Advice needed - 10mm system conversion?

[1animal1]

Hi, I would like to pick some of the experts brains on here if I may :wacko:

I have just moved into a 2 floor, 4 bedroom house with a hot water cylinder system (with central heating pump in line), fed by a coil from the boiler and immersion in reserve (Honeywell wall mounted device controls both water and heating separately with a further central heating stat located in the hall). The central heating system is made up of 5 medium sized (1 large) radiators downstairs and 6 small/mediums upstairs, mostly fed by 10mm pipes which look awful! The boiler is the original 1985? boiler which seems to work ok for now.

Looking into systems i think that an unvented system will be the way forward in the future - the mains appears strong (not measured yet but pretty certain it'll be good for the unvented), a combi just causes too much issue especially when I'm cleaning the car and she's showering! We also have a very low pressure mains fed stat shower in the en suite which is virtually unusable due to rubbish pressure (no pump), currently using the electric shower in the main bathroom which is likely to stay as a back up once the install is done eventually (currently paying for a wedding so can't really afford yet). The new cylinder would be fitted in the integrated garage meaning that i could use the airing cupboard to create a double shower in my en suite.

1) My main problem now is what to do about these 10mm pipes which are unsightly and frankly, I can't see how they can be as good as the 15mm - I've pulled apart the cloakroom to refit and thinking that whilst it's all apart, I might as well chase the 10mm to see where the 15mm starts and then speedfit it with new 15mm to the rad, channeling the pipes into the wall from the floor through a feeder box, then 2x 90 degree elbows behind the radiator (as the 15mm pipe will obviously be less flexible than 10mm) to the valves (assuming the rads are 15mm connections) - probably running copper from the elbows for the small amount of pipe that can be seen under the valves. Can anyone see an issue with this? I ask as i believe that new systems run through the first floor and drop to the ground floor rads and lift for the 1st floor rads... and didn't know if this was a lot more efficient.

2) As I'm used to a combi with a filling loop. Something i want to find before i start isolating radiators is how to drain down. From reading i assume i tie up the valve on the header tank and then continue to drain the rads via the normal method with the boiler turned off (pilot out) - or if working the hot water, run the hot taps to empty the cylinder...

3) The flange to the central heating pump appears to be leaking - So what is the best method of attack for addressing this leak, try cleaning the joint and tightening first? then drain down and clean or replace as necessary - it's the large bolt beneath the pump

4) Another small leak is on the lower joint of the cylinder which is white and crusty, should i do the same with this or remove it and clean up after isolating and draining the cylinder?

Any help on the above points is greatly appreciated (I'll try and post pics of the leaks too as assume it could mean a new cylinder depending on the joint) - I figure that whilst the rooms are coming apart then i can do subtle upgrades until the large upgrade happens. After the cloakroom I'll be hitting the living room which has 2 medium rads both with 10mm pipework, the room will also be plastered in the next 6 weeks so would look to do the same with that room too.

Thanks in advance

Tim

 

[Soulman]

I think i understand what your saying so i'll try and help:

1. As you got an old system, it will need a good flushing out. That should be your 1st priority, i understand you want to alter your 10mm to 15mm which will help with flow. However you do realise that the plastic 15mm fittings are quite bulky and will be a pain to chase into the walls. Which is what i think you mean by channelling. You can buy 10mm plastic fittings and pipe which would be much easier to chase into the wall.

Rads come with a standard 1/2inch connection. so you can put either a 15mm trv and lockshield set on or you can have a 10mm set.

Typically you run a 22mm main flow and return through the house on the 1st floor and branch off in 15mm to rads up and down .


2. You should have 2 tanks in your loft, 1 small 1 big. Big tank feeds the cold water to the hot water cylinder. The small tank feed water around your radiators, cylinder coil and boiler. To drain down you need to isolate the water going into this small tank. Then when your ready to fill back up let the tank fill on its own and bleed your rads as normal. Although be careful for air locks.

