and HW independently, then might need to check how things are wired.

 

[ianmcd]

you definately have a fully pumped system but check that the origional programmer had a wire connected to the HW off terminal as this is the most common wiring up fault of a Y plan system, if it didnt have one then you will have to run one to get your new programmer to operate correctly

 

[s79]

Again, many thanks to everyone who's replied, and apologies for my slow reply, was away for the weekend, so still not had chance to fit the controller! Will connect it shortly and set it to fully pumped for now.

Although...now I'm getting the impression the heating system has run for 25+ years with the hot water running at the same time unnecessarily for all that time!! Is that right???

What actually dictates whether a system can run the CH independently of HW? The valve/divertor near the pump? The controller?

Here's some more pics of the system for info, not in any particular order, but they cover the whole airing cupboard, the header tank, the , the hot water tank, valve and the pump.

Airing cupboard
http://www.flickr.com/photos/98549025@N05/11190285573/in/set-72157638141247555

Header tank (the top one)
http://www.flickr.com/photos/98549025@N05/11190276283/in/set-72157638141247555

Expansion (?) tank - the middle one
http://www.flickr.com/photos/98549025@N05/11190173996/in/set-72157638141247555

Pipework between expansion tank and hot water tank
http://www.flickr.com/photos/98549025@N05/11190169344/in/set-72157638141247555

The valve/divertor
http://www.flickr.com/photos/98549025@N05/11190268033/in/set-72157638141247555/

nb. the switch on the valve is set to "MAN" rather than "OPEN"


EDIT - Sorry, Ianmcd, just properly read your last post, guess this is what i need to check in order to run CH & HW seperately?

Also what did you mean when you said i need this to get my new programmer to work "correctly"? My replacement controller is a straight swap for a newer version (Potterton EP2002 to EP2)

you definately have a fully pumped system but check that the origional programmer had a wire connected to the HW off terminal as this is the most common wiring up fault of a Y plan system, if it didnt have one then you will have to run one to get your new programmer to operate correctly

 

[ianmcd]

yes it is a straight swap but if you dont have a wire connected to the HW off terminal (very common wiring mistake) then no matter what programmer you replace the existing one with it will not work correctly

 

[s79]

What/where is this "HW Off" terminal? Im assuming this is not referring to the controller but actually how the heating system is physically wired up?

For info here is the wiring instructions diagram for the Potterton EP2 controller:

http://www.flickr.com/photos/98549025@N05/11203007903/

P.s. Obviously im just a budding novice when it comes to heating and plumbing, so feel free to dumb down any replies!

 

[ianmcd]

are there any wires connected to terminal 1 on the backplate?

 

[Alfie25]

ianmcd has this spot on. I have a 'fully pumped' system too but the programmer is set to Gravity Fed on the jumpers on the back as when British Gas installed it, they did not run a new cable to the programmer for HW off. Obviously this meant less work for them and most customers seemngly didn't mind. Personally I would call it a disgrace.

With mine, once the cylinder stat is satisfied, the 3 port valve goes from HW and CH to CH only, however the HW light on the programmer stays lit.

From what you've said, yours does not have the HW off wire to the programmer and so you will need to set the new programmer to Gravity Fed.

 

[s79]

I've installed the new controller but not had a chance to test it yet as I've been changing radiators (another separate issue!)

Here is a picture of the back plate, prior to installing the new controller:
http://www.flickr.com/photos/98549025@N05/11208638155/
(nb. the lettering reads A B C D N L 1 2 3 4 5)

Here are the full wiring instructions from potterton for the EP2 controller:
http://www.flickr.com/photos/98549025@N05/11208816345/lightbox/

Alfie25 - sorry im being a really thick here but are you saying now I've installed the new controller and set it to fully pumped i should be now be able to run CH and HW independently? Or do I still need to "physically" connect a "HW off wire"? If so what will that involve on the back plate? I'm ok with wiring, its just the understanding of the configuration that confuses me.

It makes me wonder how common this installation is around the UK and how unnecessarily wasteful it is/has been?!?

 

[Alfie25]

Alfie25 - sorry im being a really thick here but are you saying now I've installed the new controller and set it to fully pumped i should be now be able to run CH and HW independently? Or do I still need to "physically" connect a "HW off wire"? If so what will that involve on the back plate? I'm ok with wiring, its just the understanding of the configuration that confuses me.

It makes me wonder how common this installation is around the UK and how unnecessarily wasteful it is/has been?!?

That 1st link just goes to a yahoo page. Anyway... if you havent changed the wiring, then you will need to set the new programmer to the same as the old one (i.e. gravity fed jumper on the back of the programmer) or else it wont work. Just changing the jumper to fully pumped won't give you CH and HW independently. What you would have to do is fit a new cable from the programmer to the junction box if you can be bothered.