Heating Won't Come On

[duffbeerdaddy]

Hi,

A bit of a long story, but I'll try to be brief.

My father passed away earlier this year and I have been dealing with his estate/house etc. acting as executor.

Recently discovered that boiler won't fire up / come on with call for heat, but will with call for H/W.

Immediately thought that the actuator was broken on 3 way valve, or burnt out due to seized valve.

Drained system and fitted whole new valve (I say new, but it was used  from ebay) as original didn't have removeable actuator.

Refilled and tested, but same issue. Thought that it might just be bad luck that this one was also faulty.

Bought a brand new actuator/valve from Wickes. Drained system, fitted and refilled. Same problem.

I think I have now ruled out the actuator/valve being at fault but am stumped as to what the problem could be.

I can hear a 'click-click-click-click' on the actuator (as I did on the first replacement) when I put a call for heat on on the programmer, but this stops when I turn the room stat down. It is as if it is getting simultaneous calls to turn on/off???

I have tried, to the best of my ability, to check the wiring of the whole system against a wiring diagram and all looks to be in order.

I am now absolutely stumped. I'm trying to avoid having to call anyone out, as I am trying to act in the best interest of the estate and save some costs for all beneficiaries by doing it myself. False economy perhaps, as it's already set me back £80.

Could it be the programmer at fault??

Any help or advice would be very gratefully received!

 

[batty]

Honeywell do a fault finding in there wiring guides not sure if this will help but may.

welcome to the forum.

Wiring-Guide-Issue-16 (2)

If you put that link in search it should get you into right place. 

 

[duffbeerdaddy]

Thanks, I'll give it a go. Cheers for the link.

 

[OnOff]

What set up have you got, 1 programmer, 1 3-port valve, a room stat and cylinder stat?

Is the new valve lever on AUTO?

Have you checked your room thermostat? i.e. that when it "calls" (you turn it and the light on it comes on) for heat to the 3-port............white wire at a guess.

 

[duffbeerdaddy]

Hi, Yes - 1 programmer, 1 room stat, 1 cylinder stat, 1 3 port valve and 1 BIG headache...

Lever is on auto.

Room stat is old (not digital), but can hear the click to indicate call - have check common and switch lives at both the junction box and room stat terminals.

Yes the white wire from valve is CH on, as I understand it. 5 wires in total - G/Y (earth), B (neutral), W (C/H on), O (switch live) & Gr (water off). Is this right??

Only thing I forgot to mention in my original post is that in the junction box there are two random wires terminated to nothing:

One appears to be main Live (red), coming from three core cable on which (installer?) has labelled L.E.N., but carries no current at any time when testing???

One wire (blue) coming from programmer feed. Everything else I have checked against a wiring guide, but can't seem to find homes for these two. Puzzled...

Thanks to batty for the link. Wiring diagrams are the ones I was working off, but additional info on PDF was very helpful. Cheers!

 

[OnOff]

Can you take a couple of decent photos of the wiring centre and post them?

 

[Steve3948]

So is anything connected to Hot Water Off in Programmer ?

 

[batty]

The spare wires may just be spares. When I wire heating systems I tend to put a few extra cables in just in case. Sparks are not like plumbers we don't use Green/ yellow for live cables.

 

[duffbeerdaddy]

Onoff - I can take photos and post, but won't get back to the house for a few days because of work commitments.

Hi, Steve - all wiring seems to be in place, but don't know how to check how most of it in the back of programmer is connected at the other end. I am learning as I go, I'm afraid. I had a quick look earlier today. Presumably, some are mains feed in, some to boiler and some to junction box, connected to actuator/stats?? Haven't yet had the chance to really work my head around it.

Ha, ha. The Blue wire is showing as live mind. Should this be connected to something??

 

[OnOff]

The "click" you hear to indicate the room stat is "calling" for heat could simply be the mechanical action of the bi-metallic strip - it'll do that straight out of the box without being connected up even!

