sime diverter valve

Heating working fine the problem is with the hot water side,you can only have hot water when the heating is on,i looked through the trouble shooting guide in the manual i did what it said,hot water tap flow is as normal so it said change the diverter valve,i noticed that with the heating off when u turn on a hot tap the diverter valve piston is not coming out far enough to activate the micro switch.So i suppose what i am trying to say is does it need changing or can you clean them out and also are they easy to change. The model is a sime friendly format 80e.

You have got the same boiler as me
There is a rubber diaphragm inside the valve, and it sounds like its perrished. Get a new one from The boiler shop its easy to replace if your diy skills are up to it

Er, boiler parts shop!

Cheers for the speedy reply,so have you fitted one on yours, how long to fit and what needs draining down.
I just wish i had bought a proper boiler, not that its caused much hassle 'yet'.

just need to isolate your stopcock and release any pressure through a tap and release the pressure on the heating side through a drain off or a bleed valve on the radiator. Then you can take the microswitched off the dv, unscrew the front and change your diaphragm....be prepared for a small loss of water but not too much. This is all based on it being accessible in situ, you may need to remove the whole valve and fit new washers on replacement.

Well i took your advise went to the boiler shop today,got a diaphram and seal kit £22 for the lot ,better than £86.00+vat they wanted for the whole valve.I tried earlier to fit it but i couldnt get the last screw out of the valve body so i could fit the diaphram,so i will have to drain the whole system tomorrow and take it all off.
cheers all for your help.








chris.

YOu just need a small ratchet bit holder like the one in this kit:

Screwfix item 50593.

Look for a Draper one in a car accessory shop, £6.99 I think.

Cheers for all the advise,only i have done it now,i took the heat exchange off then took the d valve off fitted the diaphram put new seals on the heat exchange put it all back on the boiler,topped up the system and water shot everywhere,what i found was the new seal kit that the boiler shop sold me,the fibre seals where thinner than the original ones,so the old seals went back on but one is slightly leaking,so i can do that easy enough,i have a seal kit which i use for work hopefully that will sort it,but the best thing of all is the hot water works a treat.so thanks again.






chris

Its not christmas anymore.

Glad to help

I had a problem with a SIME Super 90 plus Boiler.
The symptoms were that when I had a shower, the boiler didn't start up unless I ran the hot tap at the same time. By talking it through with a friendly plumber we diagnosed that this was probably the diaphragm inside the Diverter Valve. This is a rubber diaphragm which when it has more water pressure on one side, moves a metal rod up which pushes the microswitch on which starts the boiler. (When I removed the old diaphragm, the rubber was corroded with a hole in it which explains why it wasn't working correctly.)

I was quoted by a couple of plumbers about £200 to replace the diverter valve so decided to have a go myself.

The process of changing the diaphragm was relatively straightforward - it took about 90 minutes.

(1) Order a new diaphragm:
I contacted MJT Controls (In Bristol UK): www.mjtcontrols.co.uk
They asked me for the Ref No for the boiler which was inside the front cover of the boiler which is a number which begins with 808 or 809 and four more digits. They can use this to check that you're ordeing the right part no.
The part no for a diverter valve with them is: 6102801
which is about £70 BUT I asked for just the diaphragm which was just £6 !! Delivered a couple of days later.

(2) Preparation
Remove front of boiler
Turn off mains water.
Relieve water pressure by turning on cold and hot taps in a sink.
Disconnect electric power to boiler (I did it by removing fuse)

(3) Remove Diverter valve.
It's a bit awkward as it's at the back right - a brass coloured unit with five pipes connecting and a black plastic unit fixed to top which is the microswitch. It's a matter of undoing the five nuts and then removing the three electric connections to the microswitch (keep a record on paper of the order)

(4) Change diaphragm.
Undo about 8 screw in diverter valve and open it up.
A large spring pushes the two parts apart. Remember which way these go so you can put it back together. My diaphragm had a hole in it.
Put new diaphragm in and push big spring down and put 8 screws back in.
(Note that the two side pipes go out opposite each other.

(5) Replace Diverter valve.
Revers of (3) - can be a bit fiddly.

(6) Finishing
Turn on water
Bring pressure back up by truning a tap underneath boiler so that pressure of boiler comes up to red mark ont he dial.
Run hot tap until flowing fully.
Put fuse back in to bring power back on.

(7) Have a nice hot shower!
Sit back and have a beer

Thanks for this thread - it made it possible for me to save about £160 !

Regards

Suhada

You say the shaft on the diaphram does not come out far enough to make contact with the microswitch. Is the same for all valves. I have a SIME Super 90 and have replaced the diaphram but on this one the shaft is already connected on the microswitch, I have to push the shaft at the top in to disconnect from the microswitch, is this correct.

I had my divertor valve replaced not long ago on my Sime friendly combi and i was only charged £100 including parts and labour. It sorted out where the hot water should go to but mine still has other problems with hot water. Its a Sime so expect more problems to come your way.