Mega flow heating system, Electrician needed

[Snoot]

Hi all. I had a Megaflo Heatrae Sadia installed about 4 years ago and it's never run right since it's installation. At this time of year is when i realise it's not working correct. When i turn on the heating manualy for a bit extra heat by the themostat, sometimes it comes on, sometimes it does'nt. I've had the rep from Worcester (Greenstar 30CDi System) out to check everything is ok with the boiler itself and he gave it a thumbs up saying it's not wired in correctly. I'm a builder and I've had two different electricians here who are our usual contractors but to be honest, i don't think they have a lot of experience with this kind of system. It was setup in the beginning to have upstairs and downstairs on seperate wireless thermostats, but since we couldn't get this working correctly i told them just to put it all on one thermostat. It's still not working right. As a bricklayer by trade, it's all a bit complicated to me... but it seems to be because it has 3 port valves which seems to be causeing problems for the sparkies i know.

Anyway, I'm looking for an electrician (Durham area)who is experienced with these systems to have a go and see if they can get it running correctly once and for all. Or if anyone knows where i can get hold of a wireing diagram for the electricians for a 3 port valve system.

Many Thanks

Mark.

 

[holmslaw]

..

 

[londonboy]

http://i22.tinypic.com/2ib1ekh.jpg

That is a rough wiring diagram, but needs to be altered slightly to allow for the wireless stat. Do you also have a 2 port valve beside the megaflow?

Shame your so far away, I do this almost every day

 

[electronicsuk]

When i turn on the heating manualy for a bit extra heat by the themostat, sometimes it comes on, sometimes it does'nt.

I realise this might be obvious to you, but is there a timer anywhere in the system? If there is a timer/programmer, the heating will only come on during the programmed times, regardless of the position on the thermostat.

I'm a builder and I've had two different electricians here who are our usual contractors but to be honest, i don't think they have a lot of experience with this kind of system.

As already mentioned, not many electricians do understand heating controls wiring. I can't understand why, because it's not complicated, and some plumbers don't seem to understand it either.

It was setup in the beginning to have upstairs and downstairs on seperate wireless thermostats, but since we couldn't get this working correctly i told them just to put it all on one thermostat. It's still not working right. As a bricklayer by trade, it's all a bit complicated to me... but it seems to be because it has 3 port valves which seems to be causeing problems for the sparkies i know.

How many 3-port valves are there? It sounds like a Y plan system, where the valve can divert the flow of water to either the CH, HW cylinder, or both in the mid position.

However, you also mention that the system was originally meant to have two zones - if this is the case, then there should be no need for a 3-port valve. Instead, there should be 3x 2 port valve, two for the heating zones, and another for the HW, wired as an S-plan system.

Anyway, I'm looking for an electrician (Durham area)who is experienced with these systems to have a go and see if they can get it running correctly once and for all. Or if anyone knows where i can get hold of a wireing diagram for the electricians for a 3 port valve system.

Don't waste your time. If the electrician doesn't understand what is effectively a simple heating control system, no amount of diagrams are likely to help.

If you post a picture of the airing cupboard and any controls/programmers then we might be able to help, although on this occasion I do agree that you might get a better response in the plumbing forum.

 

[londonboy]

Oops I forgot about the upstairs/downstairs zones.

So you have a 3 port, you should have another safety valve beside cylinder, and possibly another 2 port for the 2nd zone.
It would be easier if your plumber had fitted 3x two ports:
hw, upstairs and downstairs.

 

[Taylortwocities]

You will probably have more luck asking in the plumbing forum. You might think it strange, but most sparks don't get involved in water system electrics.

Well I jolly well do, too! I can't even get to the local shops right now, let alone where you are.

Per the above, you'd need to know what plan the system is wired to. Then its detective work with a multimeter.

Edit: I just used google. try doing this:
durham electrician heating systems


Theres a few specialist guys near you.

 

[Click-Sure]

Again, it a shame your so far away, I consider heating controls one of my specialisms, not had one beat me yet!

 

[Snoot]

Thank you all for your help. The system was on a downstairs/upstairs originaly with Drayton Digistat RF2 and digistat SCR and another to controll the upstairs. As i say, the plumber himself took out the upstairs stat so i could get some heat on because it wasn't working. Another problem is that i sometimes ... allthrough rarely... the water will go cold. My plumber told me the water is suposed to be constantly heated and i shouldn't be getting cold water at all... again, not sure about this as i don't have a clue myself. I'm going to have to find someone once i get christmas out of the way.
I'll post some pictures out of curiosity so you can see what you think. Thanks very much again. Mark.

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• Snoot
• 23 Dec 2009
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• Snoot
• 23 Dec 2009
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• Snoot
• 23 Dec 2009
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[Taylortwocities]

I'm assuming the "Tank stat" connection is the thermal cut-out of the Megaflo?

It is very important that this is wired in series with the DHW control circuit so the Megaflo doesn't boil if things go wrong.

 

[electronicsuk]

I haven't had time to take a proper look over the picture of the wiring centre yet, but I would suggest you employ the services of a much better electrician. That single insulated neutral between the wiring centre and the digistat (that looks to have been stripped from a piece of T+E) should not be there, and wouldn't be acceptable under any circumstances without being enclosed in conduit or trunking. Looks a bit of a lashup that is rather typical of builder's contractors, I'm afraid.

EDIT: Sadly it's a bit too difficult to follow the wiring in the pictures, due to the way everything has just been stuffed into the box. We can say for sure that you don't have any 3-port valves, though - all those in the picture are 2-port. As they are three of them, it suggests that it should indeed still be possible to get the system working as it was originally intended with multiple heating zones. You just need a more competent electrician.

