Cutting into a closed system

[soccercelt]

My brother is fixing up a house and after lifting up the concrete floors, all copper pipes where damaged! It's a closed system and were wanting to know, is it a case of just connecting new pipes to same, fill up with water then turn on or is it alot more tricky than a open gravity fed system. Both us have years of experience on gravity fed system but not any in a closed expansion vessel system.

 

[Scott_1979]

Yeah just cut into it and refill with with a filling loop and just take air out of the system in the usual way. I.e. Bleeding Rads. Remember to pop some inhibitor in the system

 

[joni os]

Provided you follow best practise procedures with your soldering the pipes won't care which system is in place. I prefer working on a closed system as it's easy to create a vacuum and avoid necessity for complete drain down.
Also easier to purge air from system.

 

[soccercelt]

Yeah just cut into it and refill with with a filling loop and just take air out of the system in the usual way. I.e. Bleeding Rads. Remember to pop some inhibitor in the system

Provided you follow best practise procedures with your soldering the pipes won't care which system is in place. I prefer working on a closed system as it's easy to create a vacuum and avoid necessity for complete drain down.
Also easier to purge air from system.

Has anyone any good diagrams I can follow. One thing I was getting confused with was seen 2 other 3/4 pipes near the boiler and can't see where they are going. Boiler in a tight location and hadn't lifted that floor yet. I was also curious incase closed system was dangerous if not plumbed correctly or I must be getting mixed up with a pressurised system.

 

[Riley]

They are both pressurised systems if you are this is unsure it might prove sensible to get a pro in

 

[soccercelt]

They are both pressurised systems if you are this is unsure it might prove sensible to get a pro in

I know a gravity fed open system inside out. Plumbed all my houses out in this method last 20 years and never had any problems. In fact, have worked on these systems with other plumbers. I do understand your concern about getting a pro in but all I need is some small info and could do this myself. It'd just a few issues needing ironed out. It's not as if I'm some rookie who doesn't know anything about plumbing/heating systems. Hopefully with help on here, I could get this completed over the wknd.

 

[Riley]

Fair enough you understand why we err on the side of caution as we have no idea of the capabilities of people using the form

 

[Best]

Sealed systems and open systems are just same pipework possibilities. (Except you don't have a feed and vent on open system. And some open systems have gravity pipes to cylinder, whereas sealed are normally always fully pumped)
Are you perhaps thinking of unvented hot cylinders? They are dangerous if installed wrong
You really need to get someone to check what you have and if nobody else is maintaining the system regularly then it should get some work. The expansion vessel needs its air charge done every year or so, close to whatever the cold fill charge is normally, for example. No point in just working on a system without knowing it is all safely done and complete

 

[soccercelt]

Sealed systems and open systems are just same pipework possibilities. (Except you don't have a feed and vent on open system. And some open systems have gravity pipes to cylinder, whereas sealed are normally always fully pumped)
Are you perhaps thinking of unvented hot cylinders? They are dangerous if installed wrong
You really need to get someone to check what you have and if nobody else is maintaining the system regularly then it should get some work. The expansion vessel needs its air charge done every year or so, close to whatever the cold fill charge is normally, for example. No point in just working on a system without knowing it is all safely done and complete

You see, this is what throws me off. I checked water tank in attic and there is what looks to me as an expansion pipe going into main water tank. Can't find an expansion tank, seen expansion vessel in hot-press so to me, I think it's closed system and if it is, I never knew it needed an expansion pipe. ill have to double check everything tomorrow.

 

[Riley]

Mate it sounds like you're getting the systems very muddled stick a few pictures up and we'll give some ideas

 

[Best]

You see, this is what throws me off. I checked water tank in attic and there is what looks to me as an expansion pipe going into main water tank. Can't find an expansion tank, seen expansion vessel in hot-press so to me, I think it's closed system and if it is, I never knew it needed an expansion pipe. ill have to double check everything tomorrow.

Expansion pipe going into large cold storage tank? Is that not just the vent pipe from the top of the hot cylinder, if an open vent hot cylinder?
You sometimes get a heating expansion tank fitted in hotpress by plumbers. It is normally red in colour if a heating expansion vessel, although you can't always depend on colour. Would be a very easy job to visually check what system it joins to, - heating (or unvented cylinder).
The unvented cylinders that have external expansion vessels usually have white, or less commonly blue vessels.

 

[soccercelt]

Expansion pipe going into large cold storage tank? Is that not just the vent pipe from the top of the hot cylinder, if an open vent hot cylinder?
You sometimes get a heating expansion tank fitted in hotpress by plumbers. It is normally red in colour if a heating expansion vessel, although you can't always depend on colour. Would be a very easy job to visually check what system it joins to, - heating (or unvented cylinder).
The unvented cylinders that have external expansion vessels usually have white, or less commonly blue vessels.

