dodgy zone valve? ...i hope

jakeuk · 21 Oct 2006

Hi guys...ive got a problem which is mostly covered by 1 of your FAQ's

but with maybe a tiny twist???

ive got a gloworm ultimate 60 bf.

a grundfos 3speed pump

a honeywell sundial y plan 3 position diverter valve

nine small rads.

plenty of hot water & stone cold rads...the systems been dodgy since we moved in this april..ie.turn the hot water only on.. & upstairs rads would get warm,not hot at same time
though at that time, the central heating did work both in conjunction with & independantly of hot water.

ive tried the manual overide on the zone valve which does induce the boiler to kick in & rads get hot but only when i hold the switch/lever right up to the top of the casing..the hook position is not far enough & i dont think it will stay on the hook even if it was high enough

what i need to know if possible & before i buy a new motor or whole valve is, is there anything else other than a broken motor that might cause these symptoms?

i hope this is enough info & thanks in advance

BTW fantastic forum

croydoncorgi · 21 Oct 2006

Both types of Honeywell motorised valve (3-port, zone valve) are SPECIFICALLY designed NOT to switch on the boiler when manually operated and latched.

If the valve is moving freely manually but does not move at all by itself, chances are a new motor is all you need (£10 - £15). Switch everything off, remove the cover of the valve, switch back on, set for heating. Then watch for signs of movement, then check for live on the motor leads. If one is live, get a new motor

Be careful - mains voltage present on several wires.

jakeuk · 21 Oct 2006

Wow..thanks for quick response croydoncorgi dont have the tech ability for electric faultfinding myself but there is no signs of movement on the switch when heating is turned on...i dont know if this is relevant but i find it really stiff to get it it into the top (heating)position is this rigidity normal on a good valve or indicative of a goner?

ps ..was quoted £21 buy the larger high st plumbing chain for the motor

ChrisR · 21 Oct 2006

Stiff no, but quite a strong spring. It should whirr shut again in half a second or so. If you open it pushing really hard it'll go on further than you can push it slowly, and momentarily "make" the switch in there which turns the boiler on.

croydoncorgi · 21 Oct 2006

Unusual for valve to stick only at end of travel. When heating only is selected, the ball inside the valve is supposed to move 'as far as possible' - hopefully so that it closes fully against the 'B' port of the valve. In un-energised state, the ball should be covering the 'A' (heating)port. (Boiler flow connected to AB.)

If you latch the valve manually, this positions the ball mid-way between the ports, so both are open. In the latched state, whether the boiler fires or not depends only on the hot water control: if the programmer is selecting hot water and the thermostat on the cylinder is calling for heat, the boiler and pump will run - and heat will therefore go to cylinder AND rads.

If rads only get 'warm' instead of hot, you've probably got two problems.

jakeuk · 21 Oct 2006

guys i really honestly appreciate & need all your help & input..but ive been up nearly 24 hours now(night shift worker) and im absolutely knackered to the point where i cant take anymore info onboard..can i throw myself on your mercy and ask to resume your help another time..gonna fit a new synch motor asap & go from there.....big SORRY & bigger THANKS..hope to pick your brains again tomorrow

jakeuk · 22 Oct 2006

croydoncorgi said:
If rads only get 'warm' instead of hot, you've probably got two problems.

ch thermostat is it?

its one of these allen martin ET things ..dont know how common they are or how reliable but i had a look inside yesterday & all i could fathom was that the temperature setting pins/swithes are all in the max position

i tried the "get you warm" Tip in the FAQ section..turned the hot water stat up to 70 & the boiler heat control down low but still no water to rads

2face · 22 Oct 2006

i had this probem just the other day .. there was a bypas fitted .. and open full which starved the heating of all the heat .. i closed the bypass (that is not needed on a yplan )and all was good .. also there was a massive air build up of which the bypass open did not help either.

other causes i have possible:

sludge build ups in the rads . ?
air?
incorrect pipework in cupboard?
siezed y plan not fully opening ?
tired pump.?

does this help at all or confuse matters ...

jakeuk · 22 Oct 2006

Hi 2face...no m8 it dos'nt confuse matters & if i knew a bit more about which pipe goes where it would probably help..but i aint got a clue i'm embarrased to admit..

i did drain the heating right down yesterday and to my surprise there was no sludge ..a fair ammount of discoloured guiness like water but no sludge

i tested the pump on all 3 settings and there was very distinct audible change so i'm guessing that the pump is at least ok

i turned the hot water on at control panel this morning (but not the heating) & the rads upstairs are all working

jakeuk · 22 Oct 2006

i managed to get the manual overide to stay in the latched position & now the whole house is hot...is it safe to keep running the system in this state untill tomorrow when i can buy & fit the new motor?

ChrisR · 22 Oct 2006

Sure.
It'll go off when the HW gets up to temp though, so if you turn the HW stat right UP and the boiler stat to minimum, the HW will never make it but your rads will stay warm while it's trying.

jakeuk · 22 Oct 2006

thanks again guys..fingers crossed that new motor will sort it out tomorrow

croydoncorgi · 22 Oct 2006

'Guiness-like' water rings alarm bells.

Things to remember about water in CH systems:

- Brown sludge and / or brown coloured water means LOTS of air in the system, getting in from somewhere, and A VERY BAD THING. The system needs fixing urgently before major blockages occur.

- BLACK sludge (which actually is virtually insoluble) means less air (but still some) getting in and is still a VERY BAD THING because it will still ultimately block your rads and shorter-term block the secondary heat exchanger and internal pipework of your boiler (especially if it's a combi).

- ALL systems should have chemical corrosion inhibitor added and kept at the right concentration. If you drain the system (or part of it) you need to top up the inhibitor when you refill. It's a COMPLETE WASTE OF TIME adding inhibitor to a system that's full of sludge and / or has serious aeration problems. You will be in a Fool's Paradise because the effectiveness of the inhibitor will last only a few weeks at most.

jakeuk · 23 Oct 2006

first off...big thankyou guys.. new motor in & system working again

guess who dropped one of the fixing screws down the back of the tank

regards the water..i will buy some inhibitor tomorrow & give it another flush...there are no apparent leaks anywhere unless theres any under floor??...but the old guy who sold us the house said 1 of the rads needed bleeding on a regular basis..but i do know the house was extended & i'm guessing a good while after the initial instalation...the 2 extention rads are furthest away from the pump and when all the rads are on full the extention takes ages to heat up so a bit of balancing needed there...i also know at least 1 of the thermostatic valves is kaput so all in all, a bit of time & money needs investing and i may be back for some more tips & advice if thats ok.your help really is appreciated so once again big THANKS....

John..

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dodgy zone valve? ...i hope

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