3. whilst draining down i'd then look at this, either pick up a new set of pump valves or clean and re washer it.

4. The leak your describing sounds like the cold feed from the tank in the loft that goes into the bottom of your cylinder. It would be best to drain the tank and reseal or replace depending on the condition of the fitting.

If your planning on going unvented in the future, and your going to replace some of the pipework, then you might want to look into replacing the boiler for a system boiler. But this is something you'll be able to discus with your installer at the time.

Hopefully thats helped, if ive understood correctly!

 

[1animal1]

That's brilliant, thanks Soulman - much appreciated.

1) I had come across the 10mm pipes being fed into the walls but assumed with the lower ID of speedfit 10mm pipe, then I'd be still with a less efficient system? My walls where these rads sit are 3 plasterboard thick so should be easy to pull channel with either I imagine... do you think I'd get any benefit at all by increasing to 15mm? I was thinking that they'd warm up quicker due to the increased flow...

I'll have to check to see how the pipework is configured as I pull the house apart... yet to lift a floor board

2)I'll give that a go tonight as it was bugging me knowing the water won't have been changed for some time - still to locate the drain valve but i haven't checked all the ground floor rads for this yet.

3)Are these valves readily available from the likes of screwfix? I ask as I have one very local to me and would prefer to walk in with the part in hand. My only other consideration is if there is a copper collar on the pipe join preventing me removing the nut, or will it be a different type of join?

4)I'll do the same for this as the above - I had read that it was important to release the cylinder drain first before releasing the hot taps, is this correct? Also i gather the method for cleaning the joints is to wire wool, emery paper them etc then reseal?

Regards the system boiler - the only reason I hadn't considered a change yet is that i only put it on for ten mins to warm the water up for the dishes, it then remains hot all day - obviously winter use will see it being used a lot more for the rads. The people we bought off say that their plumbers said to keep it as long as possible as it was easy to repair and find parts for cheaply - I'll get the model later to update the thread.

Apologies for the amateur questions - As said, I am used to the sealed simple combi system which seems so much easier to understand

Thanks

Tim

 

[1animal1]

PS Haven't i already got a system boiler?

Edit : ignore me, I've just read the differences which it seems will give me my closed loop back and rid me of one tank in the loft

Are the costs of these high? fitted...

 

[Soulman]

No probs,

1. you can upgrade to 15mm and it will give increased flow to the rads. I,ve ran all my rads in my house with a 22mm main flow and return, 15mm branches and 10mm into the rads. Mine heat up just fine, but mines a combi. Yours being open vented at the moment would be better with 15mm as this would help prevent the black sludge from blocking the pipes.

3. Yes you can get theres from screwfix Gate Pump Valve 22mm | Motorised Valves | NoLinkingToThis Not sure what you mean by copper collar. Photo would help.

4. you need to isolate the cold feed to the cylinder. Should be a gate valve on that pipe. Although if its not been used its probably seized. If thats the case you'll need to drain the bigger tank and replace the gate valve. Yes thats right, and if its a threaded joint you'll need to remove the old ptfe from the threads.

Remember you'll need to add inhibitor when you fill the system back up. But test it first with just cold water to check for leaks. To add the inhibitor just put it in the small tank when your filling up the system.

System boiler was just a thought, if there's nothing wrong with what you've got for now then keep it going. However when you have the unvented fitted you'll need to alter some controls depending on how your system has been designed. But like i say, you can cross that bridge when you come to it.

 

[1animal1]

Brilliant - I'm shooting off home now to attempt. Will update later hopefully.

4) I do remember two gate valves above the cylinder, hopefully they'll still work.

Inhibitor - that's far easier than the last system! I had to buy all the niggly bits to get a bottle emptied into a rad directly

We may consider the system boiler as it looks a lot more efficient and will save a huge bill come unvented installation day...

I'll hopefully be back later with pics if my internet is finally back on (only moved in 2 weeks ago)

Fingers crossed

 

[1animal1]

OK, update... I'm not 100% what the pipe is that's leaking at the bottom of the cylinder, and consequently not sure if it's the hot water system or the central heating.

