Beginner hot press valves question from a new DIYer

Seregwethrin

Hi,

I learned quite some DIY stuff but for plumbing I am at zero.

I am not looking to be an expert in plumbing but I feel I should know which valve does what on attached photos.

I feel I need to be able to turn off water from water tank in attic, turn off hot water, top up boiler, empty the pipes etc (might change taps)
I need to top up boiler but couldn't honestly.

Would anyone help me understand these valves on the photo please? The yellow valve under the boiler is also a mystery to me.
If you can guide me to some reading material I would also read them through. The hot presses I found on the internet are quite different to what I have on photos...

(For example a plumber came over to install the expansion tank and by playing with the valves there he emptied the water in pipes. That was like magic to me how it happened.)

Really appreciate the help.

Thank you

John.G

CWST = Cold Water Storage Tank in Attic

1 old supply from CWST to HW cylinder

2 Mains supply to topping up system for boiler+system
3 As above.
4 Balancing valve for cylinder coil to avoid coil "robbing" all circ water from C. heating.
5 cold water feed from CWST to bathroom. OR maybe mains supply.
6 Gas suppy to boiler.

Seregwethrin

John.G wrote: »

CWST = Cold Water Storage Tank in Attic

1 old supply from CWST to HW cylinder

2 Mains supply to topping up system for boiler+system
3 As above.
4 Balancing valve for cylinder coil to avoid coil "robbing" all circ water from C. heating.
5 cold water feed from CWST to bathroom. OR maybe mains supply.
6 Gas suppy to boiler.

Thank you for all this John, I finally got a chance to try all these today and you are spot on all these. I tested hot/cold water valves and they did cut off the water.

Though just before testing these my boiler had stopped with F9 possibly a low pressure issue bar at 0.9. It was saying the same thing before but resetting was solving, this time didn't solve and got stuck like that.

I tried the topping up system but interestingly valves were already open and I cannot top up the boiler. The valve number 2 is fully open clockwise, number 3 pressure gauge has two valves on the left and on the right something like a bolt that I can turn and take out (bigger photo is attached here). I am suspecting I am unable to control this properly to let the water get in. Any ideas on this?

Also, the "Balancing valve for cylinder coil" is also on the same pipe with number 2 and 3. I don't understand how 3 valves can be on the same pipe without pipe having any junction or getting into the cyclinder

John.G

I think that topping up pipe is connected in with a T just below the balancing valve?? (see my red line), and will then pressurise the entire system, even so it doesn't really matter.
The pressure gauge scale/range is far too high so be very careful, suggest communicating with somebody watching the boiler gauge while topping up.
The "something with a bolt" is the adjusting screw for the PRV (pressure reducing valve), so....ensure valves 2&3 open then slowly turn the adjusting screw clockwise until you feel a bit of resistance (around where that lock nut is which you may have to turn back a little further) then watching that pressure gauge very carefully which seems to be reading 0.5 bar at the moment? very very slowly turn that adjusting screw until the pressure rises to 0.9/1.0 bar (or as advised from below) 0.9/1.0 bar should give you 1.4/1.5 bar at the boiler assuming its on the ground floor.
When adjustments completed, tighten (nip up) the locking nut on the adjusting screw, this should be left in this position and just shut valves 2&3 and you are in business. (Bit surprising that low pressure warning/trip is up at 0.9 bar though, the increase should reset it)

Seregwethrin

John.G wrote: »

I think that topping up pipe is connected in with a T just below the balancing valve?? (see my red line), and will then pressurise the entire system, even so it doesn't really matter.
The pressure gauge scale/range is far too high so be very careful, suggest communicating with somebody watching the boiler gauge while topping up.
The "something with a bolt" is the adjusting screw for the PRV (pressure reducing valve), so....ensure valves 2&3 open then slowly turn the adjusting screw clockwise until you feel a bit of resistance (around where that lock nut is which you may have to turn back a little further) then watching that pressure gauge very carefully which seems to be reading 0.5 bar at the moment? very very slowly turn that adjusting screw until the pressure rises to 0.9/1.0 bar (or as advised from below) 0.9/1.0 bar should give you 1.4/1.5 bar at the boiler assuming its on the ground floor.
When adjustments completed, tighten (nip up) the locking nut on the adjusting screw, this should be left in this position and just shut valves 2&3 and you are in business. (Bit surprising that low pressure warning/trip is up at 0.9 bar though, the increase should reset it)

I have heating back on!!!!!! Thank you John it worked

Never thought the pressure adjusting screw should have been in, I was taking it out anti-clockwise thinking that will open that... So that's like a protection for accidental touches to the pressure adjusting valve maybe.