If you look at a programmer diagram you should see the wire from the CH on of the programmer goes to the room stat. From there it goes to the 3-port. With a meter set to >230VAC you should be able to see if the valve is "getting" the call from the room stat. BUT don't try this if you're not au fait.

To test you could temporarily bridge out the room stat whilst the programmer is calling for heat and that would prove whether the stat is as fault but again only if you know what you're doing.

This on the assumption that it is all wired correctly in the first place. Silly question, did it all work properly before?

 

[duffbeerdaddy]

Thanks. That's all really good advice and I'll give it a try. I am quite competent with these things, once directed by kind folk such as yourself. It's in my nature, if you know what I mean.

Not a silly question at all and the answer is I don't know. All I know is that when I came to give the pump a run (as, after my father passed away, the system had been idle) I got nothing on the C/H side. My Father was a bit of a jack of all trades and I could see a bit of DIY soldering on the board controlling the synchronous motor on the actuator/valve. This is what caused me to question its functionality and, since, question the wiring. I don't know if he tried to bridge anything for some reason??

Anyway, I'll give it a go on your suggestion and see how I get on.

Cheers for now.

 

[OnOff]

Thanks. That's all really good advice and I'll give it a try. I am quite competent with these things, once directed by kind folk such as yourself. It's in my nature, if you know what I mean.

Not a silly question at all and the answer is I don't know. All I know is that when I came to give the pump a run (as, after my father passed away, the system had been idle) I got nothing on the C/H side. My Father was a bit of a jack of all trades and I could see a bit of DIY soldering on the board controlling the synchronous motor on the actuator/valve. This is what caused me to question its functionality and, since, question the wiring. I don't know if he tried to bridge anything for some reason??

Anyway, I'll give it a go on your suggestion and see how I get on.

Cheers for now.

Not unknown to repair the pcb on the 3-ports. Done my own a few times with micro switches etc from RS/Maplin etc. If I were you I'd start with a wiring diagram and go from there. As in when the programmer calls for CH/HW do you get 230V at the outputs. Ditto at the output from the stats - and is that reaching the 3-port. I do wonder though at what's going on at your wiring centre!

Think I've got some Grasslin/Tower ones somewhere that should be enough to give you an idea, which I'll scan. Thing is you want this sorted before the frosts set in!

 

[OnOff]

Must admit I reckon my oil boiler is on it's last legs so hoping it lasts the winter! This scanned from all my collected bumpf, vintage 1998 ish: 

 

[duffbeerdaddy]

Thanks Onoff. That'll defo come in handy. Yes, the frost is a worry, though I have found that I can get the heating on as long as water is on. Didn't think to mention that before. Does that spark any ideas as to the problem??

 

[OnOff]

if you hadn't already replaced the valve I'd have said that but as you have then first check everything is wired correctly.

 

[duffbeerdaddy]

Just been to the house quickly on my way to work. Wired direct to 'call for heat' from programmer - same repeated clicking noise coming from actuator. Opened the housing and could see the spring /arm just twitching back and fore. Clicking seemed to be comming from microswitches, so just touched on one with a little electician's screwdriver. The arm moved across and the heating came on!!

Does this indicate a bad connection inside the actuator with the microswitch or is it getting mixed signals (ie on/off/on/off) from programmer??

I would swap out the programmer to rule that out but I see their about £90 new.

 

[SPECIAL LOCATION]

I'm trying to avoid having to call anyone out, as I am trying to act in the best interest of the estate and save some costs for all beneficiaries by doing it myself. False economy perhaps, as it's already set me back £80.

Could it be the programmer at fault??

Any help or advice would be very gratefully received!

Hmmm....

Classic failure to do logical fault diagnosis I am affraid....

You have got too many unproven assumptions going on I think?

and made the whole process more expensive IMHO..

I have said this before but I will say it again...

Keep a few golden rules in you mind at all times:-  

1/ NEVER ASSUME ANY COMPONENT IS GOOD OR FAULTY UNLESS YOU HAVE PROVED IT YOURSELF FIRST!!

2/ There is no standard wiring colour scheme of configuration for any heating system. 

