Air con & Cylinder Wiring | Thomas Nagy 

Hi Tom There should be a two port valve as a safety cut out between the mid position valve and the cylinder as you have seen the when the mid position valve is stuck open there is nothing to stop the water from overheating . There should be a valve supplied with every cylinder they have to come as a full package, plumber has left it out and pocketed it, I’ll guarantee he’s not qualified as an unvented cylinder installer

Isolators are needed by the condensers for us aircon guys, when we are working on them in case of emergency, also pain in the arse having to go back on forth when resetting them during fault finding ha.

Hey Thomas love the videos, its really cool to see how you guys do stuff over there, I'm from the U.S. and we are a little behind you guys when it comes to regulations and sometimes even technology. What a horrible place for those AirCon condensers to be located, I feel bad for the tech that has to clean those, also is that a dryer vent blowing right on the unit? If it is that unit will be covered in lint in no time!

I hate boiler controls especially when someone's had a go but like you said it really sharpens the grey matter tracing the issue. Plus I feel (quite rightly) smug when I find the problem and the client is happy😊

I don’t envy the person who has to change a compressor in one of those condensers 😆

Give PB Plumber a call 😉

Love your vids Tom! Plumbing issue for sure, everyone saying you cant have a 3 port on a unvented cylinder.. you can but if you do you have to fit a 2 port on the flow to the cylinder and wire to the over heat as a saftey. Also fit a bypass valve. Before i forget 3 port or a y plan takes hot water as priority so would heat the cylinder first then go to heating. Thats also why the water is too hot because the valve is acting as a bypass and is really meant for a vented system. Would be easier to make an s plan. Hope this helps.Plumbing on that install is shocking haha

At 14:58 you are so right! Too many walk away from heating, door entry or fire alarms but surely that's where we cross from pullin' cables to a proper all-round electrical technician. wha' do I know - doh!

It could well be a two port valve being required but another point with three port valves, there are two types, Diverter valves and Mid-position valves Diverter valves feed from the leg to either of the tees (but not simultaneously to both) Mid-position valves can feed from the leg to either or both of the tees Plus three port valves can be manually positioned for system filling, if the lever latches then the valve will permanently pass regardless of the actuator position. Finally, a rant of mine, close to 100% of heating and hot water wiring issues could be eliminated and massively decreased in installation time by using logical wiring, with fully defined core colours and terminals. Rats nets wiring with random core and terminal assignment, with sleeves or often not, and not following any standard are what causes problems. Multicore pvc flex with 5 coloured cores or 7 cores with numbered cores wired from a 'Wiring Centre' near the boiler, to another identical one near the tank/valves with 100% identical terminal number assignment makes wiring to boilers, valves and thermostats very fast and easy. It's a pity the standard 'plan' diagrams and the information from boiler manufacturers haven't moved in this direction as they perpetuate the rats nest fully randomised approach.

The wiring difference between USA and across the pond just surprises the heck out of me. It's really interesting to watch and compare how I do things versus how you guys do things

Best episode for a while, true unscripted humour is pure entertainment.

Your final comments were spot on! It really doesn't matter if you haven't done something before, you just have to start ot with the ability to learn

Did you try turning it off and on again ?

Thanks Tom for another classic video... I've had my own issues with S plan (I believe it was called) wiring, orange grey etc... tracing racing stracing every last hair of a flexi cable and having to understand all those valves. I was in Battersea in a posh posh place in Prince of Wales Drive. All I did was label it all up exactly as it had been and put it back, neeeter as it had been. I changed out a broken junction box, the brain, the nerve centre! Well the customer (who didn't use the flat to live in, just to collect his post from!!! - flat worth about £5m) phoned me to say the boiler wasn't working. I had to go back and panic, over two days trying to understand what I'd done wrong. O I made such a meal of it. Ditto your thoughts about being mentally strong for running your own business. So true. I don't know how most people do it. I've always been blessed with a fall back in the Reserve Forces, hence I went away for upto 4 years with them PAYE. Granted, it was often DEADLY dull, NAILS uncomfortable, or a war zone, but it was so much on the whole less stress being looked after by the Armed Forces. I had to retire from them last year, and I'm still feeling my way. Keep them coming, your video release days are always an event for me... I'm sure you won't have gotten to this far down my drivvel but if in case you were to have, any idea what having loads of LIKES does? I mean I'd rather have subscribers, what use are Likes do you know?