Secondly none of my rads have a drain valve, the only drains I can find are on the cylinder and above the stopcock on the ground floor.

I'll try and post some pictures

 

[Jimbobber]

If your 10mm tails run back to manifolds then you could be in for more pipework than you bargained for. Also as Soul man pointed out, you would spend considerable time and money chasing out and making good to fit 15mm tails. If you live in an energy efficient new build house with small rads there's no real need for 15mm tails. 10mm is pretty rubbish but at least less invasive and more efficient in a modern system.

Personally I would not bother with a system boiler. I prefer separate components because they will be cheaper to service/replace etc in the long run and if your not GSR you can't mess with a boiler so that blows self maintenance well out of the question. And expensive boiler specific parts etc. Would be great for your plumber but not for you lol

 

[1animal1]

Thanks Jim... The original plan was to possibly use the existing boiler with the unvented cylinder. I've done lots of reading and found that the efficiency difference isn't necessarily night and day, enough to offset the cost of the new system boiler. What's your thoughts on this regards running costs?

I'll have to lift the boards to see what I have... That said if it is worth my while keeping the 10mm then that'll provide an easier install when wall chasing. I'll make a decision once I've seen under the boards.

Tried uploading some pictures but it won't let me post a URL or a JPEG from my phone. Will try again tomorrow

For ref the house was built in 1986

 

[Jimbobber]

Efficiency is mostly down to your homes insulation and heat losses, also the type of system ie having appropriate controls for heating/hot water and using it efficiently. The last thing I'd consider important is 3% improved efficiency with a Worcester boiler over an ideal or a sealed system as opposed to vented. Although unvented systems are obviously now the desired standard.

 

[1animal1]

Ah I'm in the realms of sorting the efficiency, currently E rated. Looking at solar, garage door seals, loft insulation and I've doubled up on the cylinder insulation... Also sealed the loft hatches and laden them with the compressed insulation boards.

My boiler is a Stelrad ideal wlx RS50? Does anyone recognise this or know anything about it, I believe it's original

 

[ShaunCorbs]

http://letsfixit.co.uk/wp-content/uploads/WLx-RS50-60.pdf

 

[1animal1]

Thanks Shaun, that's a lot better than the brown copy I have

Any opinions?

 

[1animal1]

 

[1animal1]

As you guys can see, the gate pump valve that Soul pointed out is shot - only leaking when heating up or cool. My only concern is the state of the pipe when i remove it as there's not much i can do if some needs cutting down if the compression collar has seized on, any tips?.... also I may struggle getting the valve out if the pump is too rigid.

And in the distance you can see the leaking pipe at the bottom of the cylinder - I think upon further inspection that this is a return for the coil in the cylinder and so on the central heating loop - would you still drain the hot water too before touching this?

I also need help with the central heating drain - as said above, i do not have one on any rad at all, the only 2 i can find are on the cylinder and just above the mains stopcock. There's one rad downstairs already fitted with 15mm so it may be worth attaching a drain valve on there once I've figured out how to drain it all.

and finally I'm nipping out at lunch to buy a few bits, that gate valve and anything else for the job - what do you suggest to remove the white crusty corrosion and the blue/green slimey stuff?

 

[1animal1]

I'm probably in danger of droning on with this thread - I've bought the gate valve for the pump, some paste to help seal the olive joint, a valve for one of the lower rads with integrated drain and some inhibitor which I'll put in in a few weeks as a lot of the rads will be coming off in the interim.

The one thing I've missed is emery paper but i assume I'll get away with using wet n dry to clean the joints... Plan is to clean up the joints with wire wool before removing and finishing with the wet n dry. Hopefully this will do what i need it to.

Thank to everyone for their advice so far - wish me luck.

