Potterton Puma wax capsule

I used stopcocks to isolate the boiler which are the right way round, there is no way all the taps have simultaneous gone from working perfectly to all being blocked.
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No but we do come across stopcocks fitted back to front and the jumpers can then stay jammed on the seat despite the valve being "open".
Thought it was squirting water??

Current stopcocks are supposed to have pinned jumpers!

Here's my pic again
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I removed and refitted the manual flow adjuster which was a waste of time but now the DHW flow switch has sprung a leak in 2 places even though this is one of the few components I haven't touched, How tight should the screw on the top of the expansion vessel be?

Am looking with suspicion at the 1966 fitted stopcock under the dhw outlet but I can't undo the nuts, there is green stuff around them, is this a weld of some kind?
The screw on top of the mini expansion vessel is just a cap on the valve - just hand tight. The vessel is probably flat anyway so don't worry about it.

The flowswitch has 2 x 1/4 fibre washers - just pinch up the nuts a little and hoprfully that will sort the leaks.

It may be easier to remove the spindle assembly from the stopcock - if its siezed up you can often just replace the guts from a new stopcock and save yourself removing the complete valve (since you may not be able to spring apart the pipework). Otherwise WD40 on the threads and elbow grease. My 2 foot adjustables do the trick. ;)
The manual has been updated. The fig 2 in my old manual is fig 1 in the parts arena manual for the puma 100. The item nos in the manual don’t tally with the picture gasguru supplied the link for so you have to cross compare. The nearest fig in the parts arena manual to the gasguru picture is fig 17.

For no water at all to come out of the taps it’s got to be something easy to detect.

For me you’ve got to trace the mains water pressure around the boiler. From fig 1 the points around the boiler are:

1) mains inlet isolator valve (item 20)(item 91 gasguru pic)
2) DHW manual flow restrictor (shown in fig 9 & 13)(item 98 gasguru pic)
3) Wax capsule head (part of item 12)(item 84 gas guru pic)
4) Heat exchanger (item 5)(not shown on gasguru pic but fed from pipe 48a and delivers to pipe 45)
5) DHW flow limiter (to the left of item 22, spare part item 22 in fig 32)(item 108 gasguru pic)
6) DHW tap outlet

Suggest you disconnect each in turn and prove you’ve got pressure on each of the outlets by turning the mains on slowly. I don’t know much about the DHW flow limiter and there is not much in the manual. Of the rest I can’t see them stopping the pressure unless some foreign matter has caused a blockage.
There is a straight compression joint under the DHW outlet which has pressure, the old stopcock makes no noise when opened so looks likely. May have to cut the pipe and start again but access very difficult as it is between 2 other pipes with little gap, must buy parts first before starting, my 10" adjustables are inadequate.
suspicion at the 1966 fitted stopcock under the dhw outlet but I can't undo the nuts, there is green stuff around them, is this a weld of some kind?

i think your on the right track. the green stuff is just corrosion of the copper. i find blow torch heat (if you've got a heat mat to protect the surroundings) helps if the WD40 is not enough alone.

ChrisR, sorry about the stolen pic. now that i've looked at the detail of the link i see the error of my ways :oops:
Thanks for all 39 replies, we now have hot water after 13 days of carrying large pots of water upstairs boiled on the stove and we have central heating too. Cut off the old stopcock with a hacksaw blade and put in a new one. My plumbing is improving, but I still prefer electrics.

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