In Aussie and NZ the isolator has to near the condensor. Those units should not be their for several reasons. Lack of airflow, in an unservicable position.. more.

With the 3 port valve, have you wired into the hw off terminal in the programer . This will turn the valve so only heating is open. I have only wired up a small number of y plan, but that got me the first time I did one.

I'm so glad that it's not just me that has jobs like that where you can't work out what's going on! Had one today where the Sky Q wasn't getting a good signal via LNB so I fooked about with it for a good few hours until I thought about checking the box, someone had been behind the TV and the connectors were loose as fook, I was really fed up by that point!

Hi Thomas That Air Conditioning will be struggling to work under there...... not enough air onto the back of the condensers and the discharge air off the unit will recirculate back into the air on...... give it a year before it bites the dust,!!!!!

That tank isn’t installed to the current standard. Should either be S plan or as you say the extra 2 port valve fitted.

The instructions you get with motorised valves are worth reading. Think there are two different 3 port valves, a diverter and a mid position if I remember right. Normally the same set of instructions covers all the valves in that range. Excellent videos thanks.

Love working on my own.....finally get chance to have a good old chat to myself without looking weird.

Can’t use a 3 port valve as it’s a safety issue like your finding (against unvented regs for just a 3 port valve ) Needs to be 2 x 2 port valves eg s plan

Hi Thomas. Id say putting the isolator near the condenser is better because most of the breakdowns with these machines is at the condenser. 90% of the time its the capacitor for the compressor that requires changing. These capacitors can range from anything from 35, to 60mF. They can hold a pretty hefty charge and needs a few seconds after switching off the isolator for the capacitor to dissipate its charge. Keep up the good work, thanks foe the vids.....

Hello Thomas you need them beside for servicing safe isolation great content really enjoy!

All the plumbers I worked with when wiring their systems fitted 2 port valves and never 3 port. A little more expensive but generally more reliable and easy to expand to more zones. Also easy to work around when a valve failed (e.g. just manually operate it for 30 minutes). They were also always fitted with isolator valves each side for ease of maintenance.

Very cold willy. Thomas Nagy 2019

Tom "Chilly Willy" Nagy, Should have that on the side of the van.

Sounds like a HW off signal issue. Either from programmer or tank stat it’s connects to the grey cable on the valve. It’s should be energized when HW is off. Three port valves always default priority HW so require a HW off signal to stop tank heating when CH is being demanded. Hope this helps keep up good videos!

Hi Tom, We need isolation at the condenser to ensure power is not reinstated while working on it. Even on simple split systems like the ones you have here, We are being asked to now install fused spurs at the indoor unit too for the same reason. Thanks for the video's, Always enjoy your content and know many HVAC guys do sub to your channel. P.S I hate getting new work gear dirty too!

Tom it may be a mid position valve that is fitted and it should be a diverting one, when on heating only the water does not pass through the cylinder just goes to the rads, when in hot water mode it closes the heating port off and the cylinder stat opens and closes the valve, when the cylinder is up to temperature stat closes the valve and knocks the boiler off. The missing two port valve is a high limit control valve and that works with the other part of the cylinder thermostat and will stop the flow of water from the boiler into the cylinder if it exceeds its setting to stop anyone scalding themselves.

A 2 port valve needs to be fitted after the mid position valve supplying the cylinder side. 👌

A good practice for those systems is to install a couple zone valves. Get yourself a infrared thermostat, for heating faults. It also helps with underfloor heating as well.

one never stops learning chap.

Tom, ignoring the fact that it shouldn’t be a 3port valve, and guessing by the quality of the rest of the installation, I’d say either the valve is fitted the wrong way round or there is some debris (solder etc) blocking the valve shutter and preventing it from closing. Providing it’s wired correctly and the valves operate when they should, I’d call the Plummer back. 👍

The switch next to the air con tends to follow on from similar practices used in industry/factories. Allows local isolation of the machine and also locking the switch/isolator so nobody can turn it on.

I like the new video format. It's more technical with useful information.

You need to move condensers as air flow looks blocked

Aren’t those Daikin units gonna recycle there own air.

