outside oil boilers freezing

Well its either cold, or cold and hot is correct. It can't be both.

Your taking a big assumption there that building regs have been complied with, or that the system was installed or modified after the regs came into force. Or that its working as designed with out any failures.

How do you top it up if its disconnected? (regardless of why).
 
I am not sure what you are talking about, re: hot and cold. I made a statement about contamination of inhibitor/anti-freeze into the domestic supply from the heating circuit. The only place where they meet is at the coil in the cylinder or as you correctly pointed out at the filling loop if the loop is an automatic filling valve. This will also have a non-return valve.
With regard to how is it topped up, the system will have 2 stop valves and flexible hose. Just re-connect the flexi-hose, open the stop valves until the required pressure is achieved, close valves and disconnect flexi-hose. This system will also have a non-return valve installed to prevent back feed of heating circuit water into the mains feed, should the pressure be greater.
 
One system I saw was filled from the attic tank. No non-return valve. Someone left it open working on something else, and the system back filled into the tank. The tank feeds the hot and cold water taps, say to the bathroom. So its not beyond belief that someone brushing their teeth would ingest some of this water. Or just take a drink from it. The only cold water not fed from the tank is the kitchen. I'm mainly in the attics of older houses and I've never seen disconnected filling loop as you describe, even in houses only 10yrs old.

I guess my point is real life is often not what always by the book.
 
I have never heard of filling a pressurized system from a tank in the attic, as you would never achieve the required pressure from gravity in a normal size house. It would have to be quite a few floors high. Of course, if the clown who did so tried, the pressure of the heating system would push the heating water back into that tank. It's certainly a new one to me.
Filling loops are only in pressurized systems, so you will never see one in an attic. They are normally located either close to the boiler or in the hot press, etc. Vented systems are filled by the expansion tank (the small tank in the attic), hence called the feed and expansion tank. This is only on gravity systems. The F & E tank is fed by a ball valve so it does not have a direct feed from the cold water supply and heating water could not pass back into the cold feed.
You are certainly correct about real life and the book!
 
But it should be by the book, people wonder why we get so many boiler breakdowns, it is normally from shoddy 'not by the book' installations
 
But it illustrates your point about the danger of antifreeze. The end user may not know their system is flawed, until theres a problem.
 
[QUOTEI would recommend installing an additional pipe stat, fitted to the flow pipe from the boiler and set to 30C. This will turn off the boiler when the water within the flow pipe reaches 30C..[/QUOTE]

shane007, are you possibly using this stat to break the connection of the frost stat, surely you can't install this on switched live or permanent live circuits...???
 
There is nothing uncommon with filling a sealed heating system with a 45 litre feed and expansion cistern. I've seen countless installations done this way.
This cistern tops up the cistern has a 15mm feed pipe that fills the heating up automatically when needed. This feed has a check valve incorporated to stop expansion up into the citern.
Expansion within the heating system is accomodated within the usual expansion vessel.
This permanent feed will stop the need top up the heating via the mains supply cutting out needless service calls due to low pressure cut outs.
 
Hi Esox, yes you can. Permanent live to frost stat (independent of timed live or switched from timeclock), wired to pipe stat, then to switched live on boiler. Our electrician confirms this who does all our wiring installations.
 
villa 1 said:
There is nothing uncommon with filling a sealed heating system with a 45 litre feed and expansion cistern. I've seen countless installations done this way.
This cistern tops up the cistern has a 15mm feed pipe that fills the heating up automatically when needed. This feed has a check valve incorporated to stop expansion up into the citern.
Expansion within the heating system is accomodated within the usual expansion vessel.
This permanent feed will stop the need top up the heating via the mains supply cutting out needless service calls due to low pressure cut outs.
Click to expand...