 

[Snoot]

I'm assuming the "Tank stat" connection is the thermal cut-out of the Megaflo?

Well i hope your right then... It does lead to a box at the base of the Megaflo.

That single insulated neutral between the wiring centre and the digistat (that looks to have been stripped from a piece of T+E) should not be there. Looks a bit of a lashup TBH

Well, i think that may of been the plumbers doing after the electrician failed to resolve the problems. The plumber and his mate were at it for ages just trying to get me some heat this time last year. It was supposed to be tempory

Thing is, it's when the cold weather comes like now that you realise that it's not working like it should be. Like tonight, the radiators were cold.... so i added a couple of extra hours on the timer so it goes off at 10pm. still no heat. I have to turn the boiler on and off and let it run through the test proceedure before it will fire up.

It looks like i'm just going to have to bite the bullit and pay for a competent electrician as you say electronicsuk. The electricians we contract in did my whole house at very little cost because it was for myself but as i said, it was something that out of about 6 of them, none of them had installed before. So considering it was pretty much a big favour them having a go, and they have been back and forth at no charge loads of times.... I'm not in a position to tell them they're incompitent....lol.

Thanks, Mark.

 

[electronicsuk]

Thing is, it's when the cold weather comes like now that you realise that it's not working like it should be. Like tonight, the radiators were cold.... so i added a couple of extra hours on the timer so it goes off at 10pm. still no heat. I have to turn the boiler on and off and let it run through the test proceedure before it will fire up.

What you describe there sounds potentially like it could be a boiler fault. If there was no call for heat, the boiler would not fire at all beyond its startup test procedure. After you turn the boiler off/on, does it continue to provide heat until the timer clicks off?

Of course, a good electrician will be able to put a meter on the boiler and check that the system is calling for heat when it should be, and not when it shouldn't be. If you ask for a record of the testing then you'll have some evidence to fire at Worcester Bosch if it does transpire to be a boiler fault.

 

[julioarca]

Hi Snoot, I live in Bishop Auckland, I would be happy to lend a hand in sorting this for you, recently wired a system in a house, 3 x port valves and 3 stats..David

Do I see only 1 wireless receiver, this must be 2 channel then to distinguish between up and downstairs or is there another receiver to connect in.

Just thinking out loud so guys please correct me....

so the boiler has a permanent 240v feed

There are 3 x 2 way port valves, 2 x wireless stats and a cylinder stat

one valve is downstairs, one is upstairs and the other is feed to tank hotwater

all 3 orange wires from the 3 port valves are joined together and go in with the feed into the boiler which calls for demand and ignites the flame

all greys together too and they get a pernament live feed

So one wireless stat needs wired to its correct valve for down stairs
and one for upstairs
and one for hotwater

So the switched live return (call for heat) from say the down stat goes to the brown for the correct port valve for downstairs plumbing circuit

same for upstairs

and same for hotwater

Then simply when any stat calls for heat, valve is opened and supply is given to boiler for it to ignite, if all 3 stats call for heat then all 3 valves will be open an pumped hotwater is shared between them until each stat reached set temp and then they stop calling for heat thus closing the valve and well thats it

any good guys?

 

[electronicsuk]

Do I see only 1 wireless receiver, this must be 2 channel then to distinguish between up and downstairs or is there another receiver to connect in.

See OP. Due to the system never working as advertised, it has apparently been converted to run as a single heating zone from one stat.

so the boiler has a permanent 240v feed

Presumably, judging by the fact that there look to be two flexes going to it.

There are 3 x 2 way port valves, 2 x wireless stats and a cylinder stat

Only one stat right now.

one valve is downstairs, one is upstairs and the other is feed to tank hotwater

Presumably.

all 3 orange wires from the 3 port valves are joined together and go in with the feed into the boiler which calls for demand and ignites the flame

all greys together too and they get a pernament live feed

Again, presumably, although if this were all wired correct then you would expect it to be working, unless it's not the wiring at fault.

So one wireless stat needs wired to its correct valve for down stairs
and one for upstairs
and one for hotwater

So the switched live return (call for heat) from say the down stat goes to the brown for the correct port valve for downstairs plumbing circuit

same for upstairs

and same for hotwater

Sounds reasonable, although I'm not sure how the HW stat is working in this installation - I'm not familiar with Drayton's range of RF stats, or any RF stats at all for that matter as I consider them a poor solution to a problem that doesn't really exist.

That aside, I assume one of these RF units must be a combined timer/programmer to control the hot water, as it wouldn't want to be permanently controlled by a cylinder stat alone. Depending on whether or not the upstairs RF stat also contained a timer (back when it was wired in) will also have some bearing on the situation, as if it doesn't contain a timer, it will need to come on/off with the main CH programmer output. You'd need to look at the documentation for the Drayton products in question.

Then simply when any stat calls for heat, valve is opened and supply is given to boiler for it to ignite, if all 3 stats call for heat then all 3 valves will be open an pumped hotwater is shared between them until each stat reached set temp and then they stop calling for heat thus closing the valve and well thats it

any good guys?

That's the jist of it.

 

[Snoot]

Thanks David.... that's what i was hopeing to hear from someone I would rather it was back on a upstairs/downstairs set up anyway. I've noticed this morning that downstairs is calling for heat, but i'm asuming none of the valves are opening. The manual pump lever on them should be loose and free when they're open i'm guessing. An engineer from Worcester came out in the first year and tested the boiler was functioning properly and said it was electrical.... so i'm hopeing nothing has changed in that time. I wouldn't care, he left his mobile number so he could talk to the electrician i use and tell him how to wire it correctly. the electrician said he didn't need it as he knew a guy who fits these systems all the time.... then he let me down.

Anyway David, i'll add to friends and send you some details by PM. Many Thanks. Mark.