3/ Whilst there are numerous guidelines for interconnecting various heating components..

such as the drawings that come with certain items.. 

The system can be wired with all sorts of colored cables dependent upon what the plumber/heating engineer etc.. had available when the system was installed!!

So with that in mind how it should be approached IMHO....

Heating control systems are just a group of series and parallel wired switches to get a live voltage to fire a boiler at predetermined times or temperatures... 

e.g.

Supply -> Program timer -> Thermostat {room or cylinder} -> Valve actuator switch -> Boiler

May also be :-

Supply Frost stat -> Pipe stat -> Boiler

The three-port valve setup has a slight non standard arrangement to get the valve to position correctly

[WATER ONLY ON]

Supply -> Program timer -> Cylinder stat on -> Boiler    {this signal does NOT need to position the valve}

[HEATING AND WATER ON]

Supply -> Program timer -> Cylinder stat on -> Boiler  {this signal does NOT need to position the valve}

also

Supply -> Program timer -> Room stat on -> Valve motor (white) to mid position {this signal only needs to position the valve, it does not need to fire the boiler, as the boiler is fired via the water signal}

[HEATING ON AND WATER OFF]

Supply -> Program timer -> Cylinder stat off-> Valve motor (grey) to full position {this signal is needed to move the valve to the HEATING ONLY furthest position.}

also

Supply -> Program timer -> Room stat on -> Valve motor (white) -> Valve switch out on Orange-> Boiler {this signal outputs 230v when the valve is in furthest position when both white and grey are at 230v}

Any competent electrician (or DIY'er) can easily test the operation of any heating valve with a few suitable connectors (e.g. wagos), a 3a plug and some flex and a proper test meter that can read mains voltages.

I would have assumed the whole system had not worked properly for years and gone back to basics....

isolated individual components out of the system tested their electrical and mechanical operation...

Then once individual items had been proved and tested wire them back into the system..

while also verifying the wiring arrangment...

From what I have read so far...

I don't think you have actually proved much yet???

All of the above is of course also assuming there are no airlocks or pipe blockages (sludge etc.) in the pipe system...?

Heating that has not been run much over the summer often has sludge or air bleeding issues that need resolving when restarted after long idle periods. 

are there any pipe stats turning your heating back off cuz the water is not flowing correctly and pipes are getting too hot? 

Is the pump working correctly?  is it a fully pumped system?

or has part of it been running off gravity fed water ?

too many unknowns at this stage

:C

 

[OnOff]

You could start with a photo of the wiring centre and maybe post up the details on the programmer so we can find a diagram. The thing about colours varying is so true. Think mine is done with 7-core trailer cable by the looks of it!

 

[duffbeerdaddy]

Thanks special location. Very detailed and useful (once I get my head around all that)

.

I have uploaded a photo and labelled to show what I think is going on. I know I am making a lot of guesses (some educated, most not!) as to what is what here. But there are few things that just don't look right (ie the Live from the cable marked L/N/E, which carries no current at any point??? and the blue (H/W on?) that just terminates with nothing connecting to it).

I have tried to test by bi-passing the room stat by wiring the common to switch live and have done the same, connecting the 'C/H on' to common live in back of programmer. Every time I just get clicking from the actuator, which will actually then switch all the way across when I push on the microswitch inside.

I think it is quite possibly time to throw in the towel, but I'm annoyed that it has seemingly beaten me! Arrggh...

junction box wiring photo..pdf

Just to add. I know that when I get both heat and water on together, the radiators are all banging out the heat. Have bed system and am confident there is no air lock or blockage. When I turn call for water off, the heating will then stay on - just won't come on on it's own!!!??

 

[duffbeerdaddy]

Programmer is a Honeywell ST699B. Wiring is as follows, as per Honeywell's own wiring guide:  (Link L-5-8) 7 = H/W off, 6 = H/W on, 3 = C/H on, 2 = N and 1= L.

I have checked this at the house and all is as it should be. Have not yet had opportunity to check if all go to correct terminals at junction box, but this is next on my agenda.