Well this is a new one to me. I have never seen it in 24 years and I hope I never do! Why would you even want to do it in this way. It won't work and if you have a pressure drop, it is highly likely that you have a leak, so therefore, fix the leak and not automatically top up to hide the fact. That is another reason why disconnecting the filling loops are an advantage over a gravity system that tops up if there is a leak. It will show up on the pressure gauge, i.e. zero pressure.
Sealed system with a cold pressure of 1 bar or a hot pressure of 2 bar will require a minimum heat height of 10m and 20m respectively to fill (0.1bar per meter of head height). So if there is a pressure drop, how can the system possibly top up from a gravity fed system??? You will not achieve the required pressure to fill the system. So what you are saying is basically nonsense. Your needless service calls due to low pressure cut outs are not so needless. If there is a pressure drop in a sealed system, it means there is a failure within the system, either a blow off from the 3bar safety valve caused possibly by a failure in the expansion vessel diaphram or a leak! Most householders would not know how to fix this and if you go along and install your so called fix, then I am afraid it is time for me to hang up the boots and let you off....
Apologies for ranting, but get real.
 
You can rant all you want 007 and I am getting real.
I am 35 yrs in the business in this country both in a contracting and training capacity. I am a time served plumber( in one of the best apprenticeship systems in the world, fact) so don't even try to question my experience. I've heard so much good talk about the NVQ training system in the UK!!
I am fully aware of the static/working pressures within a heating system both open and closed, yawn!! It is quite feasible for a boiler to work in a semisealed system once the system head for that particular boiler is satisfied. This is an option, depending on the heating appliance and I have indeed seen several systems working perfectly in this manner.
What would you do with a solid fuel heating appliance. Would you pressurise that as well. These particular systems are all over this country and are they all leaking?
You need to do a few more short strand training courses before you become a complete expert!!
 
Villa1, I am astonished by your attitude and your personal attack on my qualifications and where I obtained them. This is a forum for helping people and if you wish take it to a personal level, then I am not interested in your innuendos and sarcasim.
1. I still disagree with your theory of filling a pressurized system from a gravity feed. For example, a bungalow with room height of 8ft and 9" ceiling joints will give a head of under 3m. This will give a static head pressure of 0.3 bar. How are you going to pressurize a sealed system to 1 bar from 0.3 bar of pressure and why would you try when you can fill with a filling loop with mains fed pressure? Double this for a two storey house and you still only have approx 0.6 bar of pressure.
2. With regard to solid fuel, nobody mentioned these as we are only speaking about pressurized sealed systems and of course if we were, we would not be pressurizing the system and therefore filling the system from a feed and expansion tank in the attic.
3. Nobody also stated that all systems are leaking. We are discussing filling a pressurized sealed system. I think you have lost your trail of thought and are trying to focus too much on a personal attack, which I believe is showing your wonderfully trained character.
4. If I am incorrect, I will gladly and openly admit so and I have no problem in doing so, but please show me in detail, in theory, in any which way you feel comfortable, but please do not try to slander my character.

Forums are wonderful places for the general person to obtain information from eachother and we all can learn something. If situations take turns as this has, then I am afraid we have turned a win win situation into a lose lose situation. I apologise if your ego or anything else has been offended, so I will bow out and leave you to whatever you do best.
 
I love the way they even adopted the name 'automatic filling loops' for pressure reducing valves, it's great they are no longer allowed, it's a pity it's not enforced!
 
Shane 007 sorry for tweaking a nerve but you told me get real and in my estimation that is saying that I do not know what I am talking about. Bad Idea!!
I will have to re-iterate what I have already said in plain language, so lets go again.
You can feed a system boiler, gas fired, from a feed and expansion cistern and if you want proof I can pm you the housing estate(s) which is served by the Bord Gais network.
Householders/building owners have to pay a plumber to recharge their pressurised heating system when boilers lock out due to low pressure brought on by minute leakages in pipes, fittings and gland packings in valves, not leaks!! This expense will go when the system including the heating appliance is fed from a feed cistern (which of course will satisfy the necessary pressure/head requirements).
I certainly agree that forums like these are great learning facilities and I get great pleasure in giving free helpfull advice to anyone who requires it. But you started the "spat" and I had to no other option that to give likewise back.
End of, and have a nice day!!
 
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