Radiators coming on with HW

[nobody]

Hi,

We have found that some of the radiators are coming on when only the HW is turned on. Also sometimes the pump and boiler contine to run when nothing is on.

We had our old oil boiler replaced with an Ideal classic ff1200 gas boiler some time ago, but only recently realized that the rads on the top floor are on with the hot water. I lifted a floorboard on the middle floor and found that all the pipes seemed to be hot, not just the ones to the hot water tank.

There is a pump which sems to push the return into the PR connector on the boiler. Above the pump (on the other side to the boiler) is a junction and a pair of 2port zone valves.

The Boiler connection PF (I assume flow) connection comes out of the boiler, forks and both parts go up into the ceiling.

The zone valves are drayton ZA5s. My first thought was that a zone valve had failed so I bought a replacement. Looking at the replacement though it implies that the ones fitted are upside down.
The replacement has an A and B marked on the body (the existing ones are up against the wall so I cant see any direction marking) and the instructions say flow should go into the A end and out of the B end.
sort of like this where --+== represents the pipe forking into 2 and then going into the valves and the { and } represent what I think is the direction of flow (on the basis that if I turn on the heating thats the order in which pipes get hot)

[code:1]
floor. . . . . . . . . . . . . . . . . . . . . . ceiling

BOILER PR--+
|
+-----}----+
|
+---{-PUMP-{--+=={=A Zone Valves B=={==

BOILER PF--}---+===}====

[/code:1]

Its a bit more complex than that because the pipes cross over each other as they go out into the ceiling.
(Isnt it a pain trying to draw in ascii?)

The pump is a Grundfoss and I assume has a direction marking on the body but its in the corner and I cant see anything. If it helps, the text on the front of the pump is upside down (as is the text on the front of the zone valves.)

So questions for m'learned experts

A quick web search for layouts gives me that this is S-Plan. And the diagrams all seem to show that the flow should be out of the boiler, through the pump, then the valves and then off to the rads/hot water tank. Does that make sense?

What would be my best approach to sort this out?

Should the pump push water into the boiler or suck it out ?

And I assume that the valves should be on the flow side not the return side ?


As an extra thought - Could they have cross connected the hot water and CH pipes - how would I tell other than lifting carpets and floors to check where pipes go.

I hope thats given a clear picture of the problem.

Thanks for reading this far, you've earned a virtual beer token.

 

[Nige F]

Hi,

We have boiler. zone valves an A and B marked on the body complex than that because the pipes cross over each other as they go out into the

What would be my best approach to sort this out?



I hope thats given a clear picture of the problem.

Thanks for reading this far, you've earned a virtual beer token.

Can you post some pictures?...........step 2 call a heating engineer out[/quote]

 

[nobody]

Hi Nige,

Pics are tricky because of the angle and access but here we go

This is the top of the boiler - connector on left is marked PR so I assume return. On the right is market PF - Flow? The PF comes up in front of the PR and splits into two both of which go off through the ceiling. There are a further two pipes coming down from the ceiling just off to the right hand side which go to the zone valves

Next bit down - we have the return running down to the bottom of the boiler, and the two pipes going through the zone valves. a 15mm pipe comes out of the ch pipe and goes off to a rad in this room.

And at the bottom, the rad pipe, the return which loops round to the pump (thats just a drain point on the bottom) and then splits before the zone valves

Hmm - off to play with how to show images...

 

[nobody]

OK - how do images work I have the image url between [ img ] and [ /img ] - without the spaces - but I cant see the images. If I right click and view image I get it though. What have I done wrong ?

 

[Nige F]

you`re doing better than me I haven`t even got a digital camera.

 

[nobody]

sorted!

OK. As a general question, should the pump be pushing water into the boiler return or sucking it out of the flow ?

And should the zone valves be on the flow (which is what all the diagrams show) or the return (which is where they are on mine)?

If I turn the pump around and swap the boiler flow and return connections then I will have something that matches all the diagrams I have seen. The boiler flow out -> pump -> zone valves (which will then be the correct way around. Is there anything I would need to check if I do this. We have a vented cylinder btw - I wouldnt touch the system if it was pressurised. And this is a standard one - not combi not condensing.

Otherwise I need to at least turn around the zone valves so they are the correct way around for the flow direction.

what do you think ?

 

[Agile]

The pump can be on the flow or return. Usually on the flow nowadays!

The motor valves are usually after the pump but can also be on the return.

The way to see if the boiler is correctly connected into your system is to see if the flow is hotter than the return when its firing.

It sounds as if your CH motor valve is leaking. You could try taking off the head and see if the shaft can turn it off fully.

Tony

 

[ChrisR]

I can't entirely work out what goes where from the pics, but he flow from the boiler IS on the right and you can't pump the water IN there.
The pump can be on the return, and so can the zone valves, but they must be the right way round or they'll "let by".

The valves in your pics are oriented such that water should be going UP through them. So it seems they're backwards if the water is going down to the pump then the boiler.
Can't tell from the pump pic (the head fits on 4 ways and makes no difference) - there is an arrow on each side of the base of the pump. If you can't find the arrow, the bulbous part of the base is connected to the pump inlet and the thin metal rib the output.


Pumps on the return can sometimes lead to problems, with pumping over the vent, ingress of air etc but if you don't have those problems you can leave the flow as it is
Looks like you'll have to turn the valves round though.

 

[nobody]

Cheers Tony and Chris,

the flow is hotter than the return so thats one thing that is correct.

I'm used to the fact that nothing in this house is done in the 'normal' or 'conventional' way.

I'll go ahead and replace the zone valves then. The ones that are on are much stiffer than the new one I bought. Cant turn them by hand, need to use pliers.

thanks

Mark

 

[bishbosh]

nobody:

that sounds like my house, all the previous occupants mucked up their DIY and nothing was done 'properly'

Did you manage to get your CH sorted out, since I have the same problem and would like to pick your brains if you fixed it.