Zone valve replacement

[<me9]

I had problems overnight with a Honeywell 2 port zone valve on my s+ plan system. The boiler was remaining on, due to a failed micro-switch.

I replaced the micro-switch, but feel the valve needs repacement/refurbishment, as there were signs of water leaking from the shaft seal.

The valve has lasted 6 years or so, Is this a reasonable life?

One of the other valves is a (newer) Danfoss one.

The Honeywell valves have a non-standard thread on the compression joints, so if I go for another make this will necessitate removing the olives in a confined space difficult to get to.

I have had a lot of trouble with Honeywell 3 port valve micro-switches in the past, but this is the fuirst failure of a 2 port valve.

Should I replace like for like, or would I gain any advantage changing to (say) Danfoss valves.

[<me9]

Brain fart theree, I meant Danfoss, not Honeywell.

Again should read Danfoss, not Honeywell.

Again read Danfoss.

I should have got more sleep, rather than pratting around at 2 am trying to work out why the boiler was on when there was no demand for heat.

[Set Square]

I would replace like with like for the sake of easy installation. I don't think that Danfoss valves are any worse than any other make.

[Christian McArdle]

They would normally last longer. However, 6 years is the statute of limitations, so there's nothing you can do about it and some will fail in this timescale even if there is no underlying cause.

With the strange thread, I'd replace like for like. However, you may find that the manufacturer now uses a standard thread anyway.

Christian.

[Fentoozler]

One thing I like about Danfoss is that you can purchase the valve body seperately (HSV3) whereas Honeywell only sell valve + head, or head on its own, therefore a pricey exchange is all you require is the body. Honeywell do sell ths insides for a valve (ball + plate) but I have never had any success with fitting these. However, conversely, you can replace the syncron motor in a honeywell head, but you are not supposed to do so in a Danfoss head.

Swings and roundabouts I suppose, Danfoss tend to be a bit cheaper.

Angus

[Martyn Pollard]

The disadvantage with the danfoss valves is that they are metal against metal. If there is any crud or corrosion, then the valve can easily become stuck fast.

With honeywell valves then you have the rubber ball against a metal seat which is more tolerant to debris.

[<me9]

The current 'Danfoss' ones have a rubber 'wedge' as the seal. I think I'll order a full Danfoss valve from Screwfix, and just replace the body, hoping it has the same threads as the old one. I'll keep the head as a spare I'm sure a micro-switch will fail at some time. The current problem is a leak around the valve stem, which I can probably fix with o rings, but it is handy to have a spare, so I can just replace the whole innards, as long as the main gasket is sound.

[Christian McArdle]

As luck would have it, I have just had a new Danfoss zone valve arrive this morning. I would be happy to see if the threads are the standard compression pitch or something weird if you can wait until this evening when I get home. Let me know if you would be interested.

Christian.

[<me9]

I'm not rushing to fix it as it's working at the moment(SWMBO would probably object if it is cold /again/ this week. I'll probably order later in the week. The old Danfoss thread is about 3tpi greater than the standard BS thread. Let me know what you find please.

[cmcardle75]

My new Danfoss valve has a thread that is substantially finer than a standard compression coupler.

HTH.

Christian.

[<me9]

Thanks. I'll go ahead and replace with another Danfoss.