Page 24 of the Manual 'The boiler thermostat and thermal cut-out must be wired in series with the 2 port motorised zone valve supplied to interrupt the flow of primary water around the heat exchanger coil when the control temperature has been reached. '. The 2 port is a high limit stat if its not fitted it won't ever work properly.

Hi Tom.going from an install I did on a similar set up u should Def should have a two port fitted in line with the hot water feed behind that 3 port (not your problem tho mate) Although the symptoms your describing would say to me that the s/l from the two stats (cylinder and central heating) are switched around. I’d have the two port valve installed and then start again with a fresh head another day mate it’s only going to be something silly. Done loads of heating wiring and your right what you say nobody wants to touch it - I only did because we had loads of price work and nobody wanted it

Exactly, jump in and get involved. Look through the manual, download some diagrams and try not to make the situation worse! BTW I never get cake you lucky sod ;)

Re the hot water. Ive had this at my own house. It was the 3 port valve at fault. When the heating was being called for, the water flow was also going to the tank and the radiators at the same time. And it doesnt take long for the got water tank to reach about 70c. Like you say, enough to burn your hands when running a tap.

That 3 port valve is a normally mid position and with that cylinder should not be a 3 port valve. Change it to a s plan snd use two 2 port valves.

Try rewiring between hospial floor voids, Hot, dark, dusty, and all sluce runs are in glass fun.

Watching this video upsidedown gives Tom balcony levitation powers

I find I am for ever fixing 3 port valves. I now change them and fit 2 x 2port and never expect to be called back to a valve problem. I currently have one to replace that seized up over the summer through lack of use. I also do not like the design where when the water and heating are turned off the valve is permanently energised. I wonder why they fail.

Tom for a start that unvented hasn’t been fitted to G3 regs. It’s on a y plan should be on an s plan. Without being there, I’d be first calling for heating only, and checking to see if the port that enters into the cylinder is cold as it should be.

@ThomasNagy the three port valve is likley wired incorrectly. Not always, but 3 port valves often have a wires for the following: # Heating On # Hot water off or satisfied / Heating Only # Boiler and Pump # Neutral # Earth

Hi Tom, Im going to say the port valve is shot ! If the tank is getting hot when the heating is on but the hot water is off then defo the valve ! Iv had it where the heating is off but the hot water is on and the rads get hot

depending on the 3-port you might need to link the grey and white together other wise it is in a blending position (this completely depends on the type of valve and if its just a 3 wire)

Great video, I agree, I've only wired 3 central heating systems, but you do pick it up, ounce you get your head round it , it helps if you can understand how the system works. I thought they would have covered some heating wiring in college, but wasn't anything at all. On a different note, I would be careful about that stalker, he doesn't seem all the ticket.

If it's a 3 port or mid position valve you need a 3rd satisfied wire from the cylinder stat to the motorised valve. Should also be a satisfy wire from the dhw off terminal on the programmer (normally terminal 2 on most generic programmers)

If it's a three port valve, there's a connection that tells the system to not heat the water, it'll close off the part of the valve that allows heated water into the cylinder coil. It's usually grey in colour.

Woah those condensers wont be very efficient :S, they usually need a good .4m or more of free space. RIP the person who has to service 'em

Perhaps the valve is set to bypass (used when filling the system)

Glad we got there in the end Tom 👍🏻

It has a 3 port valve on it. New systems are supposed to have a 2 port feeding them for a positive on/off - it's a legal requirement for pressurized cylinders to stop them over heating on new installs. This is why most systems are now two 2 port valves heating/hot water and not a 3 port mid position valve because this exact fault has caused old open vent systems to boil over, the plastic tanks to melt in the roof above and scolding water to flood down over people in bed. I trained first as an electrician on a heating company then a gas engineer so I've seen this many times first hand.

We have an almost antiquated heating system with a three-port (Y-Plan?), and the only options with the programmer are Hot Water, or Central Heating + Hot Water. Not ideal as you can't run the heating separately in that scenario.

Looks like a y plan system to me (3port valve) need a 3 core to the cyl stat. All 3 connections are used.