The pressure gauge was showing 0 bar in hotpress honestly but the boiler always showed 0.9. I think the pressure was even lower than 0.9 but boiler didn't seem to show anything less than 0.9. I set the pressure gauge a bit over 1 bar in the hotpress and it became 1.2 in the boiler too, interesting! Maybe the pressure gauge is an adjusted one for the being on higher ground.

I made a 20 seconds video here following the topping up and balancing valves. You are right again, it is connected with a T at the bottom going to somewhere maybe boiler or to the radiators... https://www.youtube.com/watch?v=702lDIogYCw

I am finally understanding this more thank you
I am reading a bit more about balancing valve and how whole system works, then time to try to replace the 20 year old taps maybe :rolleyes:

Though when I opened the balancing valve fully, it started to leak a few drops of water and I opened it about half fully after that. That was interesting... I guess it should be kept like that.

John.G

There is a gland nut on the top of the balancing valve which you should be able to tighten up a little to stop that leak, if you do find the rads are running a bit cooler then just shut the balancing valve and then open it 3/4 to one full turn.

Seregwethrin

I tighten the gland nut on the balancing valve and opened the balancing valve 3/4 turn only.
Thank you for all these John. It kept the house from freezing

I was reading around and I understand when balancing valve is shut the hot water cylinder doesn't heat and we open the balancing valve to provide the most current to the radiators and a bit to the cylinder the if I am understanding correctly.

May I get one more insight from you, when someone was installing the expansion vessel, he was able to empty the whole system and told me water went out from the back behind the boiler. I am still curious how he did that. I assume he closed the system top up valve and opened a valve maybe in the boiler to let the all water go out, any ideas on this?

John.G

Correct re balancing valve, the heating coil has the least resistance so by throttling the flow through it you are forcing more water through the rad circuit.
Looking at pic 1 in post #1, there may be a drain valve on that white pipe (under "Flexicom 18 SX) that exits through the tiled wall on the right, follow it and see if it goes to drain, I'm not very sure because the drain valve should be visible just under the boiler. Even if that is the drain, it will not drain the ground floor rads as the boiler is higher. You may find a drain on the end of those rads that a hose can be attached to. I will post a pic later. And yes, you keep the top up valves shut while draining.

Seregwethrin

Thank you for all these John, my boiler is working all good so far and now I have a better understanding of what can cause what

I followed the white pipe and yes it goes to outside drainage so that must be the drain pipe but couldn't find the valve, maybe it's under the boiler's cover but I don't need that now anyway and hopefully will never need to drain the system.

Really thank you much appreciated, I can try to change kitchen and bathroom taps now with something easier to use at least

Seregwethrin

so I think I found how the plumber emptied the pipes!

I think he closed the inlet and opened the outlet pipe and let the air in and let the water run outside!

Because when I was re-attaching a radiator, which I had taken out previously, I opened the outlet valve first and I think air got in but when I opened the inlet valve the pressure was zero.

Also, at the drainage pipe outside there seems to be two pipes going outside. So one of them could be like an overflow... Because when I didn't have expansion vessel the plumber told me when the pressure was going beyond some point it was going outside from one of those pipes which was keeping the pipes not blow up.

Attaching the photo related to that one. This is very interesting to trying to understand this

John.G

Your system is known as a sealed system which will have a expansion vessel which is pre charged at the air end to 1.0 bar, on installation, it is then pressurised at the water (system) side to 1.5 bar, when the system heats up, the water expands and will enter the expansion vessel and the pressure will then rise to ~ 2 to 2.3 bar, if the expansion vessel fails internally (punctured rubber diaphragm) or the air leaks out of the air end then it will fill with water and the expanded water has no where to go so it will lift the boiler safety (PRV) valve at 3.0 bar and discharge it outside. Some boilers like Grant have this setting at 2.5 bar.