Primary return valve

congo_90

Hey all,
Had dropped some towels down the back of the hot press a while ago *doh*

Anyway as I was leaning in i moved the primary return valve. From moving back and forth etc. Anyways I'm not too sure on its original position. I've left it a bit open for now anyways as I know this goes back to the boiler?

The concern I have is that I noticed water coming from the expansion pipe outside. Or rather saw dampness from where it must have expelled some.

Could this be down to the valve position? the boiler pressure is around 1.2 bar hot and 0.5 bar when off (cold).

As for the hot water cylinder.. Pressure is usally 3.2 bar consistantly (partially down to a water pump in the attic). It's above red line but my concern is that valve first.

Would I be right in thinking having it too open will cause reduce pressure in the heating?

I've attached a pic of the valve. For the record i'm aware a sheet fell! Sorry for poor quality but it was taken using a phone.

The valve would be a for balancing a heating system and cylinder, it's there to cause a resistance so the water being heated by your boiler gets pushed around the rads and not just have everything going to the cylinder, by closing this wheel head valve you can stop the flow of water to the cylinder coil stopping the cylinder from heating, if it were me i would have that wheel head valve fully open as a unvented cylinder(which it looks like) has a massive coil 26/30 kw and the reheat time is very quick, even if it robs the heat from the rads the cylinder is going to get up to temperature quickly and then shut off the motorized valve(which must be fitted for safety) which will then cut all movement to the cylinder pushing everything around the heating circuit. If you are seeing water outside then that can come from the boiler safety valve(this would mean loosing boiler pressure) or one of the two safety valves on the unvented cylinder, water leaking from a cylinder safety valve should be looked as a warning and it's very important to find out why it's leaking, Gary.

congo_90

hi gary. I'll attach another pic now to my suspisions to why it may be discharging from the cylinder

I suspect the boiler is not leaking at itself because i never see water on the wall where it is having said that its very exposed compared to the cylinder location

That is the pressure valve located for the cold feed into the boiler. I know this from when I bled the rads and had to refill the system. From what I've gathered the pump in the house keeps this pressure at a constant 3.2/ 3.5

For the record the boiler cold or hot isn't great on pressure yet all rads and water is always hot.

congo_90

I'll try add better/ higher res pics this afternoon

If you're heating system is filled via a filling loop (http://www.shopwiki.co.uk/_Combi+Boiler+Filling+Loop) your boiler would need to be filled to 1-1.5 bar by you, if the boiler safety valve was leaking you would have to top up the heating system to maintain the pressure, if your boiler is fed by a tank in the loft or a auto filler then you could be losing water from your heating circuit and not know it, the water would be replenished by the tank/auto filler. I am assuming you have a unvented cylinder and as i already posted water leaking from a cylinder safety valve is a warning that the cylinder is not coping with the pressure inside of the cylinder, this is a bad thing and you will have to find out why, i would make sure you are not over heating the cylinder and that you have it thermostatically controlled and wired to a zone/motorized valve so that when it's hot enough the heat stops flowing to the cylinder, the expansion vessel for the cylinder would need to be checked for correct operation, long story short if it looks like the cylinder then get it checked, if you don't have a unvented then ignore the above:D, Gary.

congo_90

Hi gary. I took a look and followed your advice.
The system leaked again from the safety valve last night. I heard it dumping the water and then the pump engaging later. I think I'll have to call in a plumber. There is a thermostat on the cylinder but I think that is the immersion control. It's a newish house (3 years). The heating has 2 zone thermostats. Upstairs and down.

If it is a unvented cylinder you can then try leaving the heat off to it for a day, if the leak stops you know it's heat orientated and the cylinder is not coping with the pressure being generated from the heat, if it still blows then you may have to look at mains coming in although the cylinder is tank fed it's possible if you have a mixing tap in the kitchen for the mains to cross over and at night the pressure can ramp up. the stat on the cylinder would be for controlling the heat from the boiler, the stat for a immersion tends to be on the body of the immersion, Gary.

congo_90

So gary,
In lame mans terms the switch on the boiler for output is controlling the heat and the stat on the body of the cylinder is for immersion? I'll lower the boiler tomorrow. Do note, the boiler is on no more than 90mins per day and when the discharge happens is about 5-6 hours later. The boiler I suspect is low pressure always yet the cylinder was never reliever of this pressure.
As predicted by you the motor valve kicked in.

Is there any other valves i should be concerned about? I'm asking before I call in a plumber to look. Worst case scenario is it's something trivial which would save me a call out charge of sorts.