Just watched your video, Thomas, great job, just a question about the 3 port valve, have you got a satisfied signal from the programmer to the valve, once hot water is satisfied, the valve sends the water through the A port/central heating, that's how I understand 3 ports work, let me know if this info helps, cheers

Check that the valve to the tank is not stuck open, have had that happen on our central heating system, it was new valve as well as the previous one had stuck shut. Might not be the valve itself but the servo motor as they can be obtained individualy so the plumber might have changed the valve and used the old servo motor.

cylinder stat is pooped and two port valve is necessary and has to be fitted as per regulations. its linked to the cylinder stat for overheat protection

yehaaa its Thomas time again

I was in London in a Taxi stopped at Traffic Lights. I was travelling from one Railway Station to another, as you do in London, when another Taxi pulled up along side Me and because I was seated in the Jump Seat behind the Driver and facing Rearwards, I saw who the Passengers were in that other Taxi. Best 60 Seconds of My young Life. I actually got to talk to The Beatles.

I’d suggest to the customer a competent heating engineer is asked to call by to check over and rectify. These things are litteraly like a bomb when they go wrong and can take a house down.

I love boiler wiring,used to get scared of it in my early days, now it’s all in my head, very rarely need a diagram these days.

Poss the valve is knackered or maybe the lever one the end is latched in the fully open position. I would be getting a good G£ qualified plumber to look at that install. It looks like unqualified cowboy install, and if those unvented cyls go wrong without the correct safety devices fitted - it can go off like a bomb. I scalding hot water filled bomb. Thanks for all your quality vids - please keep them coming.

Sounds like the valve is either sticky or faulty. Check that the 3-port has moved over to the heating side when the hot water is off/satisfied, and also check that the grey of the valve is live, as it should be if the hot water is satisfied. Motorised valves are usually the cause of most problems like this. Its bloody dangerous for those cylinders to get too hot as they can explode.

3:50 that's information we really wanted to know / but it made me giggle

Nothing like a voltage logger on that threeway to watch the on off times. Weeks worth of data will tell wonders. Get the customer to jot down steam event times and dates. Cheap thermometer in a cup bidaily while in the kitchen with a time and date stamp should also help. I have caught faulty fridges with a temp logger in the past this way.

I’ve had a lot of trouble with myson valves sticking and doing crazy stuff!!

3:00 and follow minutes How install it so crazy? How they can check the AirCon, repair or change it? Here in Thailand we make a small house around for save them for the weather - but with free space around. The second problem is the air flow for in and out. Behind the thing isn't not many space, and at front looks the air can't go out fully. It is really allowed for the many save regularies in UK to install and work it in that place?

You learn everyday Tom :) central heating wiring can be a bit confusing I learned my side of it through loads of house bashing y plans s plans megaflows etc the micro switches on the diverter valves are prone to sticking or even failing some you can manually spring over by a lever in the side activate that see if it helps if it does valves fcukled also local isolation by the AC units just for maintenance and safety basically not every ac fitter is electrically competent great vid mate looking like your doing well work wise next time put a couple of knee pads in your boxers cold will is averted lolll

I install Daikin products all the time, that install is unacceptable, no idea how that is supposed to work correctly. Why do home owners allow these things to happen? Surely people with a common sense pick up on these things. Good luck to the service engineer when something breaks.

In the States, isolators/disconnects must be within sight and within 50 feet of the equipment.

Tom, I am no plumber (or spark come to that, just enjoy the channel) but I have a similar system in my home. When it was being installed the plumber had to balance the hot water from the tank with cold water to reach the correct temp for hot tap water....so I wonder if this is actually a plumbing issue after all.

2 port valve 100% required mate

I've become too dependent on these videos, waiting an entire week almost kills me

im a plumber tommy... firstly it is a plumbing issue... he has fitted it as a Y plan on a 3 port usualy found on old gravity systems.. they work so you have hot water only or hot water and heating ( it doesnt shut off the hot water side when the heating is on, they are known as mid position valves) when calling for heating.. when calling for heating it still heats the hot water... he needs 2 x 2 port zone valves (Y plan) so you can control the heating separately to the hot water. when call for hot water the hot water zone valve opens and heats the water.. when call for heating only the heating valve opens.. when calling for heating and hot water they both open... hope this makes sense..

We always fitted the isolators next to the condensing units, ie: local disconnect. Not the best place for the units, poor air flow and a pig to work on. Glad I am retired !

