Fitting a 3 port valve

louisaL

following on from my other question. is fitting these valves 'easy' to do or really a job for an expert?

and DH is saying does the system need draining, and will water spurt out everywhere if he changes it without emptying the system?

EliteHeat

Yes, you need to drain down to a level below the 3PV.

If you are doing a like-for-like swap then you can reuse the old nuts and olives. If you are not, then there is no guarantee that the old threads or stub distances will be the same so they should all be removed. Some 3PVs were plumbed too close to elbow fittings, making the olives inaccessible and so sometimes this job can go horribly, horribly wrong.

You should be OK though

louisaL

thats great. we've been advised to get the horstmann 3 port valve from screwfix and swapping from a honeywell.

would they be different nuts etc?

duncan303

Save all that you will have drained, and use that to refill the system, as it may have inhibitors in it.:money:


..

keith969

Why change the valve from the Honeywell? If you get the same type as a replacement then as eliteheat says, its just a case of undoing the nuts and swapping over the unit. I did this recently as the valve in mine was sticking and its a simple job.

louisaL

thanks so muchf or your advise guys!

its all about money (as usual!) i'm afraid keith. the honeywell is £79.99 whereas the hostmann is £29.39 from £41.99 at the moment at screwfix.

keith969

You can get the Honeywell valves cheaper - around £50 if you google.

Remember you get what you pay for, read the reviews of the Horstmann:

http://www.screwfix.com/prods/93941/Plumbing/Central-Heating-Controls/Horstmann-3-Port-Motorised-Valve?cm_mmc=GoogleBase-_-Datafeed-_-Plumbing-_-Horstmann%203%20Port%20Motorised%20Valve#reviews

ormus

the fittings should be the same, but the actual dimensions maybe different. that may cause a headache?
maybe you can check the dims on the two makers websites.

EliteHeat

ormus wrote: »

the fittings should be the same, but the actual dimensions maybe different. that may cause a headache?
maybe you can check the dims on the two makers websites.

Do not assume the thread pitch will be the same, it probably will not be. The actual 'footprint' of the valve will almost certainly be identical though, but this does not mean that even if the threads are the same that the unit will be watertight.

You must renew the olives and the nuts with the ones supplied with the new valve.

P.S. The Honeywell is the best 3PV on the market and for the sake of a few quid you would be crazy to use a cheap plastic one.

P.P.S. If you have the removable head model, then you can just buy a power-head which means you don't have to drain down. This will work if the valve has not siezed, test this by advancing the manual actuator - if the valve opens then it is OK.

louisaL

thank you everyone! i've had a word with a friend's husband who own his own boiler repair company and he has agreed to fit the part and service the boiler for £100 (he couldnt get the part any cheaper than £100 plus vat!) so we will probably be going down this route so we know its done properly.

DVardysShadow

Although it is solved, it may be worth mentioning that not all 3 port valves are wired the same, besides the other differences.