Isolation Valves

Hi Everybody
I am hoping for some general advice after receiving a quote for lots of work to improve our central heating system.
After much research into possible issues, we have got to adjust lots of the pipework in our airing cupboard and loft (as shown on a previous post) as we are currently pumping over and sucking air in and have quite poor flow down to the ground floor (3 storey house).

Our fitter has also noticed that the entire system seems to be filled with 15mm isolation valves - cheap ones that he says are creating resistance in the system (squeezing the flow down to 8mm) and generally leak if you ever have to use them.

He is proposing to locate and remove them all, so that when we have a power flush done it has less chance of springing a leak at those weak points.

Can I just check that this is necessary? ( I will ask him directly but feel I need to educate myself before having the convo with him)
Although we feel for the amount of work being undertaken our quote is quite fair - it is still a lot of money in one go - and are still anxious that it won't fully fix our issues. We are trying to see if there is any work that might not be necessary or perhaps something that is fairly straight forward that we might be able to do ourselves or do at a later date.

Also can anyone give a rough estimate as to how much it would cost to actually rip out all airing cupboard and loft pipework as well as the condensing boiler and HW storage tank and just start again? I am beginning to wonder if that might actually be more beneficial.

I know this is quite a difficult question to answer as it changes on my location and the state of the system etc but a guestimate would help.

Thanks
M

Ask the engineer that has quoted you for the other works, as he has actually seen the job so knows what is involved, no one on here can give you even a rough price without seeing the job, I know one who will but just ignore him.

1. Quite agree with removing the isolation valves, particularly if they are cheap ones and / restricted bore.

There should be an isolation valve fitted in an accessible position close to each outlet (hot and cold). Fit good quality ones (e.g. Pegler) and if flow is an issue, fit full bore ones. For wash basins consider fitting flow limiting ones to ensure that with the taps fully open the overflow can cope with the inflow to the basin if the plug is left in (children!).

Don't fit isolation valves in the central heating circuit except perhaps to enable the boiler to be isolated without using its own valves (which often leak). Again good quality and full bore, and make sure they are rated for the temperatures involved.

2. As ianmcd says, no one can give you even a guideline on price without seeing what's there.

Thanks guys
Isolation valves have been fitted through out the central heating circuit - most annoying!

What would you replace with? A coupler joint? or solder in another piece of pipe?
Some of the valves are in a very difficult location under the ground floor - only accessible by a small void under the floor!

Small piece of pipe and two straight couplers, end feed.

If little movement available on pipework, use slip couplers. These have no internal stop.

1. Remove isolation valve, remove / cut off olive.
2. Measure and cut pipe, clean old and new pipes.
3. Clean inside of fittings (couplers).
4. Mark half length of fitting onto each end of new pipe.
5. Flux ends of old and new pipe.
6. Put fittings onto pipes (doesn't matter which).
7. Adjust fittings to touch marks on new pipe.
8. Solder. (Pipes must be bone dry).
9. Clean any excess flux off with wet rag once cool.

It would be best to flush all altered pipework before fitting new boiler.

Wow thanks for the info.
we aren't having a new boiler as yet, but all this is really helpful. Thank you

most iso valves are not rated for central heating temps so should not be used.