Siemens 3 Way Valve Faults

[dave1510]

Hi,

My 5 year old house (built by a major company) has a "conventional" hot water/heating system:

Gas Boiler (Potterton?)

Siemens programmer

Pre insulated Hot water Tank (in airing cupboard)

Siemens DVA3 actuator

Siemens 22mm 3 port Valve.

Inhibitor in system.

The problems I have had from my first winter have been the same.

When working correctly, the water and heating work independently of each other.

How it's programmed:

Water on at 07:00 - off at 22:30 7 days a week.

Heating in Manual - if required use +1hr/+2hr/+3hr and then the heating should turn off, the programmer light should go out, and the radiators cool down.

What happens when the system is faulting (this IS intermittent)

Water (on at the time)

select +1 hr, heating comes on, programmer lamp for CH lights, programmer shows CH+1hr, Radiators get hot.

after 1 hour - CH lamp goes out, programmer show CH = off, Radiators remain hot, not cooling down.

FIX = switch WATER to OFF, wait 30 seconds, switch Water back on, Water starts, Rads remain cool.

I have had to date 2 programmers, 3 actuators, and 4 3 way valve bodies.

My thoughts?

In Feb 2012, I had a radiator moved, and the plumber drained down the system to do this, and at the same time replaced the 3 way valve body. He showed me the valve, and told me the design was a bit suspect, and the "port" was passing. The system worked well throughout the rest of 2012, and all 2013 - up to now, when I am starting to want to use the heating. It is now starting to show the usual symptoms of failure as above.

Ideas?

I have read on here about 3 port valves, and the consensus is they are "not good".

Is it possible to remove the 3 port valve, and replace it with 2 x 2 port valves? There are 5 cables from the DVA3 - Blue, white, grey, orange, and earth.

I know I will have to replace the one unit, with 2 separate units, but there is space to do this, and I am hoping that the cost will be covered by me not having to get the 3 way replaced every couple of years.

I have - in the past - tested the operation of the 3 way valve, and actuator  independently. I even have a spare DVA3 actuator. I am reasonably convinced the 3 way valve is to blame.

Any advice would be gratefully received.

Thanks

Dave1510

 

[steptoe]

ah, siemens, as much as they are good quality stuff, I have found there motorised valves to be, in a word, rubbish,

I would say a sticking valve,

change it for a honeywell,

any of these that my 'plumber friend' sends me to I dont touch until he changes them to honeywell,

I have come across far far more bad siemens valves than all the other makes together.

just my experience tho.

 

[Sidewinder]

FWIW,

I've just changed my supplier of PRV's from Caleffi to Honeywell.

The Honeywell valves seem much superior, more compact, nicer looking, and cheaper!

Neither are Siemens though!

 

[ProDave]

Just to add I have a similar problem with my Danfoss valves.

So the consensus is Honeywell are the best, I'll remember that in the next house.

It's a PITA that to change a faulty valve, you have to drain the system. Again, my next house will have isolating valves either side of any motorised valve, like you do with a pump.

 

[SLIPSHOD & SLAPDASH]

http://www.youtube.com/watch?v=Yyn_fBEH90U&feature=player_embedded#t=11

 

[dave1510]

OK thanks for the answers, it seems I do need to do a bit or work.

Can I replace a Siemens with a Honeywell?

Is this better than replacing a 3 port with 2 x 2 ports? (Less work obviously)

I  have watched the video too which slightly answers my question about replacing a Siemens with a Honeywell as its basically a switch, rather than part of the programmer (which I suppose is also a switch!!!)

The Honeywell in the video had 5 wires as does mine.

Any good places to get a Honeywell?

Thanks

Dave

 

[batty]

You will have to drain down as the whole thing will need changing you won't be able to just change the head.

 

[steptoe]

if you are prepared to do the work,

2 x 2port valves are better,

otherwise,

IMHO, honeywell are deffo far far superior than siemens.

 

[dave1510]

OK - I know it will be a drain down job anyway, so I could change the existing siemens for 2 x 2 port valves while I am at it... 

However, I do have a few questions regarding replacing a 3 port with 2 x 2's:

1, As the system was "designed" with a 3 port valve, will changing 1 x 3 port valve to 2 x 2 port valves cause any issues with pressures and or balancing the system?

2, Will I have any problems with the wiring (not physically, but connecting 2 x 2 port valves to the 5 wires going to the boiler)

3, do I just put 1 2 port in the heating line, and 1 in the water line?

...and should I opt to replace the siemens with a Honeywell...

3, which model is best

Thanks

Dave

 

[ProDave]

Pressure wise no problem.

But wiring, it's a complete rewire I'm afraid. The 3 port valve is wired completely differently to two 2 port valves, so everything will need to be rewired from the programmer, to the wiring centre to the 2 valves. But chances are you can re use the existing wiring runs

 

[dave1510]

Ahh - well that sort of answers my question - as I'm not into re-wiring the programmer myself.

Looks as if the simplest is to try a Honeywell then...

Any idea which model Honeywell will replace the Siemens CMV322 & DVA3?

(I have photos, but can't post link yet)

Thanks

Dave

EDIT to above:

Apparently the Honeywell V4073A is a direct replacement? (Is this the newer version - post #5 talks about a newer version which allows removal of the actuator without drain down)

Dave

 

[Steve3948]

If yours keep failing its most likely the main body not opening and closing with ease.

Change the whole thing and it should be ok for some time.

 

[dave1510]

I am on my 4th CMV322 in 5 years! - This one is playing up after 19 months - to me that is not long enough - I'd expect 5 years, is that unreasonable?

Looking at the posts that you have all very kindly posted, the Honeywell does seem the preferred option, on a like for like.