If you have a unvented cylinder for it to operate safely, there would have to be a cylinder stat connected to a two port/zone valve controlling the temperature of the cylinder, if the boiler stat is controlling the temperature of the cylinder then the cylinder can be over pressurized. To help identify the reason for the discharge you can try taking heat away from the cylinder ie.. make sure the immersion is switched off, turn down the boiler stat, turn off the wheel head valve you opened at the start, this would be done just to see if the leak stopped, once you have proved it's not heat orientated then you need to have the expansion vessel charge checked and any mixing taps because the taps can back fill a cylinder, after all of that it could be just a faulty safety valve (which i doubt), Gary.

congo_90

Hi gary,
I'll get on that tomorrow morning when the heating is off. Would putting pics of the cylinder/ boiler be any use to you? Thanks again for the sound advice.

pics would be good, you can never have to much information.

congo_90

This is the system in the hot press (click on pic for larger view)
Edit; There is a control thermostat just out of sight on the bottom of this pic.



this is the presure gauge as seen above the cylinder. I noted when I bled the system off myself the pressure lowered. I resumes high pressure where it's at when the heating was on. If an appliance was on and the pump kicked in (for everything except the mains in the kitchen). The pressure would reach 4.6 bars! :eek: I looked at the pump up in the attic. On the side it says 1.2 bars operation (not adjustable).



This is the cylinder info. On a side note. I couldn't find out if this was insulated or not.

Just to note that when I closed the valve and bled off the system to 'normal pressure' it stayed while when I left it open the the pressure would slowly rise to around 3.2 bar

congo_90

Page 7 here
shows some interesting layout of the cylinder. Just to note the expansion vessel is located in the attic. Before any of the fixtures shown

Whats interesting is the cylinder seems to want to run at 6 yet I'm concerned about the red line on the pressure gauge and secondly why the system is losing water.

Right, the safety valve in the picture is a 6 bar discharge valve it's pipe should be connected to the other safety valve pipework before the plastic tundish, which is on the right hand side of the picture, this is so if the 6 bar opens the water can be seen easily as a warning, the gauge by the safety valve is showing you the pressure on the cylinder side, as the cylinder gets hotter the pressure can increase, the expansion vessel should be fitted as CLOSE as possible to the cylinder on the cold feed with no isolation valves between them, the filling loop is connected where the manufactures want the vessel connected, you need to make sure when you turn down the cylinder stat on the bottom of the cylinder that the zone valve switch's off, it's the one nearest you as you look in the cupboard. To answer you're question the red dial means nothing it is just a indicator that can be moved manually by a installer, you have a 6 bar safety valve and a 7 bar safety valve, i would say it's the 6 bar and your cylinder is getting to hot, I'm a trouble shooter for another cylinder manufacturer and over cooking a cylinder due to bad installation is very common, that's not to say yours is wrong but your expansion vessel is not as the manufactures instructions, so read the instructions for your cylinder and make sure everything matches and the things that don't then have them checked, Gary.

congo_90

So I know this thread is over a month old but I thought i'd give an update incase anyone was searching for a solution as to why their house was p*ssing out hot water.
Had a plumber in fixing a broken pipe (thank you winter). Got him to check why the system was losing hot water and he reported back it was the pressure vessel for the cylinder and another one. The builder had put the wrong one in and one of the vessels gave up.

items

Common mistake, to some plumbers un vented cylinder is a new concept.

Red vessel for heating.

Blue and white vessel for plumbing.

Red vessels as far as I know are mild steel, mild steel rusts, if a mild steel vessel is used along with fresh water, it will rust inside, rust prob damaged vessel diaphragm in your case so no hot water expansion could be taken up, cylinder had to much pressure, hot water then passed out safety.

Blue and white vessels are made of stainless steal, fresh water wont damage stainless.

congo_90

items, Thats precisely what my plumber said! Luckily we had a "spare" vessel (white) lying in the shed from when they were fitting the pump to the houses. Both myself and the plumber reckon they intended to install the white. Its defo busted anyway as you can hear the water in it.

*edit* (above and here).
Any idea from previous pics if my cylinder is insulated? Was thinking of lagging it and the pipes as far as i can reach

items

congo_90 wrote: »

items, Thats precisely what my plumber said! Luckily we had a "spare" vessel (white) lying in the shed from when they were fitting the pump to the houses. Both myself and the plumber reckon they intended to install the white. Its defo busted anyway as you can hear the water in it.

*edit* (above and here).
Any idea from previous pics if my cylinder is insulated? Was thinking of lagging it and the pipes as far as i can reach

Fitted the exact same cylinder in my folks house, copper craft rings a bell. Cylinder is glass insulated like a flask. No need to add additional insulation. Don't even insulate pipes, if you do, your hot press wont be so hot anymore, not much need to insulate pipes located inside a house, they are all giving off heat inside house so its not really wasted if you think of it that way. Everything adds up, heat given off by internal pipes add to household heat. If your cylinder was in a garage then insulate pipes.

If your hell bent on insulating them, use cable ties to hold insulation to pipe, sticky tape will fall off eventually, lots of dragging about in hot press insulation thats not proper will fall of.

congo_90

I won't insulate the pipes so. Means I can save a few bob. Only thing i'll say is it does be warm in there naturally from the heat so thought it may not have been insulated.

items

It's pretty much impossible to trap all heat in cylinder, some heat does escape but with your cylinder its within a tolerance acceptable. Not sure if you've tested how long cylinder can hold a decent level of heat but from memory, copper craft can hold onto heat well over a day, next time cylinder stat is satisfied with heat, shut off hot water @ timer and test how long heat is held, you'll be surprised how long it holds. Majority of heat is coming from pipe work judging from previous picture, cylinder is just keeping heat in hot press ticking over.