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[tickmike]

Last summer I got around to changing my 11 central heating zone valves for downstairs as the old ones had been in for 20 plus years and we were having problems with them .
I bought 11 more from a well known company (via there distributors).

Out of those 11 new valves Five now have failed  , the motors seem to go open circuit

There is no smell of burning from the motors, no marks they just look normal.
The coil resistance is infinity !. compared with about 100 ohms for the good ones.

Each valve is controlled by a zone thermostat and the feed is taken off the boiler and is the Same feed to the two pumps and is under the control of the time switch.

We have no problems with any other electrical equipment in the house.
The mains supply is within the supply spec.

Has Anyone Got Any Idea Whats going Off With These Valves Failing as it got me baffled. 

It's also got the manufactures baffled, they have sent me 11 more FOC (£500 plus ) 

[oldfogy]

Sorry I can't help, but must say I've never heard of those types of valves on a CH system.

Hope someone can enlighten you.

[Ronski]

Perhaps a bad batch, or perhaps they get too hot. I bet the twenty year old ones were better made.

I have a similar set up, each room has a Heatmiser thermostat with integral timer, I have a bank of six zone valves in the upstairs airing cupboard and another bank of 5 downstairs. One thing I remember (IIRC) when I installed them was their maximum operating temperature was 50 degree's.

I've attached some pictures, the first one shows the zone valves in the airing cupboard, before they were wired in. This now has a slatted shelf above to allow the heat to rise.  The next shows the downstairs valves, this has a lid with plenty of ventilation holes around the side. The last one shows the wiring connections for the 240v side of things for the upstairs zone valves (black cables), and connections to the thermostats (white cables). The thermostats are all networked back to the PC, but the software was pretty poor really so I don't use it, one day I may write my own program to control them all from the server.

Edit: I think you can now get zone valves which replace the valve on the radiator, which would of simplified things for me a lot.

[oldfogy]

Interesting and many thanks for the pictures, my only one concern would be with the new plastic push-fit connectors and what I believe is their lifespan of only about 15 years, pus I have heard people saying they have started to fail on their systems.
(sorry no confirmation link for that, just something I read some time ago)

[Ronski]

Yes I was worried about them too, but it wasn't practical (time wise) to try and get copper in, I hope that decision doesn't come back to haunt me in the future. The majority of them can be changed, but there are some which would prove to be very difficult to get to now.

[tickmike]

Looking at your photo's 'Games room' and 'Hall' they are the same valves as I'm using 'Hortsmann ' type F222 and the replacements I have been sent are like your other ones type Z222.
I have 'Crimped' all my connections.
As mine supply the under-floor heating and some wall heating it is only run at 40C to 70C, so I would not think it is a temperature problem as they are made for 99C, just faulty batch.

[Ronski]

I bought mine in stages, first batch in November 2005 from Screwfix £32 each, the others from BES a few years later for £26 each. As you can see the games room is still not connected, been using it as my workshop whilst I do the rest of the house, hopefully though 2014 will be the year it becomes the cinema room 

I've just checked the specs on Hortsmann's website and it does state maximum ambient temperature of 50 degrees, maximum fluid temperature of 88 degrees for the Z222. It's the same for the F222 as well. Link to documents

Just found these reviews on Screwfix for the F222, doesn't look good but perhaps they have simply been getting too hot.

[tickmike]

Thanks for the links, gosh I'm not the only one having problems looking at the reviews.
re 'ambient temperature of 50 degrees' I have to check this as one set is in the airing cupboard and the other set is in enclosed wooden cabinet 
I had the last batch from BES 
It's an odd design, as I can see the synchronous motor is powered and moves the valve across against a strong spring, then at the end of it's travel the motor 'stalls' against the spring force, when the mains power is taken off the motor the sring closes the valve.
I will try to find time to do some tests on them.

[sheddyian]

Back in the Summer, I found that my hot water was no longer getting hot, and after a bit of fault finding, found that although the hot water zone valve was opening correctly, it wasn't operating it's internal switch to start the pump and light the boiler, so in effect nothing was happening and the water stayed cold.

It was a Honeywell valve, and when I took it apart to have a look at it, I found it was made in 1976. So had probably been working for around 36 - 37 years in a hot airing cupboard.

I looked at alternatives, then spoke to a plumber friend who advised me to get another Honeywell as he so rarely had faults with them.

Naturally the Honeywells are the most expensive of the valves I looked at.

Regardless of the make, they shouldn't be failing that quickly though, but I thought I'd just mention my experience.

Ian

ps interesting to compare the insides of the original 1976 and the new Honeywell zone valves - better insulation & electrical connections and ability to remove the mechanicals without letting any water out on the new one, but otherwise - identical.  I suppose a good design doesn't need that much tweaking!

[tickmike]

Update ... I got some of these motors.
http://www.ebay.co.uk/itm/181071311813?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649
Fitted them, but they get very hot, I used a Mercury thermometer and it went off scale at 50 degrees plus (I have a electronic thermocouple temperature device I will have to find it out again, that can read high temperatures. )
The valves I have in the airing cupboard I have modded the covers by drilling 16 off x 8mm holes  (4 each side ) in the blue covers to improve ventilation and also pulled off the Aluminium motor cover.
Also modded the one's that are enclosed by leaving off the blue covers of the valves and again also took off the motor Aluminium covers, I also looking into improving the ventilation in that cupboard by fitting some grills.