Valve/actuator funny noises!!!

[ste69]

Hi there, hope someone can clear up a problem for me. Since moving into our house last year, (its 8 years old) we have had sporadic problems with central heating. It's a Potterton/Honeywell system and occasionally fails to deliver water to radiators or sends it through when only hot water is required. Doing some digging around, I came across the actuator+valve (I think) in the airing cupboard making rather odd noises ( a bit like a stuck solenoid) The Hot water light would be on, but not the CH light even though both were called for at the control downstairs and the thermostat was up high enough to activate it. After about 5 minutes of strained pushing noises, the pump would suddenly work and water would be heard rushing off to the radiators. Problem solved until the thermostat was satisfied and then the problem would start over.

I should point out that without a bit of tapping on the actuator/valve from me, it would never get going.

After all that, my question is: Can the valve be fixed/freed up so it works without coaxing or do I need to get a replacement fitted?

Hope someone can help

Cheers.

 

[dadlfixit]

It could possibly be one of two things.
If its the type of diverter valve I think it is, it could be that you need to replace the valve cartridge. This is a sprung plunger inside a plastic sleave these just wear out and are simple to replace. To test it remove the the valve actuator and push the plunger in manually with the handle of a screwdriver. It should be a firm but smooth movement. If its not then replace it. If you leave it too long the internal workings of the valve actuator get damaged.
If you replace the cartridge and you still have the same problem then consider changing the actuator.

 

[MANDATE]

Seems to me to be the typical problem associated with a 3 port valve. CH only works with the HW but will not function alone. Valve is supposed to move to CH position and also operate a microswictch.
Either the motor is failing or the microswitch has failed. Take the head off the top of the valve and see if the quadrant moves the same amount between HW to mid point and mid point to CH positions. When at the CH only position check for voltage on the orange wire. no voltage proves the head is at fault. Also check the valve spindle for stiffness.
There are other posts dealing with this same problem.

 

[ste69]

Cheers both of you - at work at the moment but will have a look tonight. Is the actuator easy to remove from the valve? From your comments, it sounds as though something may just be seized up inside (hopefully) can you provide a link to a supplier for the sleeve or (if needed) the new actuator. Fingers crossed I won't need either of them eh?

Thanks again and I'll post again tonight with results!

 

[MANDATE]

If it's a potterton valve, the actuator can be removed easily. I think it was cross head screws to remove the head and torque screws to dismantle the head. I purchased a Myson Power Extra Head No ACT322 (that means 3 port 22mm pipes) from Plumb Centre about £38.
The problem turned out to be one of the microswitches which I have since rectified.

 

[ste69]

Ok then - update time.

No sign of plunger type things but it has a spindle and the quadrant thingy you mentioned.

I operated the sytem in all positions whilst the actuator was removed (didn't disassemble the unit tho - no torx screwdrivers)

Its "natural" position is for DHW only and this is flat (if you like). the DHW and CH position together is 45 degree and the CH only is 90 degree. (hope this makes sense)

As I set it to CH only, the motor tried to turn the quadrant through the 90 degrees required and basically struggled to do so and never got there. It made it past the "both on" position (45 degrees) but not all the way. As I then called the system for DHW also, the quadrant spun back smoothly to 45 degrees no problem and as i turned the CH off it returned to the flat position immediately. making a noise like a kid pushing a toy car with a friction motor in it.

As I said in my initial post the motor just tries and tries in short bursts but cannot seem to turn it to CH on. It makes the sound like an electric motor that is jammed (i can only liken it to our paper shredder when you put too much in and then it jams and burns itself out)

There is a lever that overrides but this only allows me to lock it in the CH and DHW together position.

Is it time for a new actuator????

PS the spindle that its trying to turn is free and can be turned between finger and thumb easily.

Thanks for all the help so far chaps!!!

 

[MANDATE]

Yes it all makes sense! Well it appears you have located the problem.
You have a choice. Either replacement actuator with five wires to connect cost just under £40 or a new motor which I think needs soldering in cost about £15. (plus security type torx screw driver bit to dismantle)

 

[ste69]

Brilliant - So I think a new actuator is probably the best way to go. Will it fit straight onto the spindle/valve i already have? and is the wiring pretty straight forward (I'm only a teacher!!!)

Am I looking for the 322 type? and if so, is plumb centre the best bet?

 

[MANDATE]

I don't think you stated the make or model of the 3 port valve. So have a look for model No, also check size of pipes as there is also a 328.ie 3 ports/pipes 28 mm diam.
The one I dealt with was a potterton boiler, but come to think about it I think the valve might have been a Honeywell V4073A, I'm not sure
The wiring is straight forward enough but don't just turn boiler to standby, make sure it is switched off and fuse removed.
There are only five wires to replace in the wiring terminal box.Best to make sketch with terminals numbered and see if you can identify and trace the wires to the valve and make a note of them.
The wires relating to the valve are 'white' 'grey' 'orange' 'blue' and 'green/yellow'.
There will be a few blue wires for these are the neutrals. There will also be a few 'green/yellow' wires for these are the earth wires.
I did consider using a terminal strip fitted within a wall mounted box so I could cut the existing cable and match it with the new cable 'colour' for 'colour'
I wonder what subject you teach? Not electronics then!