2 Heating questions please

[poolebybirth]

Hi all...

I have 2 heating problems (queries) that I would like your advice on if I may.

1) The heating is taking a little longer now to warm up. The cold feed pipe from the feed cistern is not blocked as I have checked this and drained water and it re-fills.

Could it be scale/sludge built up over time in the pipework ? After reading posts and info on this site I believe that a lot of these "sludge build ups happen in the Tee junction where the cold feed and vent join the primary/heating circuit.

Can I use Sentinel X400 to break up this scale/sludge and remove it a week later? Or will I need to replace pipework?

My second point:

2) the diverter valve we have (Honeywell silver casing) is acting weird! :

when hot water and heating are on it is fine, but when we override the h/w to be on only the heating doesn't go off!

is this a stuck valve? it seems obvious probably but is quite puzzling, especially as the heating and h/w both work fine (and on their own) when only programmed to be on one at a time!

 

[seco services]

both your problems could be both down to sludge in the system if not in the feed/vent pipe but in the whole system rads etc.

your mot valve could be jammed in mid position so when only hw on it is also passing to heating. even if the heating is off and hw on.

do you find any rads hot at the top and cold at bottom ?

 

[poolebybirth]

hi seco-

when i have heating on only or hot water on only it is fine, both do not come on then, it's very strange i know!

also in general the heating takes longer to heat up and yes i suppose they do feel slightly cooler at the bottom. but when i bleed them water comes out: this is another reason why i knew it was also not a blocked cold feed.

 

[seco services]

first problem i would put down to sludge and yes you can use x 400.
second problem. you say both are ok when calling for heat / hw.
but if you turn the heating off at programmer so only hw on the heating doesn't go off ?

 

[poolebybirth]

when heating is calling only (on a motorised alve-honeywell v407) the white wire will be live (from the room stat making) and then the motorised alve motor moves across and makes the orange wire live (which is also connected to the same terminal box as the live for the pump and boiler). this is right isn't it? i might have a check with my multimeter and see why the valve isn't working properley..

 

[poolebybirth]

first problem i would put down to sludge and yes you can use x 400.
second problem. you say both are ok when calling for heat / hw.
but if you turn the heating off at programmer so only hw on the heating doesn't go off ?

yes that is correct. basically when both are on it is fine, then when i push the ovveride on the programmer to just hot water on (so heating is switched off) they both still stay on)! ... why's this?

 

[seco services]

yes thats right. and when stat turned down or programmer off for heating you should not have power at the white

 

[poolebybirth]

yes thats right. and when stat turned down or programmer off for heating you should not have power at the white

and likewise when hot water and heating on the grey wire is also live (as the valve moves into mid position) so they micro switches inside it put power to grey as well..

 

[seco services]

grey will only become live when hw satisfied by cylinder stat or programmer hw off

 

[seco services]

sounds like programmer still giving live when only hw on.
check if you loose power on the white when this happens.

 

[poolebybirth]

grey will only become live when hw satisfied by cylinder stat or programmer hw off

sorry, grey white and orange live mean heating only, white and orange live mean hot water and heating, orange live means hot water only. this is correct i think!

 

[poolebybirth]

sounds like programmer still giving live when only hw on.
check if you loose power on the white when this happens.

seco-thing is when hot water is on only (on its own) it is fine and no heating is on (sound white is not live obviously).

so maybe the valve isn't returning properley to its rest position after having both h.w and heating on together? maybe the spring is knackered or some crud has got into it over the years ??

 

[seco services]

orange will become live when one of them is calling for heat to give power to boiler/pump.

white wire only live - valve in mid position for hw/heating.
white/ grey live - heating only 230v at orange. hw port shut.
grey live - valve held in last position 100v appox on orange.

 

[poolebybirth]

seco thanks for clearing that up - also is this true: when programmer time switches off power (eg at 9am), the valve returns to it's rest position (usually h/w port open) and )o voltage to any of the wires (obviously)! :_

 

[seco services]

when the valve shuts the heating port it will be in its relaxed position.
may have crud blocking the port from shutting fully.

no power to valve will be in rest position yes