Having the lock out switch near the unit is for safety reasons. Means you see it when you go to the unit and remember to lock and tag out. One lock, one life. Safety trumps convenience, most of the time :)

the hot water outflow should be through a TMV to control the temperature at the taps

In America, the disconnecting means have to be within sight of the units. As far as working on my own. I prefer it. People frustrate me when they don't do things to me standard lol. Also, I work pretty hard and fast. People that word slower than me also aggravate me lol. Working by myself gets more work done in most cases.

i quite often have to rectify faults after sparks have been at heating controls, for bigger systems with many zones or boilers i will normally do a wiring diagram myself for the spark to follow, ive got the knowledge of how control systems work but dont have the fingers to be a spark.

It sound like the three port valve is letting by and the central heating water is getting into the cylinder coil when the programmer is only calling for central heating, I would recommend installing a 2 port valve on the flow to the cylinder because it's unvented and the expansion could cause the cylinder to explode. Normally it wouldn't be too dangerous on a vented cylinder as the boiling water would vent into the cold feed tank and the only danger would be the consumer burning themselves when using the heated water but with unvented cylinder it can be extremely dangerous, I would recommend keeping that system switched off until the three port valve has been replaced and it would be best to wire in that extra 2 port valve to prevent this lethal situation happening in future

I reckon that guys got a picture of you over his bed.

Mr. Nagy, I hope you are thinking about doing a podcast. I try to listen you on Fix radio, but a Podcast would be great. Cheers

Thinking about the three-port valve issue, if I read things correctly you'd get these symptoms if the system has been wired up W-plan using the mid-postion valve as diverter and the orange wire isn't being used to switch the boiler on when open. With this if the valve motor fails when CH calls the flow gets passed to the cylinder which then gets heated to boiler flow temp as the 'stat has [no] effect. Shoot me down if I'm wrong.

The air con isolators in mg school are next to the condenser so we turn them off and it makes the teachers flip out

Anyone know the rules on earth rods? I am having trouble getting a good earth connection. I have drove two 6ft rods down in different areas and still failing. I have a 12 foot retaining wall in the garden, what do you think if I put an earth rod in horizontally, the rod would be going out of the property boundaries and into a public lane, but under 8 foot of ground.

Those isolators have to be near the condenser. But should they be outside or inside? I have seen one indoors right on the other side of the wall, where condenser was.

i've seen issues where with the y-plan, if you keep calling for heat when the thermostat cut off, the valve reverts to h/W but the boiler will keep the pump running to cool the heat exchanger. this just keeps topping up the tank with hot water and in affect the tank stat is out of the loop. system runs great during the summer when there is no call for heating.

I will say fitting an isolator in that space is ridiculous. However having it next to the unit means it's fairly certain that that unit is disconnected for maintenance. On one occasion I was at a library doing an outdoor movie and a business nearby had some stuff in an alley and a big gust of wind came through and the doors they had leaning against the wall fell over and hit the air conditioner unit. it start making a really bad grinding noise as it knocked the fan out of alignment and thankfully they did not lock their isolators. so I was able to pull the disconnect and they even had their phone number posted on the outside of the building so I was able to call and leave a message and say what happened. They came in Monday morning they were wondering why it was warm they checked their messages and presumably called their AC repair person.

Prob the valve. The 3port type give a lot of trouble. Safer with two 2 port valves although that’ll need the plumber to fit them. Cause the system will need drained. But in the long term more reliable. Some the older valves where from older heating systems that when the hot water was called it opened up for hot water but when the CH was called it opened up both so that the tank and rads got hot water. That was back in the day before stats where on tanks

You can't have a three port valve on an unvented system, it has to be a two port valve (S plan).

Tom there should be a 2 port , otherwise it will constantly warm up with heating on

Was on a job. Installed four isolators in a boiler house about 5 meters from the units. Better off inside for the person using them however seldom.

Local isolation within 2m for maintenance? That's always been in my mind. Is it a Regulation, I'll have a look Cheers

Sounds like there is port valve not working correctly or missing as you mentioned. As it should switch to pump around heating rather than the hot water tank although my heating system is gravity fed open vented system

3port valve is working ,if ch and hw are on the 3 port valve will allow the heated water both ways that is why there should be a 2 port valve between 3 port valve and cylinder wired via the cylinder stat to shut the 2 port valve when water in cylinder reaches temperature