3 way valve and pump

[ballyclover]

HI

Yes i have bleed the pump both running and not running. i never bleed it while while they were heating up.

when i bleed it with it not running there is no air and the water comes out pretty quickly.

 

[ballyclover]

just been up to check, turned everything off and bleed the pump. its completely full.

the pipe coming of the valve which must supply the radiators is hot, as is the one going to the water cylinder,but radaitors are cold.

the pump is red hot too

 

[MANDATE]

Don't understand this! it's established now you do have a 3 port valve.
A 3 port works by having a HW only choice, a CH only choice and a combination of both, but you said you could not select CH only
For this to work correctly there has to be a programmer with 3 power supplies leaving it. Thats HW ON and CH ON and one from the HW OFF terminal. Now if thats not there, then theres nothing feeding the 'grey' when HW is off. In which case the valve wont go beyond mid position.
The only time it would do this is when HW is also on and been satisfied.
I still think its best to test the valve off the spindle so you can see whats happens but before doing so, you need to veryify if the 'grey wire ' going to the valve is live when both HW and CH are both off together. If live you must have power from HW OFF terminal. If not you've a wire missing.

 

[ballyclover]

to me this sounds like what is maybe happening, i have a 3 way valve which you are quite correct in the way it should operate, but as i dont have the option for heating only i the vavle only ever opens to half way.

i still think however that the pump is not working correctly

 

[D_Hailsham]

i have no idea what the gate valve is, sorry.

Do you have a valve on the flow from the Honeywell MPV to the HW cylinder or on the return from the cylinder?

What timer do you have?

i still think however that the pump is not working correctly

As the pump was new in January, it will still be under guarantee. Get it replaced.

 

[MANDATE]

You must also consider that with the valve in mid position the water from pump is shared, so the CH port is only half open, which will put some restriction on the flow to the radiators, for which you may be blaming the pump incorrectly.
Based on this, you need to get the valve sorted first.
Have you checked the grey wire in the terminal box for being live when both HW and CH are off.
If not live, then second question must be about the programmer and whether or not it has a HW OFF terminal.

 

[ballyclover]

the 3 way valve is marked a-ab-b

i assume when the spindle of the valve without the header is at ab then that allows water to both heating and water.

i have the valve in the b postion at the moment and the pipe to the heating is getting hot, i need to recheck the if the heating is getting hot in a while.

i dont feel comfotable checking the gray wire, there is a gray wire in the vavle head, but there is not one in the programmer

 

[D_Hailsham]

i have the valve in the b position at the moment and the pipe to the heating is getting hot, i need to recheck the if the heating is getting hot in a while.

How do you know it is is the B position?

The valve is stamped on the three pipe connections: AB is the input to the valve; A should be the output to the central heating; B should be the output to the hot water cylinder. If the connection marked B is going to the central heating, the valve is the wrong way round.

i don't feel comfortable checking the gray wire, there is a gray wire in the valve head, but there is not one in the programmer

The grey wire should go from the valve to the wiring centre (junction box). There won't be a grey wire connected to the programmer

What programmer do you have and which terminals are connected?

 

[ballyclover]

HI


sorry i was wrong about the postion which i think the valve is in.

it was switch to allow the central heating on, as the pipe work got hot and the valve to in the nearest radiator got hot, but thats as far as it went, didnt get any hotter, in fact went cold, even thought the pipe work from the 3 way valve is still red hot.

i need to check tomorrow what the wiring is like in the junction box from the valve

as for the programmer it is quite old, a danfoss 103, which is just an mechanical timer, with a button on the side, with either on,off or timer, the wiring again i have no idea off, but as the whole system worked ok a few weeks back i assume its ok.

i noticed that the pump has gone from making a noise, for which i assume means its working to a very quiet dull drune.
i have bought a new pump to try tomorrow as this is the cheapest component to replace.

i apprecaite all your help and know its difficult without really seeing it all first hand

All so, which way should the pump be installed, it has a flow arrow on but which way does this go, apprantly when the one was fitted in Jan, another plumber said it was the wrong way round.

