Some advice on two different problems please?

[PlumbBobBob]

you don't need to turn down the tank stat it must be at 60 degrees to kill bugs. it only needs moving down towards the bottom third of the tank

 

[fuzzy]

looks like the feed and vent are the wrong way round. swap them over, lower pumo below the bypass(wrong side of pump) and fir auto by pass valve. should fix problem

 

[coursemyhorse]

None of this is meaning much to me as I'm not a plumber myself. Is all of the advice given to fix the knocking problem only right? So what would be rough costs to get someone out to move the stat down lower (or can I do this myself?) and to sort out the bypass/valve/vent changes required? Would the work be guaranteed to stop the noise or would I pay anyway and then see if it works kind of thing? Just a rough cost estimate from someone...are we talking £50 £100 £500 ?

 

[tamz]

A Y plan (your system, with a mid position valve) does not under most circumstances, need a bypass.



As they have fitted one to the wrong side of the pump it is causing the water to short circuit with most of the water following the red line where it should follow the pink line back to the boiler. When on for CH only the bypass is cut out of the circuit and if on for HW and CH it won't effect it as much.

Close the bypass by turning the screw on the silver valve so that it is across the pipe.
You can leave the tank stat where it is. Turn it to 65 deg.
Your room stat sited upstairs is in the worst position (heat rises), and should really be downstairs. It doesn't matter what temp it reads or what your neighbours and friends set theirs at. Set it at what you feel comfortable at (and it won't be 18 unless you like wearing a jacket to watch the telly).

 

[fuzzy]

tamz has pretty much described the problems there for you. you can shut off the bypass which should sort the issue or better still resite it. yes in most cases it doesnt need a bypass as there is always a route for the water unlike an s but it is recommended

 

[coursemyhorse]

Thankyou! I 100% understand what you guys mean now having seen the above diagram. OK, so the chrome valve on the bypass...which way should I turn it to close it? I assume clockwise? It was at horizontal i.e. 9 and 3 O clock, and I turned it a quarter of a turn clockwise to 6 and 12 O clock and it started dripping as I turned it. It got stiff after a quarter turn clockwise so I stopped, but I think I could turn it more. Should I force it till it won't go any further or is a quarter turn enough? I don't think it is closed but not sure. Thanks all for the help so far. Also, I noticed with HW and CH on, I still think it knocks a bit. It is quietest when just CH on which would fit with info above as bypass not used then. It is def air in the pipes. Can tell by the way the pump sounds and behaves.

 

[fuzzy]

if the line on the top is in line with the water flowing its on. if its adjacent it is off, just use a slottede screwdriver to turn it the correct way

 

[coursemyhorse]

EDIT:

In that case then, it was already off as it was going accross the pipe before I adjusted it

 

[coursemyhorse]

I just turned it 180 degrees the other way to the off position to see if it made a difference. Not sure why it leaks when I turn it. Anyway, I turned the HW on on its own and so far it has not knocked. However, I think the knocking usually occurs only when the HW first starts up having been off for a while. First thing in the morning does seem worst (6:30am), however, it does do it in the afternoon when it comes on again around 3pm sometimes. I will test it tomorrow morning and see if anything has changed. Thanks for all your help.

 

[fuzzy]

is your cold water inlet the first pipe on the flow before the pump? the second one being 22mm and going over the cistern?