Yes that's what I was thinking it was. You see, I can't follow the pipe to see exactly where it's going but there's a bent copper 3/4 pipe bent round and into the storage tank. I was of the thought if it was a closed system then it didn't need a vent pipe. There's defo a red round expansion vessel in the hot press. With no expansion tank, a red vessel I naturally thought it's a closed system however when I seen the 3/4 pipe bent into the storage tank and 3/4 pipe coming out of top of cylinder, this is what's confusing me because I always thought closed system didn't need the 3/4 pipe out top of cylinder.

 

[Riley]

Pics buddy

 

[soccercelt]

Pics buddy

I will tomorrow. Have to pop into his house tomorrow so will sort pics then.


Been looking at some diagrams online and what I'm guessing is, basically an open and closed system is the same only the pipe in open system going to expansion tank, it goes to an expansion vessel on a closed system. I might be wrong though

 

[Riley]

But you say it has both

 

[tamz]

Open tank fed domestic and sealed system heating.
All pretty std stuff.

 

[Riley]

You see that's what I thought tamz then I was sure I read white expansion vessel. Maybe I've misread

 

[Best]

Was just sitting drinking wine and about to say same, ^^
Almost certainly a sealed heating system and the vent to cold tank is nothing to do with the heating, but is for the hot cylinder to vent air, in or out and expand water.
Seems the OP isn't a plumber

 

[Best]

You see that's what I thought tamz then I was sure I read white expansion vessel. Maybe I've misread

Sorry. That might have been my post that mentioned white when I tried to rule out if heating vessel. Too much info from me.

 

[tamz]

Was just sitting drinking wine and about to say same,

Just in and cracked a Jura

 

[Ric2013]

Been looking at some diagrams online and what I'm guessing is, basically an open and closed system is the same only the pipe in open system going to expansion tank, it goes to an expansion vessel on a closed system. I might be wrong though

A sealed system is what I think you mean? In this there should be 1. a pressure relief valve (this should discharge to a safe position, normally outside - could yours go into the cold water storage system? (it shouldn't, but...)) , 2. an expansion vessel, and 3. a pressure gauge somewhere, often all three are incorporated into the boiler itself. These are the industry terms, please Google them to check we are in understanding.

These three items replace the open-vented system components: feed-and-expansion cistern, cold feed, and open vent pipe. Other than that the systems are pretty similar, but I'm assuming we're talking about what your talking about, which may be a mistake.

Does the system have a combi (combination) boiler that provides hot water on demand, or is there a copper cylinder in the house?

Can we have a picture of the cylinder please, as I'm assuming that what you have is a traditional vented cylinder, but if it's an unvented cylinder, then it's a potential bomb if plumbed incorrectly.

Are you changing anything or just replacing pipes you have damaged in the process of lifting a floor?

 

[soccercelt]

A sealed system is what I think you mean? In this there should be 1. a pressure relief valve (this should discharge to a safe position, normally outside - could yours go into the cold water storage system? (it shouldn't, but...)) , 2. an expansion vessel, and 3. a pressure gauge somewhere, often all three are incorporated into the boiler itself. These are the industry terms, please Google them to check we are in understanding.

These three items replace the open-vented system components: feed-and-expansion cistern, cold feed, and open vent pipe. Other than that the systems are pretty similar, but I'm assuming we're talking about what your talking about, which may be a mistake.

Does the system have a combi (combination) boiler that provides hot water on demand, or is there a copper cylinder in the house?

Can we have a picture of the cylinder please, as I'm assuming that what you have is a traditional vented cylinder, but if it's an unvented cylinder, then it's a potential bomb if plumbed incorrectly.

Are you changing anything or just replacing pipes you have damaged in the process of lifting a floor?

If it's an unvented cylinder, I won't be going near it. This is the reason for the thread because I know there's a system if plumbed wrong, it can blow up. This is what I meant earlier in the thread when I mentioned a pressurised system.

I'll only be fixing back the damaged pipes, basically all new pipes going to rads from boiler and cylinder. Won't be touching pipes 1meter away from cylinder and boiler that's already plumbed in. I'll also be replacing all got and cold pipes to sinks.

I must stress, Im not a time served plumber but I know how a gravity fed system works. It's just I need to get my head around this system before I start on it. I'm 20 years working on these in my own houses and families. Have also worked with time served plumbers on the open vented gravity fed system.

 

[soccercelt]

Here's pics?

Reason why I'm tackling this is have been let down by 3 plumbers and others can't do it for a few weeks and were under pressure to get it done. Have a plumber might be able to come in during week and both us do it together. Should have it all done in few days. First fix 5 rads, hot&cold to kitchen and bathroom which is right beside hot-press. Electric shower and now maybe move oil burner because it's in the house

 

[soccercelt]

Can a mod please insert my pic. It's saying drop and drag but can't do it on this phone