The reason i cannot replace the pump which was fitted in Jnauary under
guarentee is that the plumber who did it told me he introduced a cleaner to the system and told the then owners to call him back in 24-48hrs to drain the system down and flush out the stuff he put in, he said they never did call him back and this stuff will still be in the system and has maybe clogged or damaged the pump.He told me he could not repair free of charge as his advice was ignored, he told me to drain the system my self which i did do, but what came out was clear,,,,phew

 

[MANDATE]

The flow arrow on the pump should go towards the motorised valve.
From your description of the timer, not having separate HW and CH switches, it looks like there will not be any wire from programmer to the 'grey' wire of valve.
The 'grey' wire of valve is supposed to be fed from two sources.
One is when HW is not on, ie it's OFF so a wire from the HW OFF terminal at programmer goes to the 'grey'. This is required to drive the valve from mid position onwards to CH. If HW was on, this wire would not be live so another way is used to make thr 'grey' live.
The second source starts at the cylinder stat. The cylinder stat is basically a two way switch. Power goes to the boiler, but when temperture is satisfied the the power is diverted from boiler to the 'grey'
In this situation the boiler stops momentarily and when the valve moves toward CH only the boiler starts up again. The difference being, the power to light it now comes from the orange wire of valve and not the cylinder stat.
As you have what appears to be an unsuitable programmer/timer, may mean the cylinder stat also an unsuitable type to run the system as it was designed to do.
It could be that the wiring has been somehow modified, to suit the existing programmer and cylinder stat.

 

[ballyclover]

thanks for all that, seem i have the boiler that jack built.

however that all said it was working fine before the last few weeks, and that still doesn't explain why the radiators come on but then go off, but the feed pipe from the valve is still hot.

could this not mean the pump is not strong enought o drive the water through

 

[ballyclover]

added a new pump today, i turned the thermasat on hotwater tank to 0 and all the radiators got hot, turned thermo back up to 55 and upstairs remind hot while down stairs got cool.

Turned boiler of completely for an hour and turned back on, no radiators got warm, repeated turning hotwater stat to 0, they got hot, turned back up to 55 and upstairs stayed hot.

I think the new pump has helped but something still wrong. I know now the valve is working as they got hot.

i think what is happening is even when the hot water is up op temp,if it drops bu just 1 the water is diverted back to the hot water so the radiators cannot get hot?

Anyway any further suggestions or ideas??

 

[MANDATE]

In the 'Y' plan system, you have to consider how the cylinder stat functions and how the room stat functions.
Cylinder stat. Wire from programmer goes to cylinder stat and from cylinder stat to boiler/pump. The stat has a third terminal, so when HW is satisfied the power is diverted to the third terminal and supplies one of the two sources of power to the 'grey' wire of valve. Without a live 'grey' motor cannot go beyond mid position.
Room stat. Wire from programmer goes to room stat and then joins the 'white' wire of valve.This 'white' goes to two microswitches and caters for (a) moving the valve to mid position (b) providing a modified voltage to hold valve at mid point (if grey is dead) (c) providing a output voltage on the 'orange' wire when HW has been satisfied or switched OFF.
When the room temperture is satisfied and valve is already in the CH position, the room stat just stops the supply out of the 'orange' wire.

In your case, it appears the programmer is not the correct type. The valve cannot go to the CH position. The cyinder stat is of an unknown type. The system works of a fashion and I can only think the wiring has been 'doctored'. The room stat can't be cutting off the supply through the 'orange', because it does not power it up in the first place.Maybe it's wired direct to boiler!
Also it's not clear if there are wires connected to the 'grey' and if there is then from where do they come.
To me the CH port is never fully open and I would think that is bound to have an adverse effect.
It would of interest to know how your system is wired.
I would suggest you consider changing the programmer and cylinder stat if necessary and wiring it so the valve works as it was designed to.
Sorry can't be more helpful.

 

[ballyclover]

yea, was thinking maybe the controller isnt quite correct, its something i need to investage further, maybe bite the bullet and get a plumber out to sort it

 

[D_Hailsham]

The Danfoss 103 is not suitable as it is only a single channel timer, intended for use with hybrid systems, i.e pumped heating and gravity hot water. The mid-position valve will never work properly while you have this timer.

The simplest solution is to install a two channel programmer which provides the following outputs: CH ON, HW ON and HW OFF. This would be used with your existing room thermostat If the HW thermostat only has two terminals, it will have to be replaced by one with three.

get a plumber out to sort it

Not the plumber who couldn't diagnose the fundamental fault with your system or the one who provided the b*st*rd*s*d system you have.