At my wits end with this heating system PLEASE HELP!

[iateyoubutler]

What's the issue Chap?

I made some good progress, ran (almost) a new hot water return right back to the boiler, and to go belt and braces I decided to put a 2 port valve on the heating return, so there is absolutely no way that it can backfeed through the heating system. I`ve re-piped the bathroom radiator to make room for the new pipework.

But, the pipes won`t solder. I`m using Yorkshire fittings, everything is spotlessly clean, fluxed etc, everything to the letter. I tried 2 joints, heated, and heated, and heated - nothing, just damaged copper

Don`t know what I`m doing wrong, but time to get my trusty gas/heating engineer in to bale me out - he`ll probably tell me where to go haha, and I don`t blame him

 

[polesapart]

If you're new to soldering I'd suggest trying it out on short lengths of copper in the garage first. It's quite satisfying to see the bright silvery ring appearing at the end of fitting for the first time.


Any residual water creeping back along the pipework will b*gger things up - might be what's happened here.

 

[iateyoubutler]

I did exactly that yesterday, and it worked really well which is why I was confident that things would be ok. I couldn`t see any water lurking, if that`s the issue how is that overcome?

I`m tired of it today to be honest, those that do it for a living deserve a medal

 

[Hugh Jaleak]

Not sure what you mean by a 2 port valve, a Non Return Valve would be what you need. (Make sure it's the right way round! ) Edit, just seen it, I'd swap it out for a NRV and remove that dip in the pipework, that could be a recipe for further problems....

Only way to overcome the issue is to get the water out the pipework, if it's getting in at a certain point, then leave that disconnected, solder the rest and worst case scenario, use a compression fitting on the wet part.

 

[iateyoubutler]

Evening all I did admit defeat with this and contacted my friendly boiler engineer. Expecting him to tell me to do one, he was more than happy to come and have a look at my mess, and help out!

In 4 hours it was all sorted, refilled, and working again, and far, far better than it was before. I can also sleep easy knowing that nothing is leaking.

Thankyou all though for the help and advice, as I said, I`ve never soldered pipes before, so a lesson learned - start on a smaller project!

 

[MeldrewsMate]

When the boiler was fitted it was literally a straight swap

I doubt that very much, else you would have had an Ideal Concorde still (that's just me reacting to 'literally'. Now let's deal with the heating problem).

Your new German boiler (shame on you!) will have a much higher hydraulic resistance than your old Concorde, thus the likelihood of creating a 'suck-down' of air into your system will be greater. The 'U' shaped cold feed immediately below the pump may be partially blocked, exacerbating the problem.

I suggest you turn the pump speed down to minimum and see if the problem goes away. If it does, then re-start the heating at low speed, then increase the speed to 2 whilst it is running, then to speed 3. If you can do that without precipitating the noises you complain of, then retry but start the system on speed 2.
With a 15kW boiler you shouldn't need speed 3, and could usually get away with speed 1 if the system is clean and properly balanced.

Coming back to the tests above, if the suck-down occurs with any pump speed then it is likely the feed pipe is blocked.
Does a magnet stick to the copper pipe close to its junction with the main pipework?
If it's blocked then surgery is the answer. Cut out the 'U' section, clear the tee, and replace with new, preferably with a cold feed full bore isolator installed so you can more easily clear the pipework the next time it blocks!

MM

 

[iateyoubutler]

Well, after a week of trying this out it`s working pretty well. When the hot water is on the radiators are stone cold, so a result on that front. I would say that 90% of the air noise is gone, and the hot water doesn`t wake me up in the middle of the night any more.

I`ve turned the pump speed down to 1, because strangely that`s where everything is at it`s quietest, the boiler is kettling slightly, but it does it far more if I speed the pump up (don`t understand that??). Having tried the central heating on the slow pump speed, there is no difference to how it was before. Al seems good.......

 

[MeldrewsMate]

Well, after a week of trying this out it`s working pretty well....

Glad to hear that, but no mention of that magnet sticking to the copper pipework on the cold feed 'u' bend?

There is an instruction on this site which will help with system balancing; that should be your next move once you're satisfied the system is clear and clean.

 

[iateyoubutler]

Glad to hear that, but no mention of that magnet sticking to the copper pipework on the cold feed 'u' bend?

There is an instruction on this site which will help with system balancing; that should be your next move once you're satisfied the system is clear and clean.

That was removed and replaced when the pipework re-designed in the cupboard

 

[Hugh Jaleak]

Think the general consensus is to have the pump on the lowest speed the system will operate effectively at. If it's happy on 1 and everything is working, leave it there. (Old adage, 'If it works dont fix it.')

 

[iateyoubutler]

Think the general consensus is to have the pump on the lowest speed the system will operate effectively at. If it's happy on 1 and everything is working, leave it there. (Old adage, 'If it works dont fix it.')

Strange, with the system as it was before, it would never work very well on the low setting - the boiler would keep overheating and locking out, it would only work on 3. Now, it just purrs away quietly down on one. If I speed it up all hell seems to break loose! So yes, it`s not broken and I`m not going to fix it

 

[Gasguru]

It's a Vaillant, the flow and return temps versus burner input are closely monitored...and being German is problematic.
You're looking for a 10 to 20 degree difference under all operating conditions...wander from that and the software will complain.
Don't be tempted to turn down too many TRVs...you need a good flow through the heat exchanger hence the requirement to have an auto bypass valve (set appropriately).
I suspect speed 1 won't be sufficient once the cold weather is upon us...

 

[iateyoubutler]

It's a Vaillant, the flow and return temps versus burner input are closely monitored...and being German is problematic.
You're looking for a 10 to 20 degree difference under all operating conditions...wander from that and the software will complain.
Don't be tempted to turn down too many TRVs...you need a good flow through the heat exchanger hence the requirement to have an auto bypass valve (set appropriately).
I suspect speed 1 won't be sufficient once the cold weather is upon us...

That has been my main gripe about it over the years, it faffs around too much. To be honest I`m thinking of binning it, but then I suppose they are all very finicky now and too clever for their own good? What happened to the bog standard thermostat?!! I wish I had stuck with the original boiler now, none of this trouble!

 

[iateyoubutler]

Are there any that are basic/simple in operation thesedays?

 

[Nige F]

I`m tired of it today to be honest, those that do it for a living deserve a medal

Yes, we get a putty medal when we retire. C O R G I and Gas Safe get a brass one