I would prefer to install 2 x 2port valves, but am a bit put off by the wiring changes.

Dave

 

[SPECIAL LOCATION]

I am on my 4th CMV322 in 5 years! - This one is playing up after 19 months - to me that is not long enough - I'd expect 5 years, is that unreasonable?

Looking at the posts that you have all very kindly posted, the Honeywell does seem the preferred option, on a like for like.

I would prefer to install 2 x 2port valves, but am a bit put off by the wiring changes.

Dave

Was the heating system properly flushed when first installed???

I'd expect more than 5 years!!

If you have had to replace that many valves over such a short period of time ..

either..

a)

you should be getting the supplier or manufacturer to replace them free of charge as the goods originally supplied were NOT of merchantable quality or fit for purpose....... 

b)

The whole system has loads of swarf and crap floating around in it mechanically clogging or damaging the valve..

The bit that actually closes the valve is only like a rubbery plug that is held across a pipe outlet inside the valve body.

Excessive sludge / corrosion / pipe swarf debris can prevent the valve body from moving fully.

3 port valves are controlled by heating ON and water OFF signals..

NOT a heating ON and a water ON which you would need for two separate two port valves.

The home position of the 3-port valve lets water through to the hot water cylinder...

No voltage needed to drive the valve.

To drive the valve to the furthest heating only position it needs voltages from the Heating On and the water Off signals. 

To stall the valve in the mid position for both heating and water it only needs the heating On voltage to drive it half way.  

It is possible that there is no Water ON wire at the 3 port valve itself...

depending upon distances between..

Valves, Main wiring center, Programmer & Thermostats, it could be easy to modify the wiring..

OR a right sod!!

If you say you are not confident of modifying the wiring..

Are you actually sure that the existing wiring is correct? as it does seem to be one helluva lot of failures????

:C

 

[dave1510]

[SIZE=10.5pt]Was the heating system properly flushed when first installed???[/SIZE]

[SIZE=10.5pt]Yes - I would expect Morris Homes contractors to have done this.[/SIZE]

[SIZE=10.5pt]At any rate, it was done under MH's warranty twice in the first 2 years.[/SIZE]

[SIZE=10.5pt]I'd expect more than 5 years!! [/SIZE][SIZE=10.5pt]Me too[/SIZE]

[SIZE=10.5pt]If you have had to replace that many valves over such a short period of time ..[/SIZE]

[SIZE=10.5pt]either..[/SIZE]

[SIZE=10.5pt]a)[/SIZE]

[SIZE=10.5pt]you should be getting the supplier or manufacturer to replace them free of charge as the goods originally supplied were NOT of merchantable quality or fit for purpose....... [/SIZE]

[SIZE=10.5pt]They were up to the last one in Feb 2012[/SIZE]

[SIZE=10.5pt]b)[/SIZE]

[SIZE=10.5pt]The whole system has loads of swarf and crap floating around in it mechanically clogging or damaging the valve..[/SIZE]

[SIZE=10.5pt]The bit that actually closes the valve is only like a rubbery plug that is held across a pipe outlet inside the valve body.[/SIZE]

[SIZE=10.5pt]I did have a look at the Valve last time it was done, and the little rubber stopper was slightly gungy, but not what I would have called excessive, but the plumber thought it was grounds for failure. (I had sourced the Valve, so he had no financial gain)[/SIZE]

[SIZE=10.5pt]Excessive sludge / corrosion / pipe swarf debris can prevent the valve body from moving fully.[/SIZE]

[SIZE=10.5pt]3 port valves are controlled by heating ON and water OFF signals..[/SIZE]

[SIZE=10.5pt]NOT a heating ON and a water ON which you would need for two separate two port valves.[/SIZE]

[SIZE=10.5pt]The home position of the 3-port valve lets water through to the hot water cylinder...[/SIZE]

[SIZE=10.5pt]No voltage needed to drive the valve.[/SIZE]

[SIZE=10.5pt]Collected with systems calling when ON - Programmer Lights all OK[/SIZE]

[SIZE=10.5pt]Voltages against Blue (N)[/SIZE]

[SIZE=10.5pt]Water OFF - Heating OFF = Grey 253v; Orange 0v; White 0v[/SIZE]

[SIZE=10.5pt]Water ON - Heating OFF = Grey 0v; Orange 252v; White 0v[/SIZE]

[SIZE=10.5pt]Water ON - Heating ON = Grey 120v; Orange 252v; White 252v[/SIZE]

[SIZE=10.5pt]Water OFF - Heating ON = Grey 252v; Orange 252v; White 252v[/SIZE]

[SIZE=10.5pt]To drive the valve to the furthest heating only position it needs voltages from the Heating On and the water Off signals. [/SIZE]

[SIZE=10.5pt]To stall the valve in the mid position for both heating and water it only needs the heating On voltage to drive it half way.  [/SIZE]

[SIZE=10.5pt]It is possible that there is no Water ON wire at the 3 port valve itself...[/SIZE]

[SIZE=10.5pt]depending upon distances between..[/SIZE]

[SIZE=10.5pt]Valves, Main wiring center, Programmer & Thermostats, it could be easy to modify the wiring..[/SIZE]

[SIZE=10.5pt]OR a right sod!![/SIZE]

[SIZE=10.5pt]If you say you are not confident of modifying the wiring..[/SIZE]

[SIZE=10.5pt]Are you actually sure that the existing wiring is correct? as it does seem to be one helluva lot of failures????[/SIZE]

[SIZE=10.5pt]See above for the permutations and Voltages - The faults are Intermittent.[/SIZE]

[SIZE=10.5pt]Thanks[/SIZE]

[SIZE=10.5pt]Dave[/SIZE]