CH and HW dependence after repairs

[nyamago]

Thanks for this advice, valuable as usual. I am trying to do this, but...

The genius, who built our system has mounted the valve vertically, with its top facing a nearby wall (just an inch from it), and 2 pipes also very near - mission impossible to dismantle powerhead to gain access to the valve spindle

Managed to remove the tin cover, but still fighting with those 2 screws, and I'm not winning so far... There's no room from the screw heads to the wall for even the smallest screwdriver (and they require a slightly larger/tougher one).

Improvising some 'tool' solutions and will report a bit later -

= = = Edit: 1.5 hours later - = = =

Hurrah! Actuator is finally off (how I wish I knew who installed it!)

The spindle was stuck, indeed. In a position where the flats on it are perpendicular to the A-B pipes.

A minor effort using pliers made it turn a little - but really little (about 10 degrees, mostly clock-wise from this perpendicular position, only 1-2 degrees anti-clock-wise).

I don't dare force it for now, so I sprayed some WD40 and will try again.

[matt1e]

D_Hailsham wrote:

nyamago wrote: CH OFF (Room stat to 'Min' and Programmer w CH 'Off') HW ON (Cylinder stat On at 70 deg, Programmer w HW 'On') 3p Valve on 'Auto', both A and B pipes feel equally hot Boiler and pump running The valve is sticking in mid position. Remove the actuator (box on top) and you will see the valve spindle. This should turn easily but about a quarter turn or less.If it is hard to turn, a little WD40 may free it. If that does not work you will have to change the whole valve Quote: re. Flamingo over-run: when cylinder stat cuts demand, the pump keeps working for a little longer. I haven't clocked it, but it's not more than a couple of minutes. Not sure if this can have anything to do with the above problem - probably not. That's definitely pump overrun; and it's nothing to do with your problem.

I'll second that
from your latest post it definately sounds as though the valve is sticking mid- position and as dave has said{think thats his name} the pump is nothing to do with your problem its controlled by the boiler- ignore what it is doing for now
the valve stuck in mid position would definatly give the problems you are having
but since all your problems happened just after your upgrade there is still a possibility of a wiring issue

multi meter would be a big help

matt

[matt1e]

oops posted before I saw the latest update|

well we are getting there, good luck with the wd40 but the valves are not that expensive anyway in case that doesnt work
a quick point though the spindle normally doesn't turn as much as you expect it to

matt

[nyamago]

I reached the full turning capacity of the valve, it really isn'tmuch - definitely less than 1/8 turn (45 degrees) - more like 20-30 degrees, then you feel a resistence like 'metal knocking on metal' and you know it won't go further.

In the end I didn't need pliers and could turn it all the way (in that range) with my fingers. So far so good.

PROBLEM is, it still does what it did before: keeps both A and B pipes hot, no matter what position it is left in. Since I assumed that somewhere in the middle of this movement is the 'both' (A+B) position, I tried for an hour each of the extremes - perpendicular to the pipes (nearly), and at the max angle possible.

In both extreme positions it kept bot A and B pipes very hot - as far from it as the cupboard space allows. I remember, before theproblems started, in CH OFF position that pipe was getting cold (room temperature) at 30 cm from the valve, where it enters the floor. Now it's very hot all the way, all the time. (The HW pipe never gets that cold, because in OFF position it is getting some heat from the already hot water inside the cyllinder).

I think this indicates that the valve itself is gone, and needs replacement.

Not sure if this adds anything to the picture, but another observation: as the spindle turns and passes from one position to the other, there is a noise through the pipes like a quick burst of flow, or like the release of bubbles.

In the meantime I played a bit with the actuator head off the valve: cleaned and moved it a bit, lubed very lightly (with just WD40 on pivot points) and now it seems to be mechanically OK. The lever does return now, from Manual to Auto position, under the spring action - further proof that before it was held by the stuck valve.

I don't know if Honeywell sell the valve part separate from the actuator, but this head shows signs of wear and, even if it works, a complete assembly - valve with actuator is what I'll be ordering.

I will still do all the electrical tests this weekend, just for peace of mind - but my (peace-less) mind is already on the next task: replacing the valve. May be a 5-minute 'piece of cake' for you pro-s out there, but a mammoth task for someone who doesn't know which end of the spanner... ... ..

to be continued

[D_Hailsham]

nyamago wrote:

A minor effort using pliers made it turn a little - but really little (about 10 degrees, mostly clock-wise from this perpendicular position, only 1-2 degrees anti-clock-wise).

The total movement will be about 20 degrees.

The stiffness is caused by the swelling of the 'O' ring which seals the shaft, preventing water leaking past. Honeywell sell a replacement ball and 'O' ring kit for this valve. The part no is 272752A/U and cost about £5. You should be able to change the part by bunging the feed and vent pipes of the small tank in the roof, this will mean you don't have to drain down.

[D_Hailsham]

nyamago wrote:

I reached the full turning capacity of the valve, it really isn'tmuch - definitely less than 1/8 turn (45 degrees) - more like 20-30 degrees, then you feel a resistence like 'metal knocking on metal' and you know it won't go further.

Sounds as if the rubber ball has disintegrated. This can be replaced - see my last post.

It will be difficult to test the actuator if the ball is missing/broken as the tests rely on the ball blocking the A and B exits from the valve.

If you have a meter, you can do basic electrical tests on the actuator.

Disconnect the orange wire.
Turn CH OFF, HW ON and HW stat up
Boiler will run
Voltages on White, Grey and Orange should be 0V
Turn CH ON and CH stat up
Motor should run to mid position and boiler continue to run
Voltage on White should be 240V
Voltage on Grey and Orange should be 0V
Turn cylinder stat down to min.
Motor should run and valve move to CH only
Boiler should stop (this is because the orange is disconnected)
Voltage on White, Grey and Orange should be 240V
Turn HW OFF
Voltage on White, Grey and Orange should be 240V

If the voltages check out, the actuator is OK.