HONEYWELL V4043 2-PORT MV:

[RONCHAM]

Hi - this should be easy (but not for me!). I've got a Honeywell V4043 2-port MV with the external manual lever. HW tees off before this so is either on alone or when CH is on. At present, only upstairs rads are heating up - I've tried bleeding all rads. My question is ... can the manual lever on MV be seen to move across when programmer switches CH on?? I'm assuming it must but I've never bothered to watch before! Also, any suggestions on the cold rads downstairs (the pump and MV are in the upstairs airing cupboard).
Any advice gratefully received.

 

[davebgas]

The lever is to move the valve from 'auto' to manual and is only used for filling/venting.
It wont move when the valve motors, likewise if you force it open it wont make the microswitch....

 

[seco services]

what speeds the pump on?
how many rads downstairs ? are they all on one drop down from upstairs rads ?

 

[RONCHAM]

That was a quick response!! - thanks. Pump is by Circulating Pumps Ltd - 3-speed and it's on position II. 4 rads downstairs plus 2 small ones in conservatory all on one drop down. Strangely one of 2 drop-downs in a downstairs cupboard (flow?) is quite hot but other is cold (as are rads downstairs!!). Nothing has changed to my knowledge since last operational. Saw similar question (June 2009) where guy said hook valve open manually for testing purposes and switch on CH at programmer - lever should then move freely if MV is ok??

 

[seco services]

mv's ok if upstairs is getting hot.

shut upstairs rads and leave downstairs on.
then turn pump up to 3.

let us know what happens.

 

[RONCHAM]

Trying that as we speak and found something perhaps revealing? When I advance CH only on programmer, pump and boiler do not come on. Have had to advance HW too then pump and boiler come on. Lever on MV is floppy compared to stiffness when CH/HW off. Pipe downstream of MV is hot as is one of 2 main drop-pipes downstairs. Only one rad d/stairs appears to be warming up (slowly) and is the one nearest to drop-pipes. Normally rads warm up fairly quickly, if not rooms.

 

[seco services]

Trying that as we speak and found something perhaps revealing? When I advance CH only on programmer, pump and boiler do not come on.

does it work ok if on timed, ie in the morning etc ?

Lever on MV is floppy compared to stiffness when CH/HW off.

it willbe if valves open.

Pipe downstream of MV is hot as is one of 2 main drop-pipes downstairs. Only one rad d/stairs appears to be warming up (slowly) and is the one nearest to drop-pipes. Normally rads warm up fairly quickly, if not rooms.

give it time if you have only just started it.
just check they are open.
long as that boiler keeps running its doing something.

 

[muggles]

When I advance CH only on programmer, pump and boiler do not come on.

Do you have a room thermostat (small box on a wall with a temperature range on it)? If that is satisfied, IE up to temperature, then the boiler will not fire even when you turn the programmer on.

 

[RONCHAM]

Sorry for delayed response, will have to get back to you re. whether ok on timed. CH and HW are programmed with same on/off times - although in summer, only HW was programmed on/off. In the past CH advance on programmer would switch things on if occasionally needed.

There's no room stat, all rads have got TRVs - even HW cylinder has TRV with a copper wire sensor off it to a block clamped on cylinder.

There's only 1 MV as mentioned that opens/closes CH circuit. I notice this morning (after 1 hour on) downstairs rad mentioned before and another, both adjacent to drop-pipes, are gradually warming up - other 2 (bigger) rads are cold. Could there be almighty air-lock?

Can the MV open but still fail to turn on pump & boiler? - are these independent operations?? I hear mention of microswitches in relation to MVs. Wondered if one function can work but other fails?

If I change motor on MV, does valve have to be in any particular position before I remove old motor? - why are there more wires than you can comfortably curl back inside casing!!

 

[RONCHAM]

Hi Seco Services - in answer to your query, if I programme CH only to come on, it does NOT!! Not sure if this is just something I hadn't noticed until now and perhaps not related to problem anyway. Lot of pipes in upstairs airing cupboard are hot in vicinity of pump - inlet to HW tank and downstream of MV when open - but not sure where all the heat is going??

With system on for ages (HW only) HW barely warmed up even though tank inlet hot and outlet cold - this is 15mm inlet, thought it was often 22mm?? Couple of d/stairs rads started warming up but not 2 biggest in front/back rooms. Only thing I haven't tried is to open MV manually. But if lever goes limp and pipe d/stream quite hot, doesn't that mean it's opened ok?? If pump/boiler working, is only other possibility an air-lock?? How would I check for this in HW circuit?? - seems almost it can't arise. Vertical pipe from top of HW stayed cold (not surprising as HW hardly seemed to heat up). There's a tee off this to a towel-rail, also cold now.

Would appreciate any more suggestions from anybody - seems very very strange behaviour??

 

[seco services]

have you any pics or layout drawing of the system ?

 

[RONCHAM]

It's a weird and wacky system (but I understand a fairly common old arrangement especially the single MV) but it has worked very well until now. Not sure if visible in photo but green verdigris on joint at inlet to MV is not new.

 

[RONCHAM]

I've added a photo to album I've just created and thought I'd attached it to my previous reply?? If not, how do I do that?? - haven't posted photos before. Album is called Ron's Photos and is visible to members.

 

[seco services]

sounds weird. is the hw gravity or pumped ?
then you say all rads have trv's has it got a bypass ? as where does the water go when all trv's closed ?

 

[RONCHAM]

HW is pumped and always on with CH as tee-off to HW tank is upstream of MV to central heating. I thought bathroom rad was by-pass but not now so certain (it's also got a TRV which I leave on max). Inlet to HW tank is 15mm and that's got a tee-off which then drops down under floorboards. This is pipe I assumed goes to bathroom rad but difficult to follow it.

Can you see photo?? Think you can becos I've at last spotted info on attaching a photo to my post!!

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