Tim

 

[ShaunCorbs]

I'm probably in danger of droning on with this thread - I've bought the gate valve for the pump, some paste to help seal the olive joint, a valve for one of the lower rads with integrated drain and some inhibitor which I'll put in in a few weeks as a lot of the rads will be coming off in the interim.

The one thing I've missed is emery paper but i assume I'll get away with using wet n dry to clean the joints... Plan is to clean up the joints with wire wool before removing and finishing with the wet n dry. Hopefully this will do what i need it to.

Thank to everyone for their advice so far - wish me luck.

Tim

unless your soldering or the pipe is full of paint you will be fine using nothing/cleaning on the pipe if its just comp joints

 

[1animal1]

I think i'll need them all if you can see the state of my two leaks on the last page?

 

[ShaunCorbs]

I think i'll need them all if you can see the state of my two leaks on the last page?

most of that should come off with a damp cloth tbh

 

[1animal1]

cheers Shaun, I'll give that a go first... the white is very crusty and the greeny/blue corrosion is very oily/sticky so assumed I'd have to use white spirit and wire wool etc...

I can't work out why there's splashes of this green stuff on top of the pipes though - baffled

 

[ShaunCorbs]

cheers Shaun, I'll give that a go first... the white is very crusty and the greeny/blue corrosion is very oily/sticky so assumed I'd have to use white spirit and wire wool etc...

I can't work out why there's splashes of this green stuff on top of the pipes though - baffled

its flux from where they dont wipe the joints you might need warm water yo take that off

 

[doitmyself]

Looking into systems i think that an unvented system will be the way forward in the future - the mains appears strong (not measured yet but pretty certain it'll be good for the unvented), a combi just causes too much issue especially when I'm cleaning the car and she's showering! We also have a very low pressure mains fed stat shower in the en suite which is virtually unusable due to rubbish pressure

Those two statements are contradictory.

As for a combi being no good while, by implication, an unvented cylinder will be OK, that, to put it mildly, is not true. Both are mains fed, so you will have exactly the same problem cleaning the car while she is showering whichever method you use.

You need to check the incoming flow rate and pressure before making a decision. It's easy to do.

If you have a garden tap (normally fed from the mains - check first), measure the flow rate using a marked bucket and watch.

Now repeat (at garden tap) with the kitchen cold tap turned on fully at the same time.

If there is no mains fed garden tap, just do it at the kitchen tap; but be aware that some taps restrict the water flow, which is why the garden tap is preferred.

You need a minimum flow of 20 litres/min for an unvented or a combi.

How well is the house insulated? Double glazing? Cavity walls? Loft? You can get grants for walls and lofts - check out your gas/ electricity supplier.

 

[Jimbobber]

No sorry but you can't compare a combination boiler with a pressurised cylinder. You are right that you need ample pressure to make unvented systems give good performance. At least 3 bar is OK.

A combination boiler provides instantaneous hot water and in no way can be compared to the performance of an unvented cylinder. Completely different systems.

 

[doitmyself]

No sorry but you can't compare a combination boiler with a pressurised cylinder. You are right that you need ample pressure to make unvented systems give good performance. At least 3 bar is OK.

A combination boiler provides instantaneous hot water and in no way can be compared to the performance of an unvented cylinder. Completely different systems.

Both systems rely on the mains pressure to push the water out of the tap. The only difference is that the unvented cylinder acts as source of hot water in the path between the mains input and the tap, so the water does not have to be heated instantaneously.

If you have five litres/min from the mains, you will get five litres/min coming out of the tap irrespective of which system you have.

Pressure and flow rate are not the same thing.

 

[ShaunCorbs]

Both systems rely on the mains pressure to push the water out of the tap. The only difference is that the unvented cylinder acts as source of hot water in the path between the mains input and the tap, so the water does not have to be heated instantaneously.

If you have five litres/min from the mains, you will get five litres/min coming out of the tap irrespective of which system you have.

Pressure and flow rate are not the same thing.

but the question is why will an unvented do more than one bathroom decent and a combi will not (note this is not a question)